Basal Endogenous Glucose Production Research Articles

Effect of Dapagliflozin on Renal and Hepatic Glucose Kinetics in T2D and NGT Subjects.

Acute and chronic SGLT-2 inhibition increase endogenous glucose production (EGP). However, the organ - liver versus kidney - responsible for the increase in EGP has not been identified. 20 T2DM and 12 NGT subjects received [3-3H]-glucose infusion (to measure total EGP) in combination with arterial and renal vein catheterization and PAH infusion for determination of renal blood flow. Total EGP, net renal arteriovenous balance, and renal glucose production were measured before and 4 hours after dapagliflozin and placebo administration. Following DAPA, EGP increased in both T2D and NGT from baseline to 240 minutes, while there was a significant time-related decrease after placebo in T2D. Renal glucose production at baseline was <5% of basal EGP in both groups and did not change significantly following DAPA in either NGT and T2D. Renal glucose uptake (sum of tissue glucose uptake plus glucosuria) increased in both T2D and NGT following DAPA (P<0.05 vs placebo). The increase in RGU was entirely explained by the increase in glucosuria. Single dose of dapagliflozin significantly increased EGP, which primarily is explained by an increase in hepatic glucose production, establishing the existence of a novel renal-hepatic axis.

151-LB: Postprandial Glucose Metabolism Differs between Early Adolescents and Adults with Type 1 Diabetes

Postprandial glucose turnover in adolescents with type 1 diabetes (T1D) has not been investigated. To do so, we studied adolescents (n=15, age 11.5±0.5 yrs, BMI 19±2.3 kg/m2, HbA1c 7.5±1%, diabetes duration 4.6±3 yrs) and adults (n=15, age 36.3±9.4 yrs, BMI 27.1±2.1 kg/m2, HbA1c 6.9±1.1%, diabetes duration 18.1±9.6 yrs) with T1D after a mixed meal. Healthy adults (n=14, age 26.9 ± 7 yrs, BMI 24.9±2.5 kg/m2, HbA1c 5.0±0.3%) served as controls. T1D subjects administered their customary insulin bolus dose at meal onset. Rates of endogenous glucose production (EGP) , meal glucose appearance (MRa) and glucose disappearance (Rd) were calculated by the triple tracer method with stable isotopes ([1-13C] glucose, [2-13C] glucose and [6, 6-2H2] glucose) . Integrated glucose excursions did not differ between adolescents and adults with T1D during early (0-120 min) and total (0-300 min) postprandial periods. While basal EGP at start of the meal was higher (p&amp;lt;0.01) , integrated rates of EGP, MRa, Rd and glucose clearance were all lower (p&amp;lt;0.03) in adolescents than in adults with T1D during the early postprandial period and were numerically lower (p=0.08) during the total postprandial period (Figure1) . Taken together, the data demonstrates significant differences in postprandial glucose metabolism between adolescents and adults with T1D. Additional studies are ongoing to determine the causes of these differences. Disclosure F. Ruchi: None. D. Romeres: None. S. Gururaj: None. M. D. Deboer: Research Support; Dexcom, Inc., Tandem Diabetes Care, Inc. R. Basu: Consultant; Sparrow Pharmaceuticals Inc, Research Support; Abbott Diabetes, AstraZeneca. A. Basu: Speaker's Bureau; Zealand Pharma A/S. Funding DK 124886, DK 085516, DK 029953

Adaptation of Insulin Clearance to Metabolic Demand Is a Key Determinant of Glucose Tolerance.

With the development of insulin resistance (IR), there is a compensatory increase in the plasma insulin response to offset the defect in insulin action to maintain normal glucose tolerance. The insulin response is the result of two factors: insulin secretion and metabolic clearance rate of insulin (MCRI). Subjects (104 with normal glucose tolerance [NGT], 57 with impaired glucose tolerance [IGT], and 207 with type 2 diabetes mellitus [T2DM]), divided in nonobese and obese groups, received a euglycemic insulin-clamp (40 mU/m2 ⋅ min) and an oral glucose tolerance test (OGTT) (75 g) on separate days. MCRI was calculated during the insulin-clamp performed with [3-3H]glucose and the OGTT and related to IR: peripheral (glucose uptake during the insulin clamp), hepatic (basal endogenous glucose production × fasting plasma insulin [FPI]), and adipocyte (fasting free fatty acid × FPI). MCRI during the insulin clamp was reduced in obese versus nonobese NGT (0.60 ± 0.03 vs. 0.73 ± 0.02 L/min ⋅ m2, P < 0.001), in nonobese IGT (0.62 ± 0.02, P < 0.004), and in nonobese T2DM (0.68 ± 0.02, P < 0.03). The MCRI during the insulin clamp was strongly and inversely correlated with IR (r = -0.52, P < 0.0001). During the OGTT, the MCRI was suppressed within 15-30 min in NGT and IGT subjects and remained suppressed. In contrast, suppression was minimal in T2DM. In conclusion, the development of IR in obese subjects is associated with a decline in MCRI that represents a compensatory response to maintain normal glucose tolerance but is impaired in individuals with T2DM.

Salicylate administration suppresses the inflammatory response to nutrients and improves ovarian function in polycystic ovary syndrome.

Oxidative stress (OS) and inflammation are often present in polycystic ovary syndrome (PCOS). We examined the effects of salsalate treatment on nutrient-induced OS and inflammation, ovarian androgen secretion, ovulation, and insulin sensitivity in PCOS. Eight lean insulin-sensitive women with PCOS and eight age- and body composition-matched ovulatory controls for baseline comparison participated in the study. The women with PCOS underwent a 12-wk treatment of salsalate, a nonsteroidal anti-inflammatory drug, at a dose of 3 g daily. Markers of OS and inflammation were quantified in mononuclear cells (MNC) and plasma from blood drawn fasting and 2 h after saturated fat ingestion before and after treatment. Ovarian androgen secretion was assessed from blood drawn fasting and 24, 48, and 72 h after human chorionic gonadotropin (HCG) administration before and after treatment. Ovulation was documented based on biphasic basal body temperatures and luteal range progesterone elevations. A two-step pancreatic clamp was performed pre- and posttreatment to measure basal endogenous glucose production (EGP) and the steady-state glucose disposal rate (GDR) during the euglycemic phase and markers of OS and inflammation in MNC and plasma during the hyperglycemic phase. Salsalate administration suppressed lipid- and glucose-stimulated reactive oxygen species generation, activated nuclear factor-κB and circulating tumor necrosis factor-α, normalized basal androgen levels, and lowered HCG-stimulated androgen secretion without altering EGP or GDR. Four salsalate-treated subjects responded with two consecutive ovulations. We conclude that in PCOS, salsalate-induced suppression of OS and inflammation ameliorates ovarian androgen hypersecretion and may induce ovulation while maintaining insulin action.

Clinical Parameters, Fuel Oxidation, and Glucose Kinetics in Patients With Type 2 Diabetes Treated With Dapagliflozin Plus Saxagliptin.

To examine the mechanisms responsible for improved glycemia with combined sodium-glucose cotransporter 2 inhibitor (SGLT2i) plus dipeptidyl peptidase 4 inhibitor therapy in type 2 diabetes. Fifty-six patients (HbA1c 8.9 ± 0.2% [74 ± 2 mmol/mol]) were randomized to dapagliflozin (DAPA) 10 mg, DAPA/saxagliptin (SAXA) 10/5 mg, or placebo (PCB) for 16 weeks. Basal endogenous glucose production (EGP) (3-3H-glucose), urinary glucose excretion, glucose/lipid oxidation, HbA1c, and substrate/hormone levels were determined before treatment (Pre-Tx) and after treatment (Post-Tx). At week 16, HbA1c decrease was greater (P < 0.05) in DAPA/SAXA (-2.0 ± 0.3%) vs. DAPA (-1.4 ± 0.2%) and greater than PCB (0.2 ± 0.2%). Day 1 of drug administration, EGP (∼2.40 mg/kg/min) decreased by -0.44 ± 0.09 mg/kg/min in PCB (P < 0.05) but only by -0.21 ± 0.02 mg/kg/min in DAPA and DAPA/SAXA (P < 0.05 vs. PCB). At week 16, EGP increased to 2.67 ± 0.09 mg/kg/min (DAPA) and 2.61 ± 0.08 mg/kg/min (DAPA/SAXA), despite reductions in fasting plasma glucose by 47 and 77 mg/dL, respectively, and no changes in PCB. Baseline plasma free fatty acids rose by 40 µmol/L with DAPA but declined by -110 with PCB and -90 µmol/L with DAPA/SAXA (P < 0.05, Pre-Tx vs. Post-Tx). In DAPA, carbohydrate oxidation rates decreased from 1.1 ± 0.1 to 0.7 ± 0.1 mg/kg/min, whereas lipid oxidation rates increased from 0.6 ± 0.1 to 0.8 ± 0.1 mg/kg/min (P < 0.01). In DAPA/SAXA, the shift in carbohydrate (1.1 ± 0.1 to 0.9 ± 0.1 mg/kg/min) and lipid (0.6 ± 0.1 to 0.7 ± 0.1 mg/kg/min) oxidation was attenuated (P < 0.05). The addition of SAXA to DAPA resulted in superior glycemic control compared with DAPA monotherapy partly because of increased glucose utilization and oxidation. Although the decrease in insulin/glucagon ratio was prevented by SAXA, EGP paradoxical elevation persisted, indicating that other factors mediate EGP changes in response to SGLT2i-induced glucosuria.

1832-P: Palmitic Acid Esters of Hydroxy Stearic Acids Reduce Endogenous Glucose Production through GPR43 Activation

Palmitic Acid esters of Hydroxy Stearic Acids (PAHSAs), bioactive lipids with anti-inflammatory and antidiabetic effects, improve systemic and hepatic insulin sensitivity in insulin-resistant mice. PAHSAs augment insulin action on endogenous glucose production (EGP) through direct and indirect actions involving inter-tissue communication between liver and adipose tissue. The direct effect of PAHSAs to inhibit EGP is mediated through a cAMP dependent pathway involving Gα/i protein-coupled receptors. Here, we investigated which receptor mediates PAHSA effects on EGP. We found that 9-PAHSA activates GPR43 in a Ca+2 flux assay. 4-CMTB (0.4μM), a selective agonist-allosteric modulator of GPR43, reduced basal EGP by 23% and glucagon-stimulated EGP by 20% in primary hepatocytes ex vivo. Acute 9-PAHSA treatment (40μM) inhibited basal EGP to the same extent as 4-CMTB. 9-PAHSA suppression of basal EGP was abolished in primary hepatocytes from whole body GPR43 KO mice. Intravenous infusion of 9-PAHSA (9μg/hr) for 3 hrs decreased ambient EGP in chow-fed mice studied 5 hours after food removal (WT: vehicle= 24.2±1.9 vs. PAHSA= 17.2±0.7 mg/kg/min p&amp;lt;0.05). This effect was absent in GPR43 KO mice (KO: vehicle= 25.3±4.2 vs. PAHSA= 23.4±2.7 mg/kg/min). We also examined whether GPR43 activation is required for the direct effect of 9-PAHSA on WAT lipolysis. Treatment with the β-adrenergic agonist isoproterenol increased FFA release from WAT explants by 3.8-fold, and 9-PAHSA inhibited isoproterenol-induced lipolysis by 21% which was similar to the effects of insulin and 4-CMTB. In WAT explants from GPR43 KO mice, 9-PAHSA suppression of isoproterenol-induced FFA release was abolished while insulin still suppressed lipolysis. Sum: 9-PAHSA activates GPR43, which is involved in its direct effects to reduce hepatic glucose production and WAT lipolysis. Conclusion: We have identified a new receptor that mediates some of the beneficial metabolic effects of PAHSAs. Disclosure A. Santoro: None. P. Zhou: None. Y. Zhu: None. O.D. Peroni: None. A.T. Nelson: None. D. Siegel: None. B. Kahn: Advisory Panel; Self; Harrington Discovery Institute, Janssen Pharmaceuticals, Inc., National Institute of Diabetes and Digestive and Kidney Diseases. Funding American Diabetes Association (1-18-PDF-134 to P.Z.); National Institutes of Health (DK43051, DK57521, DK106210, DK112622); JPB Foundation; American Heart Association

1135-P: Acute Increase in Endogenous Glucose Production by a Single Administration of Tofogliflozin Is Disappeared by Suppressing Its Glucose Lowering Effect in the Patients with Type 2 Diabetes Mellitus

It has been shown that a single administration of SGLT2 inhibitor (SGLT2i) to the patients with type 2 diabetes mellitus (T2DM) decreases plasma glucose (PG), but increases endogenous glucose production (EGP); however, its underlying mechanism has been totally unknown. We hypothesized that a single administration of SGLT2i lowers PG, thereby suppresses insulin level and increases glucagon level, which in turn rises EGP. To test this hypothesis, we recruited 12 Japanese patients with type 2 diabetes mellitus without taking any hypoglycemic agents (BMI 24.9±2.5 kg/m2, HbA1c 7.7±0.9%). In each patient, by [6,6-2H2]-glucose infusion, we evaluated basal EGP and EGP under the conditions with: (i) no administration of drugs (CON), (ii) single administration of a SGLT2i, Tofogliflozin (TOF), and (iii) TOF + glucose adjustment (TOF+G) in which we adjusted PG level by exogenous glucose infusion to mimic PG level during CON. In each patient, we measured EGP under three condition at 1-2 week intervals. Also, we evaluated changes in insulin, glucagon and EGP between basal period and after each 3h condition. The decrement of PG during 3h experimental period in TOF was significantly greater than that in CON, and this change was inhibited by glucose infusion (delta PG: CON; -14.6 mg/dl, TOF; -26.4 mg/dl, TOF+G; -15.6 mg/dl). In CON, EGP was decreased by 11.1%, but it was significantly increased by 4.5% in TOF. However, similar to CON, EGP was decreased by 15.7% in TOF+G. In addition, insulin level was decreased by 24% and glucagon level was increased by 36% in TOF; however, these hormonal changes were not observed in CON and TOF+G. In conclusion, acute EGP elevation by a single administration of SGLT2i was disappeared by suppression of glucose lowering effect of SGLT2i. Changes in insulin and glucagon by rapid decline of PG after SGLT2i administration may be a main inducer of EGP elevation. Disclosure N. Yamasaki: None. Y. Tamura: Advisory Panel; Self; Astellas Pharma Inc. Research Support; Self; Kowa Company, Ltd. Speaker’s Bureau; Self; Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd. H. Kaga: None. M. Sato: None. M. Kiya: None. S. Kadowaki: None. R. Suzuki: None. Y. Furukawa: None. D. Sugimoto: None. T. Funayama: None. Y. Someya: None. R. Kawamori: None. H. Watada: Advisory Panel; Self; Abbott, Ajinomoto, Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Fuji Film, Janssen Pharmaceuticals, Inc., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi-Aventis, Takeda Pharmaceutical Company Limited, Terumo Medical Corporation. Research Support; Self; Astellas Pharma Inc., Bayer Yakuhin, Ltd., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Kissei Pharmaceutical Co., Ltd., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharma K.K., Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Pfizer Japan Inc., Sanofi-Aventis, Sanwa Kagaku Kenkyusho, Shionogi &amp; Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited, Teijin Pharma Limited, Yakult. Speaker’s Bureau; Self; Astellas Pharma Inc., AstraZeneca, Bayer Yakuhin, Ltd., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Kissei Pharmaceutical Co., Ltd., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi-Aventis, Sanwa Kagaku Kenkyusho, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited. Funding Kowa Company, Ltd.

PAHSAs enhance hepatic and systemic insulin sensitivity through direct and indirect mechanisms.

Palmitic acid esters of hydroxy stearic acids (PAHSAs) are bioactive lipids with antiinflammatory and antidiabetic effects. PAHSAs reduce ambient glycemia and improve glucose tolerance and insulin sensitivity in insulin-resistant aged chow- and high-fat diet-fed (HFD-fed) mice. Here, we aimed to determine the mechanisms by which PAHSAs improve insulin sensitivity. Both acute and chronic PAHSA treatment enhanced the action of insulin to suppress endogenous glucose production (EGP) in chow- and HFD-fed mice. Moreover, chronic PAHSA treatment augmented insulin-stimulated glucose uptake in glycolytic muscle and heart in HFD-fed mice. The mechanisms by which PAHSAs enhanced hepatic insulin sensitivity included direct and indirect actions involving intertissue communication between adipose tissue and liver. PAHSAs inhibited lipolysis directly in WAT explants and enhanced the action of insulin to suppress lipolysis during the clamp in vivo. Preventing the reduction of free fatty acids during the clamp with Intralipid infusion reduced PAHSAs' effects on EGP in HFD-fed mice but not in chow-fed mice. Direct hepatic actions of PAHSAs may also be important, as PAHSAs inhibited basal and glucagon-stimulated EGP directly in isolated hepatocytes through a cAMP-dependent pathway involving Gαi protein-coupled receptors. Thus, this study advances our understanding of PAHSA biology and the physiologic mechanisms by which PAHSAs exert beneficial metabolic effects.

245-OR: Glucose Production and Utilization following Oral Glucose Load in Type 2 Diabetes Patients Treated with Dapagliflozin Alone and in Saxagliptin Combination

Objectives and Methods: To examine changes in endogenous glucose production (EGP). Tissue glucose disappearance (Rd) and urinary glucose excretion (UGE) after SGLT2i alone and combined with DPP-4i. We randomized (2:2:1) 56 T2D patients (A1c=8.9±0.2, FPG=178±10, BMI=34±1.3) to receive dapagliflozin 10 mg [n=22, D], dapagliflozin/saxagliptin 10/5 mg [n=22, D/S], placebo [n=12, P]. Subjects received 75 g OGTT (240 min) with [3H-glu] IV and [14C-glu ] orally pre and post treatment (Tx) for 4 months. Results: Post-Tx, A1c increased by 0.1±0.4% in P and decreased (p&amp;lt;001) by 1.4±0.2% in (D) and 1.9±0.3% in (D/S) (p&amp;lt;0.001). FPG decreased by 44 (D) and 56 (D/S) mg/dl (p &amp;lt;0.001) and was unchanged with (P). During OGTT, increment in PG was reduced by 21 (D) and 29 (D/S) (p&amp;lt;0.001) and increased by 12 mg/dl in (P).Pre-Tx, basal EGP was similar in 3 groups (~2.4 mg/kg.min) and decreased by ~50% during OGTT. Post-Tx, despite the marked decrease in FPG, basal EGP increased in both D and D/S; EGP suppression ~50% during OGTT was unchanged in D and D/S. Pre-Tx, UGE (mg/kg.min) during OGTT was negligible in 3 groups: Post-Tx, UGE increased to 1.0±0.1 (D) and 1.1±0.1 (D/S) (p&amp;lt;0.01) but not in P. Pre-Tx, Tissue Rd (mg/kg.min) increased similarly during OGTT in all 3 groups by ~ 40%; Post-Tx, the increase in Tissue Rd was greater (p&amp;lt;0.05) in D (∆1.7±0.3) and D/P (∆3.8±0.3) vs. P (∆1.4±0.2). Pre-Tx, basal glucose clearance (GC) was similar in all 3 groups (~1.4 ml/kg.min) and did not change during OGTT. Post-Tx, both basal GC and GC during OGTT increased (p&amp;lt;0.05-0.01) in D and D/S, without change in plasma insulin/C-peptide conc. Conclusions: D and D/S treatment improved glycemic control by (i) increasing UGE and (ii) augmenting Tissue glucose clearance by ameliorating glucotoxicity, Saxa addition to dapa produced only modest further A1c reduction because it failed to block dapagliflozin-induced stimulation of EGP, even though it increased insulin and decreased glucagon secretion. Disclosure Y. Qin: None. A. Gastaldelli: Consultant; Self; A. Menarini Diagnostics, Eli Lilly and Company, Genentech, Inc., Gilead Sciences, Inc., Inventiva Pharma. M. Abdul-Ghani: None. J.M. Adams: None. A.M. Ali: None. M.M. Eletrebi: None. R.A. Martinez: None. C.L. Triplitt: Consultant; Self; Abbott. Speaker's Bureau; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Janssen Pharmaceuticals, Inc. R.A. DeFronzo: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Elcelyx Therapeutics, Inc., Intarcia Therapeutics, Inc., Janssen Pharmaceuticals, Inc., Novo Nordisk Inc. Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Merck &amp; Co., Inc. Speaker&amp;s Bureau; Self; AstraZeneca, Novo Nordisk Inc. E. Cersosimo: None. Funding AstraZeneca

1846-P: The Insulin-Sensitizing Effects of Palmitic Acid Esters of Hydroxy Stearic Acids Involve Intertissue Communication

Palmitic Acid esters of Hydroxy Stearic Acids (PAHSAs), bioactive lipids with anti-inflammatory and antidiabetic effects, improve glucose tolerance and insulin sensitivity in insulin-resistant mice. We found that PAHSA treatment enhances insulin action to suppress endogenous glucose production (EGP) in chow and HFD mice and promotes glucose uptake in glycolytic muscle and heart in HFD-fed mice. We aimed to determine the mechanisms by which PAHSAs enhance hepatic insulin sensitivity. We examined both direct effects in hepatocytes and indirect effects resulting from augmentation of insulin-mediated suppression of WAT lipolysis. Here, we show that PAHSAs inhibit lipolysis in WAT explants to the same extent as insulin. PAHSAs also enhance the anti-lipolytic effect of insulin in vivo, as indicated by a 30% reduction in FFAs during the clamp in PAHSA-treated mice under conditions with no suppression in Vehicle treated mice. To determine whether lowering FFAs is necessary for PAHSA effects on insulin sensitivity, we infused intralipid during a hyperinsulinemic-euglycemic clamp. In chow-fed mice infused with intralipid, PAHSAs still have a partial effect to lower EGP (Intralipid: vehicle 12±0.8 vs. PAHSA 7±1.7 mg/kg/minute), whereas in HFD-fed mice, preventing PAHSA-induced FFA reduction blocks PAHSA effects on hepatic insulin sensitivity (EGP Intralipid: vehicle 13±0.6 vs. PAHSA 12±1.7 mg/kg/minute). Our mechanistic studies show that PAHSAs inhibit basal EGP and reduce glucagon stimulated EGP directly in isolated hepatocytes. This is mediated by a cAMP-dependent pathway involving Gα/i protein-coupled receptors. Hepatic phospho-CREB is also reduced by PAHSAs in vivo. Sum: PAHSAs enhance hepatic insulin sensitivity through direct and indirect actions involving inter-tissue communication between adipose tissue and liver. These data reveal new mechanisms underlying the beneficial effects of PAHSAs, which will clarify their roles in healthy and disease states. Disclosure P. Zhou: None. A. Santoro: None. O.D. Peroni: None. A.T. Nelson: None. A. Saghatelian: None. D. Siegel: None. B. Kahn: Advisory Panel; Self; Alterna Therapeutics, Inc., American Diabetes Association, Harrington Discovery Institute, Janssen Research &amp; Development. Consultant; Self; Ironwood Pharmaceuticals, Inc. Research Support; Self; National Institute of Diabetes and Digestive and Kidney Diseases. Funding American Diabetes Association (1-18-PDF-134 to P.Z.); National Institutes of Health (R01DK43051 to B.K.), (R01DK106210 to B.K., A.S.); JPB Foundation (to B.K.); American Heart Association (to A.T.N.)

OR07-3 Validation of Surrogate Models to Assess Tissue and Whole-Body Insulin Resistance Among High-Risk Adolescent Girls

Polycystic Ovarian Syndrome (PCOS) is a common endocrine disorder which develops in adolescence and affects 6-10% of women. PCOS is associated with insulin resistance (IR), which can occur in multiple tissues, in particular skeletal muscle and liver. Reliable assessment of tissue-specific IR in youth with PCOS is important for development of new therapies. The gold-standard method to assess tissue-IR is the hyper-insulinemic euglycemic clamp, a method which is too intensive for use in routine research. We aimed to validate surrogate indices (the oral minimal model (OMM)-derived whole-body index and the Abdul-Ghani model-derived muscle index and liver index) against their respective clamp measurements in a population of high-IR-risk adolescent girls. 45 adolescent girls (14.6 ± 1.7 years; BMI %ile 23.3%-98.2%) underwent a standard 2-hour oral glucose tolerance test (OGTT) (75g glucose) and a multi-phase hyper-insulinemic euglycemic clamp (10,16 and 80 mU/m2/min) with a glucose isotope tracer. This study was a secondary analysis. OMM total Si was computed using SAAM II software, using 0, 15, 30, 60, 90, 120 min time points and the assumption that glucose rate of appearance (Ra) decays exponentially after 120 min. Abdul-Ghani muscle and liver insulin resistance indices (IRIs) were calculated: liver IRI= AUC0-30min Glucose (mmol L-1 min) x AUC0-30min Insulin (pmol L-1 min); muscle IRI= mean insulin0-120min. Correlation analyses were performed using Spearman’s or Pearson’s correlation, as appropriate. OMM total Si correlated with clamp-measured insulin sensitivity (glucose infusion rate, r=0.65; p<0.0001), whereas muscle IRI did not (p=0.45). Liver IRI correlated moderately with clamp-derived hepatic insulin sensitivity (insulin concentration required to suppress 50% of basal endogenous glucose production; r=0.35; p=0.03). In adolescent girls at high risk of IR, OMM provided a strong surrogate characterization of whole-body IR when evaluated against the clamp. The Abdul-Ghani model indices are simpler to calculate compared to OMM; however, these results suggest that the Abdul-Ghani indices may not be adequate for describing and distinguishing among individuals within a narrower IR range, such as that found in our study population. By contrast, OMM offers an effective, OGTT-based methodology to be used in research studies for characterizing whole-body IR that is less resource-intensive compared to the clamp. Future work is needed to determine if the sensitivity of this model can be further improved with a longer-duration OGTT as obese youth can have an exaggerated and prolonged response to an OGTT. Funding: Thrasher Research Foundation, AHA CRP, Endocrine Society Fellowship in Women's Health, NIDDK K23

Metformin increases endogenous glucose production in non-diabetic individuals and individuals with recent-onset type 2 diabetes.

Metformin is the endorsed first-line glucose-lowering drug for treating patients with type 2 diabetes but despite more than 50years of use, no consensus has been reached on its mechanisms of action. In this study, we investigated the glucose-lowering effects of metformin in individuals with type 2 diabetes and non-diabetic individuals. We performed a randomised, placebo-controlled trial in 24 individuals with recent-onset type 2 diabetes (diabetes duration 50 [48] months) who had good glycaemic control (HbA1c 48mmol/mmol [6.5%]). The studies were conducted at Aarhus University Hospital between 2013 and 2016. Participants were randomised to receive either metformin (2000mg/day, n = 12, MET group) or placebo (n = 12, PLA group) for 90days, using block randomisation set up by an unblinded pharmacist. Two participants withdrew from the study prior to completion and were replaced with two new participants receiving the same treatment. In addition, we recruited a group of non-diabetic individuals with similar age and BMI (n = 12, CONT group), who were all treated with 2000mg metformin daily. Before and after treatment all individuals underwent studies of whole-body glucose metabolism by non-steady-state [3-3H]glucose kinetics, hyperinsulinaemic-euglycaemic clamping, indirect calorimetry, metabolomics, dual x-ray absorptiometry and muscle biopsies. The primary study endpoint was the effect of metformin treatment on lipid kinetics as well as glucose rate of disappearance (Rd) and endogenous glucose production (EGP). One participant from the CONT group withdrew due to intolerable gastrointestinal side-effects and was excluded from analysis. As expected, metformin treatment lowered fasting plasma glucose (FPG) in the MET group (~1.5mmol/l, p < 0.01), whereas no effect was observed in the PLA and CONT groups. Body weight and composition did not change in any of the groups. In both of the metformin-treated groups (MET and CONT), basal glucose Rd, EGP and glucagon levels increased by ~30% (p < 0.05) whereas this was not the case in the PLA group. Ninety days of metformin treatment resulted in similar increases in EGP and glucose Rd in individuals with recent-onset type 2 diabetes and in non-diabetic control individuals. These results challenge the existing paradigm that metformin primarily acts in the liver by inhibiting EGP, at least in individuals with type 2 diabetes of short duration and who have discretely affected glycaemic status. Whether metformin increases basal glucose Rd by facilitating glucose uptake in other tissues such as the intestines remains to be further clarified. ClinicalTrials.gov NCT01729156 FUNDING: This study was supported by grants from The Danish Council for Independent Research | Medical Sciences, Aase Danielsen Fund, the Novo Nordisk Foundation, the Danish Diabetes Association and the Danish Diabetes Academy supported by the Novo Nordisk Foundation.

Effect of Chronic Hyperglycemia on Glucose Metabolism in Subjects With Normal Glucose Tolerance.

Chronic hyperglycemia causes insulin resistance, but the inheritability of glucotoxicity and the underlying mechanisms are unclear. We examined the effect of 3 days of hyperglycemia on glucose disposal, enzyme activities, insulin signaling, and protein O-GlcNAcylation in skeletal muscle of individuals without (FH−) or with (FH+) family history of type 2 diabetes. Twenty-five subjects with normal glucose tolerance received a [3-3H]glucose euglycemic insulin clamp, indirect calorimetry, and vastus-lateralis biopsies before and after 3 days of saline (n = 5) or glucose (n = 10 FH− and 10 FH+) infusion to raise plasma glucose by ∼45 mg/dL. At baseline, FH+ had lower insulin-stimulated glucose oxidation and total glucose disposal (TGD) but similar nonoxidative glucose disposal and basal endogenous glucose production (bEGP) compared with FH−. After 3 days of glucose infusion, bEGP and glucose oxidation were markedly increased, whereas nonoxidative glucose disposal and TGD were lower versus baseline, with no differences between FH− and FH+ subjects. Hyperglycemia doubled skeletal muscle glycogen content and impaired activation of glycogen synthase (GS), pyruvate dehydrogenase, and Akt, but protein O-GlcNAcylation was unchanged. Insulin resistance develops to a similar extent in FH− and FH+ subjects after chronic hyperglycemia, without increased protein O-GlcNAcylation. Decreased nonoxidative glucose disposal due to impaired GS activation appears to be the primary deficit in skeletal muscle glucotoxicity.

Glucose lowering and vascular protective effects of cycloset added to GLP-1 receptor agonists in patients with type 2 diabetes.

SummaryObjectiveTo determine the glucose‐lowering mechanism of action and the effects of a quick‐release bromocriptine‐QR, a D2‐dopamine agonist (Cycloset) on vascular function in patients with type 2 diabetes (T2D).Study design and methodsFifteen poorly controlled T2D treated with metformin plus glucagon‐like peptide‐1 receptor agonists (GLP‐1RA) were studied after 4 months of Cycloset, 3.2 mg/d. Subjects received a 5‐hour double‐tracer (iv 3‐3H‐glucose and oral 14C‐glucose) mixed meal test (MMT) to quantitate rates of endogenous glucose production (EGP), oral glucose appearance (RaO) and disappearance (Rd) pre‐ and post‐Cycloset. Vascular assessments included 2‐day continuous BP monitoring, reactive hyperaemia index (RHI) and arterial stiffness (AS).ResultsHbA1c decreased from 8.3 ± 0.3% to 7.7 ± 0.2% (P < 0.05), fasting plasma glucose did not change (143 ± 4 vs 147 ± 5) and mean plasma glucose during MTT decreased from 223 ± 3 to 210 ± 4 mg/dL (P < 0.05) after Cycloset. Basal EGP (2.2 ± 0.2 vs 2.1 ± 0.2 mg/kg min) was unchanged, but there was greater MMT suppression (1.1 ± 0.1 vs 0.7 ± 0.1, P < 0.05). After Cycloset, RaO declined from 2.0 ± 0.1 to 1.7 ± 0.2 mg/kg min and peripheral oral glucose appearance from 53.1 ± 3.2 to 44.4 ± 3.1 g (P < 0.01). There were no changes in plasma insulin or glucagon concentration. Systolic (134 ± 4 vs 126 ± 6), diastolic (78 ± 3 vs 73 ± 4), mean BP (97 ± 5 vs 90 ± 4) and pulse pressure (54 ± 2 vs 51 ± 2 mm Hg) were reduced; RHI increased from 1.4 ± 0.1 to 1.9 ± 0.3 au and AS decreased modestly (19.8 ± 4.1 to 16.2 ± 3.7 au, P = NS).ConclusionsAddition of Cycloset to GLP‐1 RA improved vascular indices and postprandial hyperglycaemia in T2DM primarily by lowering oral glucose appearance, suggesting that hepatic glucose uptake was enhanced. Improved vascular indices may explain the reduction in cardiovascular events observed with Cycloset therapy in patients with T2DM.

Dietary Rapeseed Oil Supplementation Reduces Hepatic Steatosis in Obese Men

Obesity is associated with nonalcoholic fatty liver disease (NAFLD) leading to increased hepatic glucose production. NAFLD is one of the most frequent liver diseases however, effective treatment is limited. Animal studies showed a reduction in hepatic steatosis with dietary alpha linoleic acid, which is highly enriched in rapeseed oil (RA). In this study we used a nutritional therapeutic approach and investigated the effect of an isocaloric diet supplemented with RA or olive oil (OL) on liver fat content, endogenous glucose production, total body insulin sensitivity and serum lipids in obese humans suffering from NAFLD. 27 obese men (BMI 30-35, age 18-65) consumed an isocaloric diet including 50 g of either RA (n=12) or OL (n=15) daily for eight weeks. Hepatic MRI, hyperinsulinemic-euglycemic clamp studies with isotope labelled glucose and blood tests were performed prior to and at the end of the study to assess liver fat content, endogenous glucose production and cholesterol and free fatty acid levels, respectively. Body fat content and BMI did not change over the time of intervention for RA and OL. At the end of the study a significant reduction in hepatic fat content (P=0.038) could be observed for RA (13.09±1.61 before vs. 11.14±1.58% after intervention) vs. OL (13.29±2.52 before vs. 15.73±2.74% after intervention). For RA, a 21% reduction (P&amp;lt;0.02) in serum free fatty acids was observed after eight weeks of oil consumption whereas no significant changes were seen for OL. Consuming RA resulted in a slight reduction in basal endogenous glucose production (1.71±0.15 before vs. 1.49±0.mg/kg/min after intervention, P=n.s.) compared to OL (1.66±0.before vs. 1.65±0.mg/kg/min after intervention, P=n.s.). There were no significant changes in total body insulin sensitivity and serum cholesterol levels in RA or OL. Our results demonstrate a beneficial effect of the fatty acid composition of RA on hepatic lipid production as shown by reduced hepatic fat content and free fatty acid levels. Disclosure M. Kruse: None. M. Kemper: None. S. Gancheva: None. D. Dannenberger: None. D.F. Markgraf: None. M. Roden: Speaker's Bureau; Self; Boehringer Ingelheim GmbH. Research Support; Self; Boehringer Ingelheim GmbH. Consultant; Self; Poxel SA. Research Support; Self; Danone Nutricia Early Life Nutrition, GlaxoSmithKline plc., Nutricia Advanced Medical Nutrition, Sanofi. A.F. Pfeiffer: None.

Glucagon Resistance at the Level of Amino Acid Turnover and Ureagenesis in Obese Subjects with Hepatic Steatosis

Hyperglucagonemia is considered an important pathophysiological trait of type 2 diabetes and occurs also in individuals with obesity. The underlying mechanisms remain unclear. We hypothesized that hyperglucagonemia is a consequence of steatosis-induced glucagon resistance. We examined 15 healthy (BMI: 23.2±1.6 (mean±SD) kg/m2, age 40.9±12.8 years, hepatic steatosis 2:15) and 15 obese individuals (BMI: 33.6±2.1 kg/m2, age 35.8±9.4 years, hepatic steatosis 14:15) in a pancreatic somatostatin clamp with basal insulin (1 mU/kg/h) and low and high glucagon infusion rates (0.6 and 3.0 ng/kg/min). Glucagon sensitivity was assessed as changes in plasma amino acids (AA) and endogenous glucose production (EGP) and urea synthesis (U.S.) measured by tracer techniques. Basal glucagon and AA were significantly higher in obese compared to lean individuals, but no differences in basal EGP or U.S. were observed. In the lean group AA significantly dropped in response to glucagon infusion (p&amp;lt;0,001) whereas no response was observed in the obese group. Accordingly, both glucagon infusion rates resulted in significantly greater EGP and U.S, respectively, in lean vs. obese individuals. In conclusion, our results point to steatosis-induced hepatic glucagon resistance and compensatory glucagon secretion mediated by glucagonotropic amino acids as a likely explanation of obesity-associated hyperglucagonemia. Disclosure M.P. Suppli: None. J.I. Bagger: None. A.B. Lund: Other Relationship; Self; Novo Nordisk A/S. N.J. Wewer Albrechtsen: Speaker's Bureau; Self; Merck Sharp &amp; Dohme Corp.. Other Relationship; Self; Mercodia, Alpco. J.J. Holst: Advisory Panel; Self; Novo Nordisk A/S. Board Member; Self; Zealand Pharma A/S. Speaker's Bureau; Self; Merck Sharp &amp; Dohme Corp., AstraZeneca. Research Support; Self; Danish Diabetes Academy, Novo Nordisk Foundation. Other Relationship; Self; Antag Therapeutics. Other Relationship; Spouse/Partner; Antag Therapeutics. T. Vilsbøll: Advisory Panel; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Consultant; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Speaker's Bureau; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Research Support; Self; Eli Lilly and Company, Novo Nordisk A/S. F.K. Knop: Advisory Panel; Self; AstraZeneca. Consultant; Self; AstraZeneca. Research Support; Self; AstraZeneca. Speaker's Bureau; Self; AstraZeneca. Advisory Panel; Self; Eli Lilly and Company. Speaker's Bureau; Self; Eli Lilly and Company. Advisory Panel; Self; Amgen Inc.. Speaker's Bureau; Self; Merck Sharp &amp; Dohme Corp.. Advisory Panel; Self; Novo Nordisk A/S. Consultant; Self; Novo Nordisk A/S. Speaker's Bureau; Self; Novo Nordisk A/S. Consultant; Self; Amgen Inc.. Advisory Panel; Self; MedImmune, Sanofi. Consultant; Self; Sanofi. Research Support; Self; Sanofi. Speaker's Bureau; Self; Sanofi.

Palmitic Acid Esters of Hydroxy Stearic Acids Are Hepatic Insulin Sensitizers in Chow and High-Fat Diet (HFD)–Fed Mice

Palmitic Acid esters of Hydroxy Stearic Acids (PAHSAs), bioactive lipids with potent anti-inflammatory and antidiabetic effects, reduce ambient glycemia and improve glucose tolerance and insulin sensitivity in insulin resistant HFD-fed mice. We aimed to determine the mechanisms by which PAHSAs improve insulin sensitivity. We treated chow- and HFD-fed mice with 5-PAHSA (0.1 mg/day) and 9-PAHSA (0.4 mg/day) by SQ osmotic minipumps for 13 weeks. Serum 5-PAHSA levels increased 3.5 fold and 9-PAHSA 2.5 fold in chow-fed mice, while 5-PAHSA levels increased 17 fold and 9-PAHSA 6 fold in HFD-fed mice. PAHSAs had no effect on weight gain or fat mass. We performed hyperinsulinemic euglycemic clamps (2.5 mU/Kg/min insulin infusion rate). PAHSA treatment increased systemic insulin sensitivity in both chow- [glucose infusion rate (GIR): vehicle 13±2 vs. PAHSA 27±4 mg/kg/min] and HFD-fed mice (GIR: vehicle 2±0.5 vs. PAHSA 10±3 mg/kg/min). Endogenous glucose production (EGP) was suppressed 28% by insulin in vehicle-treated mice and 55% in PAHSA-treated mice on chow diet. Remarkably, while insulin failed to suppress EGP in vehicle-treated HFD-fed mice, PAHSA treatment led to a 37% reduction in EGP. PAHSAs also decreased glycemia during a pyruvate tolerance test, indicating that suppression of hepatic gluconeogenesis contributes to the EGP improvement. Mechanistic studies showed that PAHSAs inhibit basal and glucagon-stimulated EGP and reduce cAMP in isolated hepatocytes. This effect is blocked by pertussis toxin indicating it is mediated by Gα/i protein-coupled receptors. PAHSAs also reduce G6pase activity and phosphorylation of CREB in liver. Sum: PAHSAs are systemic insulin sensitizers and augment insulin action on EGP in vivo. In vitro, PAHSAs reduce EGP through a cAMP dependent pathway involving Gα/i protein-coupled receptors. Thus, PAHSAs could be effective antidiabetic agents and the pathways they engage could provide novel drug targets for type 2 diabetes. Disclosure A. Santoro: None. P. Zhou: None. O.D. Peroni: None. I. Syed: None. A.T. Nelson: None. D. Siegel: None. A. Saghatelian: None. B. Kahn: Advisory Panel; Self; Janssen Research &amp; Development. Research Support; Self; Janssen Research &amp; Development. Advisory Panel; Self; Alterna Biotech.

Mild Physiologic Hyperglycemia Induces Hepatic Insulin Resistance in Healthy Normal Glucose Tolerant Subjects–Role of Glucagon and Gluconeogenic Substrates

The aim of the present study was to evaluate the effect of a physiologic increase in plasma glucose concentration on endogenous glucose production (EGP) in healthy NGT individuals. 16 NGT subjects [8 with and 8 without family history of T2DM (9M/7F, age = 44± 3 years, BMI = 26 ± 1 kg/m2)] participated in a 3-step hyperinsulinemic (10, 20, 40 mU/m2 min) euglycemic clamp before and after a 48 hour glucose infusion to increase plasma glucose conc by ∼45 mg/dl above baseline (89±4 to 136±4.9 mg/dl). EGP was measured with [3-3H] glucose and gluconeogenic rate was measured following administration of deuterated water. Plasma FFA, glucagon, lactate, glycerol and alanine concentrations also were measured. Following 48 hours of glucose infusion basal EGP increased from 2.05±0.09 to 3.06±0. mg/kg min (p=0.003) and hepatic insulin resistance index (EGP X Fasting Plasma Insulin) increased markedly and similarly (25.1±1.0 vs. 48.3± 3.2, p&amp;lt;0.005). The baseline plasma glucagon concentration tended to be higher following 48 hours of glucose infusion (64±3 vs. 77± 8 pg/ml, p=0.2) while the product of the plasma glucagon and insulin concentrations was markedly increased (540 ± 56 vs. 1336 ± 262, p=0.004). Although the baseline plasma FFA concentration was markedly reduced following 48 hours of glucose infusion (0.482 ±0.to 0.055± 0.01mM), there was no difference in plasma glycerol concentration (13.4±1.2 vs. 13.3 ± 2.2 mg/L p=ns). There were small increases in both the plasma lactate and alanine concentrations. Total body insulin sensitivity declined from 8.75±2.1 to 6.92± 6 mg.kg/min (p&amp;lt;0.05). Conclusion: Chronic (48 hr) physiologic hyperglycemia to levels seen in T2DM increases basal hepatic glucose production and induces hepatic and skeletal muscle insulin resistance in healthy NGT subjects. These results demonstrate, for the first time that glucotoxicity causes resistance to the suppressive effect of insulin on hepatic glucose production. Disclosure D. Tripathy: None. A. Merovci: None. E.R. Maldonado Corchado: None. R. Basu: Research Support; Self; AstraZeneca. R.A. DeFronzo: Speaker-s Bureau; Self; AstraZeneca, Novo Nordisk Inc.. Advisory Panel; Self; AstraZeneca, Novo Nordisk Inc., Janssen Pharmaceuticals, Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Elcelyx Therapeutics, Inc., Intarcia Therapeutics, Inc.. Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Takeda Pharmaceuticals U.S.A., Inc..

Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity

ObjectiveGlucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose homeostasis. The objective of this study was to determine whether activation of PPG neurons per se modulates glucose homeostasis and insulin sensitivity in vivo. MethodsWe generated glucagon (Gcg) promoter-driven Cre transgenic mice and injected excitatory hM3Dq-mCherry AAV into their brainstem NTS. We characterized the metabolic impact of PPG neuron activation on glucose homeostasis and insulin sensitivity using stable isotopic tracers coupled with hyperinsulinemic euglycemic clamp. ResultsWe showed that after ip injection of clozapine N-oxide, Gcg-Cre lean mice transduced with hM3Dq in the brainstem NTS downregulated basal endogenous glucose production and enhanced glucose tolerance following ip glucose tolerance test. Moreover, acute activation of PPG neuronsNTS enhanced whole-body insulin sensitivity as indicated by increased glucose infusion rate as well as augmented insulin-suppression of endogenous glucose production and gluconeogenesis. In contrast, insulin-stimulation of glucose disposal was not altered significantly. ConclusionsWe conclude that acute activation of PPG neurons in the brainstem reduces basal glucose production, enhances intraperitoneal glucose tolerance, and augments hepatic insulin sensitivity, suggesting an important physiological role of PPG neurons-mediated circuitry in promoting glycemic control and insulin sensitivity.

Capparis spinosa L. aqueous extract evokes antidiabetic effect in streptozotocin-induced diabetic mice.

As the aqueous extract of Capparis spinosa (CS) possess antidiabetic effect, he present study aims to reveal the possible mechanism of action of CS in diabetic mice. Both single and repeated oral administrations of aqueous extract of CS were performed in multi-low dose streptozotocin-induced (MLDS) diabetic mice. Euglycemic hyperinsulinemic clamp was used in association with the endogenous glucose production (perfusion rate of 3-3H glucose) to evaluate the effect of CS aqueous extract on insulin sensitivity. Our study showed that aqueous extract of CS possess a potent hypoglycaemic activity in MLDS diabetic mice. Furthermore, the analysis perfusion of 3-3H glucose demonstrated the parallel decrease of basal endogenous glucose production (EGP) with the hypoglycaemic activity. EGP was lower in CS-Treated group when compared to the control group (p<0.001). The euglycemic hyperinsulinemic clamp technique demonstrated that CS treatment improves insulin sensitivity in peripheral tissues. We conclude that the antihyperglycemic effet CS is probably due to the inhibition of basal endogenous glucose production and the improvement of insulin sensitivity in MLDS diabetic mice.