Plasma Glucagon Levels Research Articles

Hyperglucagonemia in youth is associated with high plasma free fatty acids, visceral adiposity, and impaired glucose tolerance.

To delineate potential mechanisms for fasting hyperglucagonemia in childhood obesity by studying the associations between fasting plasma glucagon concentrations and plasma lipid parameters and fat compartments. Cross-sectional study of children and adolescents with obesity (n = 147) and lean controls (n = 43). Differences in free fatty acids (FFAs), triglycerides, insulin, and fat compartments (quantified by magnetic resonance imaging) across quartiles of fasting plasma glucagon concentration were analyzed. Differences in oral glucose tolerance test (OGTT) glucagon response was tested in high vs low FFAs, triglycerides, and insulin. Human islets of Langerhans were cultured at 5.5 mmol/L glucose and in the absence or presence of a FFA mixture with total FFA concentration of 0.5 mmol/L and glucagon secretion quantified. In children with obesity, the quartile with the highest fasting glucagon had higher insulin (201 ± 174 vs 83 ± 39 pmol/L, P < .01), FFAs (383 ± 52 vs 338 ± 109 μmol/L, P = .02), triglycerides (1.5 ± 0.9 vs 1.0 ± 0.7 mmol/L, P < .01), visceral adipose tissue volume (1.9 ± 0.8 vs 1.2 ± 0.3 dm3 , P < .001), and a higher prevalence of impaired glucose tolerance (IGT; 41% vs 8%, P = .01) than the lowest quartile. During OGTT, children with obesity and high insulin had a worse suppression of glucagon during the first 10 minutes after glucose intake. Glucagon secretion was 2.6-fold higher in islets treated with FFAs than in those not treated with FFAs. Hyperglucagonemia in childhood obesity is associated with hyperinsulinemia, high plasma FFAs, high plasma triglycerides, visceral adiposity, and IGT. The glucagonotropic effect of FFAs on isolated human islets provides a potential mechanism linking high fasting plasma FFAs and glucagon levels.

383-P: The Potential Role of Il-6 in Defective Glucose Sensing following Recurrent Hypoglycaemia

Hypoglycaemia is common in insulin-treated therapy in the management of type 1 and long duration type 2 diabetes. Hypoglycemia evokes a significant stress response stimulating the release of several inflammatory mediators including interleukin 6 (IL-6). Importantly, glial cells also release IL-6 in response to glucose deprivation. We have previously demonstrated a role for IL-6 in the induction of defective neuronal glucose sensing in vitro. Here we investigate the potential role of IL-6 in the development of defective counter-regulatory response (CRR) to hypoglycaemia in vivo. IL-6Ra-/- mice were generated by crossing IL-6RaFlx/flx with Nestin-Cre+/-animals. Male IL-6Ra-/- and Cre+/- animals (Control) 18 weeks old, n=10/12 per group) were fed standard laboratory chow for 20 weeks. Hormonal response to hypoglycaemia was assessed in vivo by hyperinsulinaemic-hypoglycaemic clamps. Plasma epinephrine and glucagon were measured by ELISA in response to either acute (single hypo; AH) or recurrent (3 episodes per week for 4 weeks; RH) hypoglycaemia. Data are expressed as mean±SEM. The epinephrine response to hypoglycaemia was significantly elevated (&amp;gt;3 fold higher) in male IL-6Ra-/- animals following AH when compared to their control counterparts (0.38±0.09 vs. 1.31±0.28 delta; p&amp;lt;0.05). Plasma glucagon levels were comparable between genotypes (p=ns). In contrast, there was a significant suppression of the CRR to hypoglycaemia in both Control and IL-6Ra-/- animals following RH. Indeed, both IL-6Ra-/- and Control animals had suppressed epinephrine (50% and 68% reduction) and glucagon (65% and 44% reduction) responses to following RH when compared to their non-RH counterparts. These findings highlight an important role for central IL-6 signaling in response to acute hypoglycemia, however, additional mechanisms appear to contribute to the development of defective CRR following RH. Disclosure A.D. McNeilly: None. J. Gallagher: None. R.J. McCrimmon: Advisory Panel; Self; Eli Lilly and Company, Novo Nordisk A/S, Sanofi-Aventis. Research Support; Self; The Leona M. and Harry B. Helmsley Charitable Trust. Funding Diabetes UK

1435-P: Impaired Early-Phase Suppression of Glucagon Secretion after Glucose Load Associated with Insulin Need during Pregnancy in Gestational Diabetes

Aims: The prevalence of gestational diabetes mellitus (GDM) has recently increased all over the world. It is hard to predict insulin need during pregnancy even if the insulin secretory capacity is evaluated when studying 75-g OGTT to screen for GDM. The role of glucagon abnormality has remarked in pathogenesis of type 2 diabetes, however, still unknown in GDM. This study was aimed to evaluate glucagon responses in GDM and to investigate whether measurement of glucagon is useful to anticipate insulin need during pregnancy. Methods: Forty-nine women diagnosed with GDM based on IADPSG criteria were enrolled into the study and re-studied OGTT during mid-gestation to evaluate glucagon responses. Plasma glucagon levels were measured before and 30, 60, 120 min after glucose load using a sandwich ELISA kit. Insulin treatment was initiated when either a fasting glucose &amp;gt;95 mg/dL or postprandial 2-h glucose &amp;gt;120 mg/dL continues for more than a week after starting diet therapy. Results: Of 49 patients, fifteen were required insulin (defined as GDM/Insulin) and 34 could be treated with diet therapy alone until delivery (defined as GDM/Diet). GDM/Insulin was started insulin treatment at 29.6±3.6 weeks of gestation and the maximum insulin dose was 39.0±24.8 units/day. There were no significant differences in maternal age, pre-gravid BMI and insulin secretory responses during OGTT between the groups. Although fasting glucagon levels were not different between the groups, paradoxical increases in early-phase glucagon secretion after glucose load were observed in GDM/Insulin but not in GDM/Diet. The changes in glucagon levels (pg/mL) from 0 min to 30 min were significantly different between the groups (1.3±8.1 in GDM/Insulin vs. -4.2±4.0 in GDM/Diet, p&amp;lt;0.01), and the ROC analysis of the value to predict insulin need was -2.01 pg/mL. Conclusions: Impaired early-phase glucagon suppression might be useful to predict for insulin need during pregnancy in GDM. Disclosure I. Horie: None. A. Haraguchi: None. N. Abiru: None. A. Kawakami: None.

1967-P: Mild Physiologic Hyperglycemia Impairs Insulin-Mediated Suppression of Plasma Glucagon in Healthy Normal Glucose Tolerant Subjects

Hyperglycemia adversely affects skeletal muscle and hepatic insulin sensitivity (glucotoxicity). However, the effect of prolonged hyperglycemia on glucose and insulin-mediated suppression of glucagon is not known. The aim of the present study was to evaluate effect of a chronic (72 hours) physiologic increase (+45 mg/dl) in plasma glucose concentration on the suppression of plasma glucagon concentration in healthy NGT individuals: 12 without family history of T2DM (FH-) (9M/3F, age = 50± 4 years, BMI = 27 ± 1 kg/m2) and 8 with FH of T2DM (FH+) (4M/4F, age = 48±2, BMI = 26±1 kg/m2). Subjects received an OGTT and 2-step hyperglycemic (+125 and +300 mg/dl) clamp (duration of each step = 80 minutes) before and after 72-hour glucose infusion. Plasma insulin and C-peptide concentrations were obtained every 2-5 minutes during each hyperglycemic clamp step and plasma glucagon concentrations were measured every 10 minutes. The ratio of insulin/glucagon was measured and used as an index of insulin-medicated suppression of plasma glucagon. FPG concentration increased from 97±4 to 140±4 mg/dl during the 72-hour glucose infusion. Following chronic glucose infusion, plasma insulin levels were significantly higher during the basal state and during each hyperglycemic clamp step (by 59% and 78%) during the 0-80 and 80-160 min time periods, respectively. There was no difference in plasma glucagon levels following chronic glucose infusion. However, the plasma insulin/glucagon ratio was significantly higher during the fasting state (by 76%) and during the first (by 128%) and second (by 178%) hyperglycemic clamp steps. There was no difference in the effect of chronic glucose infusion on glucagon secretion between FH+ and FH-subjects. These results demonstrate that sustained physiologic hyperglycemia for 72 hours (i.e., glucotoxicity) impairs insulin-mediated suppression of glucagon, and could contribute to fasting and post-prandial hyperglycemia in T2DM patients. Disclosure A. Merovci: None. X. Chen: None. 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's Bureau; Self; AstraZeneca, Novo Nordisk Inc. D. Tripathy: None. Funding National Institutes of Health

2128-P: Exploring the Role of Autophagy in Pancreatic Alpha Cells

Autophagy is known to play a pivotal role in intracellular quality control through the degradation of subcellular damaged organelles and components. Whereas autophagy is essential for maintaining β-cell function in pancreatic islets, it remains unclear as to how the cellular autophagy affects the homeostasis and function of glucagon-secreting α cells. To analyze the role of autophagy in α cells, we generated a mutant mouse model lacking Atg7, a key molecule for autophagosome formation, specifically in α cells. Histological analysis demonstrated an increased number of glucagon-positive cells, with a multilayered structure, in the islets under Atg7 deficiency, although metabolic profiles, such as body weight, blood glucose and plasma glucagon levels, were comparable between Atg7-deficient mice and control littermates. Consistent with our previous findings that Atg7 deficiency suppressed β-cell proliferation, cellular proliferation was suppressed in Atg7-deficient α cells. These findings suggest that α-cell autophagy plays a role in maintaining α-cell mass and normal islet architecture, but appears to be dispensable for metabolic homeostasis. Disclosure M. Himuro: None. T. Miyatsuka: None. L. Suzuki: None. M. Miura: None. T. Katahira: None. H. Goto: None. Y. Nishida: None. S. Sasaki: None. Y. Fujitani: Research Support; Self; Takeda Pharmaceutical Company Limited. H. Watada: Research Support; Self; Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Kissei Pharmaceutical Co., Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk A/S, Pfizer Inc., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited, Teijin Pharma Limited. Speaker's Bureau; Self; Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk A/S, Ono Pharmaceutical Co., Ltd., Sanofi, Takeda Pharmaceutical Company Limited, Terumo Medical Corporation. Other Relationship; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Kowa Pharmaceutical Europe Co. Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Ono Pharmaceutical Co., Ltd., Sanwa Chemical Industry Co. Ltd., Takeda Pharmaceutical Company Limited. Funding Japan Society for the Promotion of Science

274-OR: Beta-Cell Dysfunction Is Associated with Impaired Insulin-Mediated Suppression of Glucagon in Obese Hispanic Americans

Recent studies have demonstrated an increase in the glucagon:insulin ratio in lean versus obese subjects. We assessed insulin-mediated suppression of plasma glucagon levels in 260 obese Hispanic Americans (59 NGT, HbA1c= 5.1±0.1%, BMI= 32.6±0.7; 109 Prediabetes, HbA1c= 5.8±0.1%, BMI= 33.8±0.5; 92 T2D, HbA1c= 7.3±0.2%, BMI= 34±0.5) with varying glucose tolerance. Subjects participated in a 2-h OGTT with measurement of plasma glucose, insulin, glucagon concentrations. During the OGTT, we quantitated insulin-mediated suppression of plasma glucagon concentration, Matsuda Index of insulin sensitivity, and the insulin secretion/insulin sensitivity (disposition) index using plasma C-peptide concentration. There was no difference in fasting plasma glucagon level between obese subjects with normal glucose tolerance (NGT), prediabetes, and type 2 diabetes (T2D). However, there was a progressive decrease in fasting glucagon:insulin ratio from NGT to prediabetes to T2D (8.71±0.72 vs. 6.92±0.53 vs. 5.66±0.41, P&amp;lt;0.01). During OGTT at 60 min, glucagon:insulin ratio increased from NGT to T2D (0.93±0.09 vs. 0.89±0.07 vs. 2.33±0.20, P&amp;lt;0.001), and the suppression of plasma glucagon (compared to basal value) was markedly decreased (10.3±3.4% vs. 9.3±1.9% vs. 2.5±2.8%, P&amp;lt;0.05). At 120 min (OGTT), glucagon:insulin ratio was increased in T2D versus NGT (1.28±0.17 vs. 2.0±0.20, P&amp;lt;0.01). The glucagon:insulin ratio was closely correlated with whole body insulin sensitivity and β-cell function during the fasting state (Matsuda Index, r= 0.51, P&amp;lt;0.001; Disposition Index, r= 0.30, P&amp;lt;0.001) and with Disposition Index during the OGTT at 60 and 120 min (r= -0.41, P&amp;lt;0.001; r= -0.21, P&amp;lt;0.01), respectively. Collectively, these findings indicate that insulin-mediated suppression of glucagon secretion is impaired with increasing severity of glucose intolerance in obese Hispanic Americans and is closely associated with insulin resistance and β-cell dysfunction. Disclosure X. Chen: None. E.R. Maldonado Corchado: None. A. Merovci: None. E. Case: None. D. Tripathy: None. 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's Bureau; Self; AstraZeneca, Novo Nordisk Inc.

200-OR: Role of Delta Cell Gpr120 in the Regulation of Islet Function and Glucose Control

Gpr120 is a long-chain fatty acid receptor expressed in pancreatic islets, where it inhibits the secretion of somatostatin (SST) by the δ cell. SST is a negative regulator of glucoregulatory hormone secretion. However, the precise role of Gpr120 in the regulation of insulin and glucagon secretion is still unclear, as well as the specific islet cell(s) type(s) involved. Objective: This study aimed at defining the role of pancreatic δ-cell Gpr120 signaling in the regulation of islet function and glucose homeostasis. Methods: Insulin and SST secretion was measured in isolated islets from WT, Gpr120 KO and Gpr40 KO mice in 1h static incubation in the presence of 2.8 or 16.7 mM glucose with or without synthetic (Compound A, Cpd A) or endogenous (alpha-linolenic, eicosapentaenoic or docosahexaenoic acid) Gpr120 agonists. Glucagon and SST secretion was measured after 1h static incubation in response to arginine with or without Cpd A. Cpd A was administered orally to WT male mice before an oral Glucose Tolerance Test or an Arginine Test, and blood glucose and insulin or glucagon plasma levels were measured. Results: In isolated islets from WT mice, activation of Gpr120 with either Cpd A or endogenous agonists dose-dependently inhibited glucose-stimulated SST secretion, and concomitantly increased glucose-stimulated insulin secretion. Cpd A also inhibited SST secretion and potentiated glucagon secretion in response to arginine in low glucose conditions. The effects of Cpd A were unaltered in Gpr40 KO islets but disappeared in Gpr120 KO islets. Oral administration of Cpd A improved glucose tolerance and potentiated both glucose-induced insulin secretion and arginine-induced glucagon secretion. Conclusion: The results demonstrate that Gpr120 activation in islets inhibits SST secretion, potentiates insulin and glucagon secretion, and improves glycemic control. Disclosure M.L. Croze: None. S. Granziera: None. K. Vivot: None. A. Szpigel: None. J. Ghislain: None. V. Poitout: None. Funding Société Francophone du Diabète; Montreal Diabetes Research Center; Natural Sciences and Engineering Research Council of Canada

Effects of Cinnamon Spice on Postprandial Plasma Levels of Glucose and Insulin in Healthy Participant with Normal Weight (FS15-04-19)

ObjectivesThe objective of this study is to investigate the effect of one time intake of cinnamon spice on the postprandial glucose tolerance and insulin secretion following consumption of a high glycemic index meal in normal weight and glucose tolerance individuals. MethodsSixteen healthy controls (BMI = 18.5–24.9 kg/m2 and fasting blood glucose (BG) < 100 mg/dL) aging 20–50 years, who typically consume a low fiber/polyphenol diet (beige diet) were recruited for this study. Recruitment of overweight/obese, prediabetic participants is not completed (no data presented). Participants consume a typical American breakfast containing 50 g of carbohydrates (1/3 cup of oatmeal and 1 cup 2% milk) with or without cinnamon (6 g) followed by 1-week washout and crossover to the opposite intervention. The blood samples were taken at fasting state and at 30, 60, 90, 120, 150 and 180 minutes after the meal. The main outcome measures included BG and insulin. The secondary outcome measures were C-peptide and glucagon. Cinnamon spice (Indonesia) was purchased at the local grocery store (McCormick®) and contains 3.9% proanthocyanin. The statistical significance was set at P < 0.05 using SPSS. ResultsConsumingcinnamon spice with the oatmeal significantly decreased the rate of glucose change from fasting state at 60 and 90 minutes after the meal by 37% and 31%, respectively. The peak postprandial BG and the areas under the curve (AUC) of glucose were also lowered by cinnamon compared to oatmeal alone but did not reach the significant levels. There was a trend towards significant decrease (21%, P = 0.08) in plasma insulin concentrations and a significant decrease in plasma C-peptide levels 30 minutes after ingestion of the meal with cinnamon. Cinnamon ingestion compared to oatmeal alone also significantly decreased plasma glucagon levels at 90 minutes after the meal test. ConclusionsOur results suggest that one time intake of cinnamon spice lowers the mean rate of glucose change following a high glycemic index meal in healthy individuals. Cinnamon also decreased plasma levels of insulin, C-peptide, and glucagon. Funding SourcesUCLA Center for Human Nutrition.

104-OR: Glucoregulatory Effects of Hypothalamic Glucocorticoid Action In Vivo

Diabetes is characterized by dysregulated glucose homeostasis that leads to hyperglycemia, due in part to increased hepatic glucose production (GP) and insulin resistance. Excessive levels and/or action of glucocorticoids (GCs) are associated with obesity, insulin resistance, and hyperglycemia. We aim to delineate a mechanism of GC action in the mediobasal hypothalamus (MBH) that modulates GP in normal and pre-obese rodents. Male SD rats underwent stereotaxic MBH bilateral cannulation and intravenous (iv) and intraarterial catheterization to enable simultaneous direct infusions into the MBH, iv infusions, and blood sampling, respectively. Mildly hyperinsulinemic-euglycemic clamps with tracer dilution methodology combined with MBH GC infusion ± GC receptor (GR) inhibition enables measurement of GP and utilization while assessing MBH GC interaction with its MBH receptors independent of changes in plasma insulin, glucagon, and glucose levels. MBH GC infusion potently stimulates GP and lowers the requirement for exogenous glucose infusion without altering glucose utilization. This effect is mediated via GRs since co-infusion of GR antagonist mifepristone, or a HSP90 inhibitor, negates the ability of MBH GCs to increase GP. MBH GCs similarly increased glucose excursions during iv glucose tolerance tests, which was reversed with concomitant MBH mifepristone infusion. Rats fed with high fat diet (HFD) for 3 days had altered glucose kinetics and increased basal plasma corticosterone, insulin, and blood glucose levels without changes in body weight. Chronic MBH GR inhibition with MBH GR shRNA lowered GP compared to MBH mismatch control HFD rats with MBH vehicle infusions, suggesting that blocking excessive MBH GC action resulting from HFD-feeding attenuates GP to improve glucose homeostasis. We provide novel evidence that MBH GC action modulates GP in healthy and pre-obese rats. Importantly, targeted inhibition of MBH GC action may help improve glucose regulation in obesity-related metabolic disease. Disclosure E. Beaulieu-Bayne: None. M. Cardoso: None. H. Kim: None. S. Yang: None. J.T. Yue: None. Funding Diabetes Canada; Natural Sciences and Engineering Research Council of Canada; Alberta Diabetes Institute; Canadian Institutes of Health Research

1801-P: Common Hepatic Artery Denervation Does Not Alter the Counterregulatory Response to Hypoglycemia in an Insulin Resistant Canine Model

With the recent interest in sympathetic modulation as a way to improve insulin sensitivity and insulin secretion, it is important to assess the safety of the procedure. Five dogs were fed a high fat high fructose diet for 5-week before undergoing a hyperinsulinemic hypoglycemic clamp (insulin infused IV at a rate of 1.5 mU/kg/min). Then the dogs underwent a common hepatic artery surgical denervation (CHAD n=5) and were studied 1, 2 and 3 months post-surgery with the same hypoglycemic challenge. At the end of the protocol, the norepinephrine content in the liver (7±3 ng/g) and pancreas (91±34 ng/g) were significantly lower than levels in the livers and pancreas of 4 sham denervated animals (460±100 and 590±93 ng/g respectively), indicating successful denervation. There were no significant differences in fasting insulin, glucose or glucagon concentrations over the 3 months (see Table). The insulin and glucose concentrations during the last 90 min of the hypoglycemic challenge prior to and post-CHAD were also not different. The peak in plasma glucagon and epinephrine levels occurred at 30 and 120 min respectively and were similar in magnitude pre- and post-CHAD. Four sham denervated animals had the same response to the insulin induced hypoglycemic challenge as CHAD dogs. In conclusion, the response to hypoglycemia was not affected by sympathetic denervation of the common hepatic artery. Disclosure G. Kraft: Consultant; Self; Metavention. L. Moore: None. B. Farmer: None. M.F. Scott: None. D.S. Edgerton: Speaker's Bureau; Self; Novo Nordisk A/S. P.E. Williams: None. B. Azamian: Employee; Self; Metavention. A.D. Cherrington: Board Member; Self; Biocon, Fractyl Laboratories, Inc., Metavention, Sensulin, LLC., vTv Therapeutics, Zafgen, Inc. Consultant; Self; Abvance, Boston Scientific Corporation, California Institute for Biomedical Research, Galvani Bioelectronics Limited, MedImmune, Novo Nordisk Inc., Thetis Pharmaceuticals LLC. Research Support; Self; Abvance, Diasome Pharmaceuticals, Inc., Novo Nordisk Inc. Stock/Shareholder; Self; Abvance, Biocon, Fractyl Laboratories, Inc., Metavention, Novo Nordisk Inc., Sensulin, LLC., Thetis Pharmaceuticals LLC, Zafgen, Inc. Funding Metavention, Inc.

1860-P: Liver Fat and Visceral Fat Are Associated with Different Metabolic and Pathophysiologic Profiles but with Similar Relationships with Whole Body Insulin Resistance

MRI-based examinations of hepatic steatosis and body fat are becoming more familiar and useful for metabolic studies including NAFLD. MRI-estimated proton density fat fraction (MRI-PDFF) can haptic fat exactly without biopsy, enabling us to evaluate the effect of liver fat more sophisticatedly than ever. Although hepatic fat and visceral fats are both important for metabolic and cardiovascular diseases, detailed evaluation of the effect of each fat depot on various metabolic profiles have not been performed, In the present study, we evaluated the differential effect between hepatic and visceral fats on various metabolic profiles including glucose and lipid metabolism, islet cell function, insulin resistance, and inflammation. A total of 82 subjects (25 healthy volunteers and 57 patients with suspected, or proven NAFLD) who underwent MRI examinations for MRI-PDFF and visceral fat measurement. Additionally, anthropometric and laboratory studies and total body fat measurement by DXA were also performed. Other causes of chronic liver diseases, such as alcoholic, autoimmune or viral hepatitis, and other diseases, were excluded from the study. The amounts of hepatic fat and visceral fats measured by MRI showed similar significant correlations with HOMA-IR (r=0.540 vs. r=0.538, p &amp;lt;0.01, respectively) as with A1C (r=0.448 vs. r=0.495, p &amp;lt;0.01 each). However, hepatic fat showed more close association with FBS, triacylglycerol, complement factor C3, and cytokeratin 18. Visceral fat correlated more with fasting plasma insulin, glucagon and angiotensinogen levels. Total body fat measured by DXA did not show such characteristic patterns of correlations and showed only a weak or no correlation with those parameters. Thus, our results showed that both hepatic fat and visceral fat depots are important determinants of whole-body insulin resistance and glucose metabolism. Disclosure I. Park: None. K. Lee: None. D. Lee: None.

1723-P: Genetic Risk Scores Predict Glycemic Traits and Response to Glipizide Treatment in the Study to Understand the Genetics of the Acute Response to Metformin and Glipizide in Humans (SUGAR-MGH)

Whether genetics can help predict response to type 2 diabetes (T2D) drugs is unknown. We set out to examine whether genetic risk scores (GRSs) composed of single nucleotide polymorphisms (SNPs) known to be associated with glycemic traits and T2D are associated with glycemic traits and the acute response to metformin and glipizide in SUGAR-MGH. We measured plasma glucose, insulin, glucagon, proinsulin, c-peptide, GLP-1, and GIP levels in 1,000 participants naïve to antidiabetes medications at 0, 30, 60, 90, 120, 180, and 240 minutes following administration of 5 mg glipizide (Visit 1, day 1), and during a 75-g oral glucose tolerance test following a short metformin course (Visit 2, day 8). We constructed a T2D, fasting glucose (FG), and fasting insulin (FI) GRS (with 65, 43 and 13 SNPs respectively) by summing the number of risk alleles carried by each person based on known genome-wide significant associations. Linear regression tested for associations between GRSs and glycemic traits as well as pharmacodynamic endpoints, adjusting for age, sex, race, and BMI. The FG GRS predicted FG in our cohort (β=0.46 increase in FG in mg/dL*allele, P&amp;lt;0.001). The FI GRS predicted fasting insulin (β=0.02 increase in ln FI in µU/mL*allele, P=0.04). A higher T2D GRS was associated with a shorter time to insulin peak, greater glucose area over the curve, shorter time to glucose trough, and steeper slope to glucose trough (P&amp;lt;0.05) after glipizide administration, indicating a stronger response. When we set a more stringent P-value of 0.008 to correct for multiple comparisons, the FG GRS remained associated with FG and the T2D GRS remained associated with the insulin-based endpoint. We conclude that established genetic determinants of glycemic traits predict FG and FI in our cohort of individuals free of overt diabetes; moreover, T2D risk alleles may predispose individuals to a greater insulin response to glipizide treatment. Disclosure J.H. Li: None. L. Szczerbinski: None. V. Kaur: None. J. Todd: None. J.C. Florez: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (R01DK-088214, R03DK-077675, P30-DK-036836); Joslin Clinical Research Center; Harvard Catalyst; National Center for Research Resources/National Center for Advancing Translational Sciences (M01-RR-01066, 1UL1-RR-025758-04, 88UL1-TR-000170-05; Harvard University

14-LB: Somatostatin Receptor 2 Antagonism Enhances Plasma Glucagon Levels during Insulin-Induced Hypoglycemia in a Rodent Model of Type 2 Diabetes Mellitus

Somatostatin Receptor 2 antagonists (SSTR2a) increase glucagon counter-regulation to hypoglycemia in various rodent models of type-1 diabetes mellitus. Here we investigated the efficacy of SSTR2a in improving glucagon counter-regulation in a rat model of type-2 diabetes mellitus (T2DM). For this, male Sprague Dawley rats (n=18) were given a high fat diet for 3 weeks, followed by low-dose streptozotocin exposure (35 mg/kg, IP) to induce T2DM. Rats were then divided into SSTR2a treatment (PRL-2903, 10 mg/kg) or vehicle (n=9 for each) 1-hour before insulin-induced hypoglycemia (3 IU/kg NovoRapid). This process was repeated 1 week later in a cross-over design, with the data pooled over SSTR2a and vehicle treatments. A group of normal-chow-fed rats (n=3) served as nondiabetic controls. Mean blood glucose levels were higher at 20, 30, 40, and 50 minutes post insulin administration in the T2DM rats treated with PRL-2903, as compared to vehicle (p ≤ 0.05). The number of T2DM rats that developed biochemical hypoglycemia (blood glucose ≤ 3.5 mmol/L) tended to be less with PRL-2903 (5/18) vs. vehicle (9/18). Compared with vehicle treatment, PRL-2903 promoted higher plasma glucagon counter-regulation, as indicated by area under curve (AUC) analysis (p &amp;lt; 0.05). Thus, SSTR2a treatment improves the attenuated glucagon response to hypoglycemia in T2DM rats. Disclosure M. Nejad-Mansouri: None. P. Zaree Bavani: None. J. Aiken: None. N.C. DSouza: None. E.G. Hoffman: None. R. Liggins: None. M. Riddell: Advisory Panel; Self; Xeris Pharmaceuticals, Inc. Research Support; Self; Dexcom, Inc. Speaker’s Bureau; Self; Insulet Corporation, Medtronic MiniMed, Inc. Stock/Shareholder; Self; Zucara Therapeutics Inc. Funding National Research Council Canada; Zucara Therapeutics

193-OR: Glycemic Control via Glucagon Modulation by a Novel Brown Adipose Peptide Hormone

Subcutaneous transplants of embryonic brown adipose tissue (BAT) lead to euglycemia without insulin in mouse models of T1D [Diabetes 2012 61:674]. Euglycemia is accompanied by normalized plasma glucagon levels, restored healthy white adipose tissue, reduced inflammatory cytokines, and increased anti-inflammatory adipokines. Elevated IGF-1 was shown to play a role in successful transplants, putatively by direct stimulation of the insulin receptor [Am. J. Physiol. Endocrinol. Metab. 2015 308:E1043]. However, the mechanism underlying this effect remained unknown. We hypothesized that a secreted product from the transplanted BAT communicates with the recipient allowing a new metabolic equilibrium in the absence of insulin. We tested this using buffer conditioned by cultured immortalized BAT cells. We injected this buffer into diabetic NOD mice once daily for 7 consecutive days. In 5 of the 9 animals studied, blood glucose levels dropped back to the normal range (∼150 mg/dl) for at least 2 months with one animal remaining euglycemic for 5 months with no further intervention. As in embryonic BAT transplants, conditioned buffer injections led to a rapid decrease in plasma glucagon. We found that applying this conditioned buffer to isolated mouse and human islets lowers glucagon secretion directly (without significant changes in insulin or somatostatin). To purify and identify the active BAT-secreted compound, we established a multi-step fractionation protocol using size exclusion, ion exchange, and hydrophobicity columns to concentrate the active compound ∼10 million-fold over the initial BAT-conditioned buffer. Protease, denaturation, and spectroscopy experiments revealed a modified peptide of ∼1600 Da. Initial screening of GPCR targets [Nat Struct Mol Biol. 2015 22:362] revealed binding to the μ-opioid receptor, which is expressed preferentially in α-cells within the islet of Langerhans. Thus, these data suggest a novel path towards clinical antagonism of glucagon secretion. Disclosure D.W. Piston: Consultant; Self; Pfizer Inc. A. Ustione: None. S.C. Gunawardana: None. J. Hughes: None. Funding National Institutes of Health (DK098659); The Leona M. and Harry B. Helmsley Charitable Trust

327-LB: Transgenic Overexpression of MicroRNA-30d Impairs Glucose Homeostasis by Regulating Beta-Cell Proliferation and Dedifferentiation

MicroRNAs (miRNAs) are small non-coding RNAs that bind to target mRNAs and inhibit the translation in mammals. Abnormal miRNA functions are closely associated with pancreatic beta-cell loss and dysfunction in type 2 diabetes. Downregulation of miR-30d has been observed in the islets of diabetic mice. To investigate the in vivo function of miR-30d in pancreatic beta cells, we generated the transgenic mice that overexpressed miR-30d specifically in the pancreatic beta cells. Compared to wild type mice, the transgenic mice that overexpressed miR-30d resulted in hyperglycemia and glucose intolerance with reduced beta-cell mass and insulin production following high fat diet treatment. Strikingly, loss of beta-cell mass was partially due to beta-cell dedifferentiation to glucagon-producing alpha-cells, resulted in increased plasma glucagon level. The transcriptomic analysis combined with bioinformatic analysis of islets isolated from transgenic verses control mice identified connective tissue growth factor (CTGF) and Cyclin E2 as miR-30d potential targets. Moreover, several β-cell disallowed genes (e.g., MCT4/SLC16A3, LDHA) were observed upregulated in transgenic mice, which have been reported as positive markers of dedifferentiated human β-cells from type 2 diabetic patients. Taken together, miR-30d plays an essential role in maintaining mature beta-cell identity. Disclosure X. Tang: None. Funding National Institutes of Health

Antagonistic Glucagon Receptor Antibody Promotes α-Cell Proliferation and Increases β-Cell Mass in Diabetic Mice

SummaryUnder extreme conditions or by genetic modification, pancreatic α-cells can regenerate and be converted into β-cells. This regeneration holds substantial promise for cell replacement therapy in diabetic patients. The discovery of clinical therapeutic strategies to promote β-cell regeneration is crucial for translating these findings into clinical applications. In this study, we reported that treatment with REMD 2.59, a human glucagon receptor (GCGR) monoclonal antibody (mAb), lowered blood glucose without inducing hypoglycemia in normoglycemic, streptozotocin-induced type 1 diabetic (T1D) and non-obesity diabetic mice. Moreover, GCGR mAb treatment increased the plasma glucagon and active glucagon-like peptide-1 levels, induced pancreatic ductal ontogenic α-cell neogenesis, and promoted α-cell proliferation. Strikingly, the treatment also increased the β-cell mass in these two T1D models. Using α-cell lineage-tracing mice, we found that the neogenic β-cells were likely derived from α-cell conversion. Therefore, GCGR mAb-induced α- to β-cell conversion might represent a pre-clinical approach for improving diabetes therapy.

Positive correlation between fasting plasma glucagon and serum C-peptide in Japanese patients with diabetes

AimsGlucagon plays pivotal roles in systemic glucose homeostasis mainly by promoting hepatic glucose output. Using a sandwich enzyme-linked immunosorbent assay (ELISA), we evaluated fasting plasma glucagon levels in hospitalized patients with type 1 or type 2 diabetes, and assessed the relationships between glucagon levels and various clinical parameters. MethodsWe enrolled adult Japanese diabetes patients admitted to Osaka University Medical Hospital for glycemic control between July 2017 and May 2018 in this study. After patients had fasted for 12 h, blood samples were obtained and plasma glucagon levels were measured using a sandwich ELISA. ResultsTotal 107 patients participated in the study. The mean fasting plasma glucagon level of patients with acute onset type 1 diabetes was significantly lower than that of patients with type 2 diabetes (p < 0.05). Plasma glucagon levels were not significantly correlated with plasma glucose levels in patients with type 1 diabetes or in patients with type 2 diabetes. Multiple regression analysis indicated that fasting glucagon levels were independently and significantly correlated with fasting serum C-peptide levels in patients with type 2 diabetes. ConclusionsOur results suggest that insulin and glucagon secretion are balanced in the fasting state in patients with type 2 diabetes.

An Intraperitoneal Treatment with Calcitonin Gene-Related Peptide (CGRP) Regulates Appetite, Energy Intake/Expenditure, and Metabolism.

Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide expressed both centrally and peripherally. CGRP has been shown to be involved in arteriolar dilation, cardiovascular regulation, pain transmission, migraine, and gastrointestinal physiology. Our current research is aimed at analyzing CGRP's impact on appetite/satiety, body metabolism, and energy homeostasis. Our study investigated the effects of a single-dose intraperitoneal (IP) treatment with CGRP on food and water consumption, energy expenditure, physical activity, respirometry, and a panel of plasma metabolic hormones in C57Bl/6 wild-type (WT) mice. After a CGRP IP injection at a dose of 2nmol (10μM CGRP in 200μl of saline), a significant reduction in food intake and metabolic parameters as RQ, VCO2, and VO2 was observed. CGRP-injected mice had also significantly lower total energy expenditure (TEE) with no changes in activity levels compared to vehicle-injected controls. CGRP treatment in mice induced significantly lower plasma levels of glucagon and leptin but higher levels of amylin. Our data show that a single dose of CGRP peptide significantly decreased food consumption and altered calorimetric parameters and plasma metabolic hormone levels, thus confirming that CGRP plays a pivotal role in the regulation of appetite and metabolism. Future studies are necessary to analyze CGRP's long-term impact on body metabolism and its potential effects on appetite, obesity, and metabolic disorders.

Relationship Between Fasting Plasma Glucagon Level and Renal Function-A Cross-Sectional Study in Individuals With Type 2 Diabetes.

Background and AimThe kidney is the main site for glucagon clearance. However, a recent study showed that hyperglucagonemia in patients with end-stage renal disease might not be caused by full-length intact glucagon. Additionally, the relationship between glucagon and renal function in early-stage chronic kidney disease (CKD) has not yet been characterized. We studied the association of fasting glucagon with renal function across a wide range of glomerular filtration rates (GFRs) in participants with type 2 diabetes.Participants and Methods326 participants with type 2 diabetes and renal function spanning CKD stage 1 to 5 were included in the present cross-sectional study. Fasting full-length plasma glucagon was quantified using a newly developed ELISA (Mercodia AB, Uppsala, Sweden).ResultsThe fasting plasma glucagon level was elevated linearly from CKD stage 1 to 5 [from a median of 2.5 pM (interquartile range, 1.4 to 4.7) in CKD 1 to a median of 8.3 pM (interquartile range, 5.9 to 12.8) in CKD 5; P for trend < 0.0001], from as early as CKD stage 2 compared with that in stage 1 (Bonferroni-corrected P < 0.0001). The estimated GFR and homeostatic model of assessment–insulin resistance were the main determinants of the fasting glucagon level. These explained 14.3% and 10.3% of the glucagon variance, respectively. Albuminuria was not associated with fasting glucagon after adjustment for estimated GFR.ConclusionsFasting full-length glucagon was elevated linearly with the deterioration in renal function in individuals with type 2 diabetes, even in those with early CKD. In addition to renal function, insulin sensitivity was also a main determinant of glucagon variance.

A retrospective study of 14 cases of glucagonoma with literature review

Objective To improve the clinical understanding of glucagonoma. Methods A total of 14 cases of glucagonoma were admitted to our hospital, and the clinical features of these cases were retrospectively analyzed. Results (1) The female/male case ratio was 1∶1. (2) The median age of onset was 47 years (range 33-61), while the median age at diagnosis was 50 years (range 33-64). (3) The most common initial presentation was necrolytic migratory erythema (7/14, 50%). (4) Hyperglycemia was the most common presentation at the time of diagnosis (14/14, 100%), followed by necrolytic migratory erythema (13/14, 92.9%). (5) The misdiagnosis rate before admission to our hospital was as high as 85.7% (12/14), and the most common misdiagnosis was eczema (7/12, 58.3%). (6) The median time from onset of probable symptoms to diagnosis was 4 years. (7) The median plasma glucagon level at diagnosis was 798 pg/ml (range 200-2 853). (8) The median length of the longest tumor diameter of the pancreatic tumors at diagnosis was 4.0cm (range 2.2-8.0). (9) 57.1% of primary pancreatic glucagonomas localized in the tail of the pancreas. (10) 57.1% of patients (8/14) had metastases at the time of diagnosis. Conclusions (1)Necrolytic migratory erythema is a relatively sensitive and specific symptom for diagnosis of glucagonoma. (2)The diagnosis for glucagonoma was often delayed, and misdiagnosis was common. (3)Most glucagonoma patients had metastases at the time of diagnosis. (Chin J Endocrinol Metab, 2018, 34: 909-914) Key words: Glucagonoma; Necrolytic migratory erythema; Diabetes mellitus; Neuroendocrine tumor.