Serum Glucagon Levels Research Articles

20-OR: GPR142 Agonists Increase Glucose-Dependent Insulin Secretion and Differentially Regulate Hormone Secretion in Preclinical and Phase 1 Studies

Agonists of G-protein-coupled receptor 142 (GPR142) are reported to increase insulin secretion and lower glucose in preclinical models. We identified a novel agonist, LY3325656 (LY) that selectively activates GPR142 in humans and mice. In preclinical models, LY increased glucose-dependent insulin secretion (GDIS) and secretion of glucagon and incretin hormones GLP-1 and GIP. To elucidate mechanisms of LY in humans, we designed a multi-part, single-dose study in 24 healthy volunteers (HV) and 12 patients with type 2 diabetes (T2D) (NCT03115099). LY was well tolerated through dose escalation up to 1950 mg in HV, with a median time to peak concentration of 4 hours and half-life of 4.59 hours. A graded glucose infusion evaluated GDIS, and LY demonstrated increased insulin secretion at higher doses (750-1950 mg). A 4-period, crossover design consisting of placebo (Pb), LY (1950mg), LY+DPP-IV inhibitor, and GLP-1R agonist treatment investigated glucose-lowering and incretin pharmacology in patients with T2D. LY significantly reduced post-meal glucose levels (2-hour glucose AUC) by >10% during a mixed meal tolerance test. Increases in post-meal GLP-1 AUC concentrations with LY compared to Pb were seen in a few, but not all patients with T2D. Serum glucagon levels were consistently increased by LY in patients with T2D and HV. We conclude that GPR142 activation in humans increases GDIS and augments glucagon secretion but does not substantively augment GIP or GLP-1 secretion. Our data suggest that acute stimulatory effects of GPR142 on insulin and glucagon secretion translate from preclinical models to man, unlike preclinical effects on gut peptide secretion. Innovative and efficient single-dose studies can provide key mechanistic understanding of the translatability of preclinical findings for the treatment of T2D. Disclosure E.J. Pratt: Employee; Self; Eli Lilly and Company. T. Oura: Employee; Self; Eli Lilly and Company. Stock/Shareholder; Self; Eli Lilly and Company. X. Ma: Employee; Self; Eli Lilly and Company. H.V. Lin: Employee; Self; Eli Lilly and Company, Forkhead BioTherapeutics, Inc. Employee; Spouse/Partner; Novo Nordisk A/S. Stock/Shareholder; Self; Eli Lilly and Company, Forkhead BioTherapeutics, Inc. Stock/Shareholder; Spouse/Partner; Novo Nordisk A/S. T. Ma: None. A.M. Efanov: Employee; Self; Eli Lilly and Company. M.K. Thomas: Employee; Self; Eli Lilly and Company. Stock/Shareholder; Self; Eli Lilly and Company.

2187-P: Gsα Deficiency in Pancreatic a Cells Leads to Enlarged Islets

Pancreatic β-cell dysfunction leads to diabetes with reduced β-cell mass and impaired glucose-stimulated insulin secretion. The G protein α subunit Gsα couples receptors to generate cAMP, which mediates the insulinotropic effects of incretin hormones, such as GLP-1. We previously reported that β-cell-specific Gsα deficiency causes insulin-deficient diabetes due to reduced islet size and β-cell mass, and that mice with whole pancreatic Gsα deficiency develop insulin deficient diabetes and reduced β-cell mass, but also showed increased proliferation of α-cells, indicating that Gsα plays divergent roles in pancreatic α-and β-cell growth. In the present study, we generated mice with α-cell-specific Gsα deficiency (αGsKO) by mating Gsα-floxed mice with glucagon-cre mice and studied the metabolic consequences. Deletion of Gsα in α-cells did not affect growth, blood glucose, or serum insulin or glucagon levels. However, αGsKO mice displayed enlarged islet size of normal architecture with significant increases in both α- and β-cell numbers, accompanied with increased β-cell proliferation and reduced apoptosis. This increased β-cell proliferation could be detected as early as at 3 days after birth. Consistent with this, αGsKO mice showed increased insulin response to acute glucose loading (3mg/g i.p.), although they had unaltered glucose tolerance when given a lower dose of glucose (2 mg/g i.p.). The results of RT-PCR on pancreatic islets isolated from aged mice (9-10 months old) showed that expression of Maf B and Pax6, transcription factors required for β-cell development, tended to be increased; whereas cell cycle factors, such as Cyclin D1, D2, and CDK4, tended to be decreased. Taken together, our results show that Gsα/cAMP signaling pathway in pancreatic α-cells is critical for both α- and β-cell growth as well as for maintenance of β-cell mass. Disclosure A. Taira: None. H. Sun: None. C. Le: None. O. Gavrilova: None. M. Chen: None. L. Weinstein: None. Funding National Institutes of Health

198-OR: Role for the Cationic Amino Acid Transporter Slc7a2 in Alpha-Cell Proliferation and Islet Hormone Secretion

Interrupting glucagon receptor signaling results in hyperaminoacidemia, which stimulates alpha cell hyperplasia. Arginine, a potent secretagogue for both insulin and glucagon, is required for hyperaminoacidemia-stimulated alpha cell proliferation. To investigate the role of arginine transport, we compared the expression of amino acid transporters in published datasets of sorted mouse and human islet cells and found that Slc7a2, cationic amino acid transporter, is the most highly expressed amino acid transporter in both mouse and human alpha cells and that its expression is three-fold higher in alpha cells than in beta cells. Following glucose/arginine injection, global Slc7a2 knockout mice (Slc7a2-/-) had 20% higher blood glucose (+/+ vs. -/-: 412±23 vs. 517±25mg/dL, n=11-12, p=0.004), 80% lower serum insulin (3.7±0.6 vs. 0.7±0.4nM, p=0.0008) and 59% lower serum glucagon (64.3±23.1pM vs. 26.3±11.4pM, p=0.009) than Slc7a2+/+ animals. Slc7a2+/- mice had 55% decreased insulin levels (+/+ vs. +/-: 3.7±0.6 vs. 1.7±0.3nM, n=8, p=0.012), but showed no difference in serum glucose or glucagon levels, indicating that Slc7a2 expression may be rate limiting for beta cell, but not alpha cell, function. Isolated islets from Slc7a2-/- mice had normal morphology, but reduced high amino acid-stimulated alpha cell proliferation by 90% and 58% in Slc7a2-/- and Slc7a2+/- islets, respectively (+/+ vs.-/-: 3.7±1.7 vs. 0.4±0.2%, p=0.007, n=4; +/+ vs. +/-: 3.7±1.7 vs. 1.5±0.6%, p=0.038, n=4). Knockdown with Slc7a2 shRNA in the aTC1-6 mouse alpha cell line also decreased proliferation. Taken together, these data indicate a central role for Slc7a2 in amino acid-stimulated alpha cell proliferation and glucagon and insulin secretion. Disclosure E. Spears: None. M. Shou: None. W.A. Siv: None. C. Dai: None. W. Chen: None. A.C. Powers: None. D. Dean: None.

386-P: Chronic and Acute Consumption of a Ketogenic Diet Leads to Deficits in Hypoglycemic Counterregulation in Mice

Background: Due to their metabolic benefits, ketogenic diets (KDs) are growing increasingly popular as a dietary strategy for augmenting treatment of type 1 and type 2 diabetes. Although much is known regarding the metabolic benefits of KDs, little is known about their effect on hypoglycemic counter-regulation. We tested whether mice fed a KD have normal hypoglycemic counter-regulation. Methods: B6 mice were fed a KD (Bio-Serv; F3666) ad lib for either 28 days (chronic) or 7 days (acute). On the final day of the diet, hypoglycemic counter-regulation was assessed via glucoprivic challenge (ICV 2DG, 1 mg/mouse, or saline) in the chronic KD group or via a hypoglycemic insulin tolerance test (ITT) in the acute KD group. Deficits in the counter-regulatory response were determined by comparing glucose and glucagon levels to control mice simultaneously fed a standard chow diet (LabDiet; 5001). ITTs consisted of a variable dose of IP insulin which produced equivalent hypoglycemia in all groups (∼45 mg/dL). Results: As expected, mice fed a KD either acutely or chronically had lower fasting blood glucose levels relative to controls (chronic KD: 132.4 and 167.5mg/dL respectively, p = 0.0011, n= 12-17/group; Acute KD: 167.3 and 200.7 mg/dL respectively, p = 0.026; n = 7-10/group). In response to glucoprivic challenge, chronic KD mice had a blunted rise in both glucose and glucagon relative to chow fed mice (Delta glucose: 84.2 and 135.8 mg/dL respectively, p = 0.017; Glucagon: 32.7 and 73.8 pg/mL respectively, p = 0.027; n = 5-8/group). Acute KD mice also had reduced serum glucagon levels in response to the ITT (28.8 and 50.1 pg/mL respectively, p = 0.044). Conclusions: We show that consuming a KD reduces glucose counter-regulation in mice. If a similar effect exists in persons with diabetes it could blunt a homeostatic response which is critical for counteracting treatment-induced hypoglycemic crises. Further characterization of the effects of KDs on glucose counter-regulation is warranted. Disclosure M.A. DuVall: None. C. Coulter: None. C.M. Hill: None. C. Morrison: None. H.X. Sikaffy: None. D. McDougal: None. Funding American Diabetes Association (1-15-JF-37 to D.M.)

Alcohol Intoxication and the Postburn Gastrointestinal Hormonal Response

Gastrointestinal hormones are essential in postburn metabolism. Since near 50% of burn victims test positive for blood alcohol levels at hospital admission and have inferior outcomes compared to nonintoxicated burn patients; we hypothesized that the gastrointestinal hormone secretion is compromised in intoxicated burn victims. To test our theory, we quantified gastrointestinal hormones serum levels in a combine ethanol intoxication and burn injury mouse model. Thus, mice received a daily dose of ethanol for 3 days, rested 4 days, and were given ethanol 3 additional days. Mice underwent 15% TBSA scald burn 30 minutes after their last ethanol dose. Serum samples were collected 24 hours after burn injury. Nonintoxicated burned mice exhibited an increase in glucose, insulin, ghrelin, plasminogen activator inhibitor-1, leptin, and resistin by 1.4-, 3-, 13.5-, 6.2-, 9.4-, and 2.4-fold, respectively, compared to sham vehicle mice (P < .05). Burn injury also reduced serum gastric inhibitory polypeptide (GIP) by 32% compared to sham-injured, vehicle-treated mice. Leptin, resistin, glucagon-like peptide-1, as well as insulin, were not different from sham groups when intoxication preceded burn injury. Nevertheless, in burned mice treated with ethanol, gastric inhibitory polypeptide and glucagon serum levels exhibited a significant fold increase of 3.5 and 4.7, respectively. With these results, we conclude that 24 hours after burn injury, mice developed significant changes in gastrointestinal hormones, along with hyperglycemia. Moreover, the combined insult of burn and ethanol intoxication led to additional hormonal changes that may be attributed to a potential pancreatic dysfunction. Further multiday studies are required to investigate the etiology, behavior, and clinical significance of these hormonal changes.

SUN-LB057 An Interesting Case of Multiple Pancreatic Neuroendocrine Tumour: Normoglycaemic Glucagonoma and Concurrent Gastrinoma

Background: Pancreatic neuro-endocrine tumours (pNETs) are rare tumours, constituting less than 5% of pancreatic tumours. Of these cases, only an estimated 6% present with functional secretion of more than one hormone. Clinical Case: A 72-year-old woman was admitted to the acute frailty ward with symptoms of generalized weakness, fatigue and reduced exercise tolerance with shortness of breath on exertion. She reported unintentional weight loss of 16 kg in the preceding 3 months and widespread migratory rash with epidermal breakdown in the lower legs that was resistant to antibiotic therapy. Initial investigations on admission revealed severe anaemia with a haemoglobin (Hb) of 51 g/L that was refractory to blood transfusion, prompting gastroscopy that showed erosive gastritis. CT/MRI scans revealed a 24 mm solid arterial-enhancing mass lesion in the uncinate process of the pancreas, highly suggestive of a neuroendocrine tumour (NET). Histopathological examination of a skin biopsy showed intraepithelial vacuolisation of the cells in the upper epidermis, neutrophilic infiltration with psoriasiform hyperplasia and confluent parakeratosis; typical features of necrolytic migratory erythema (NME). Fasting serum gut hormone profile prior to omeprazole therapy was consistent with multiple functioning NET with elevated serum glucagon level (>500 pmol/L) and hypergastrinaemia (274 pmol/L). Fasting serum glucose level was 4.5 mmol/L and serum albumin was 24 g/L. Elevated serum fasting serum glucagon and gastrin levels strongly supported diagnosis of neuroendocrine tumour resulting in normoglycaemic glucagonoma syndrome (NME, weight loss without diabetes mellitus) and Zollinger-Ellison syndrome (anaemia and hyperchlorhydria). The rash resolved rapidly less than a week after commencing medical management with octreotide, a somatostatin receptor analogue. She was also commenced on high dose PPI therapy. Somatostatin receptor scintigraphy was performed that confirmed a somatostatin-avid primary tumour in the pancreas without distant metastases. Surveillance will include blood glucose monitoring, interval rescanning with CT abdomen and pelvis with contrast and octreotide scan to assess for metastases. Surgical resection of the tumour will be considered as the patient's performance status improves. Conclusion: We report a rare case of a patient diagnosed with a multiple functioning pNET. The clinician must always consider unconventional rashes as dermatological manifestations of systemic disease. A normal fasting serum glucose level is not a reliable exclusion criterion of glucagonoma syndrome due to functioning insulin secretion from beta pancreatic islet cells. Isolated measurement of fasting serum gastrin level is not appropriate for diagnosis of Zollinger-Ellison syndrome in patients treated with proton pump inhibitors or histamine receptor antagonists. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

SUN-595 Chronic Diarrhea as a Manifestation of Medullary Thyroid Cancer

Background: Tumor secretion of calcitonin (Ct), Ct gene-related peptide, or other substances can cause diarrhea in patients with advanced medullary thyroid cancer (MTC). We report 3 patients with chronic diarrhea due to MTC in whom the diagnosis was delayed. Case 1: A 26-year-old man reported to Gastroenterology (GI) clinic with a 6-month history of diarrhea. An extensive work-up was performed including upper and lower endoscopies that were unrevealing. A diagnosis of chronic diarrhea of unknown etiology was made and patient received symptomatic treatment. Six months later the patient lost about 16 pounds of weight; a chest CT was performed showing a left thyroid mass with cervical lymphadenopathy and skeletal metastases. Biopsy of the thyroid mass confirmed MTC. Serum calcitonin (Ct) level was 52894 ng/L (ref <10). Additional tests (serum VIP, somatostatin, glucagon, pancreatic polypeptide, neurotensin, and gastrin levels) were normal. Two months post thyroidectomy and lymph node dissection, Ct level was 447 ng/L and diarrhea improved. Subsequently serum Ct started rising and imaging studies showed extensive metastases and presently patient is treated with tyrosine kinase inhibitors. Case 2: A 27-year-old woman was referred to GI clinic with a 3-month history of diarrhea. Upper endoscopy and colonoscopy were noncontributory. Detailed laboratory evaluations were normal and a diagnosis of irritable bowel syndrome was made. One month later, thyroid nodules were detected and biopsy of the thyroid nodule revealed MTC. Serum Ct was 2890 ng/L. Patient underwent total thyroidectomy and histology confirmed MTC with metastasis. Two months later, serum Ct was 490 ng/L with improvement in diarrhea and reduced loperamide dosage. Case 3: A 38-year-old man was referred to GI clinic with a 4-month history of diarrhea. Patient underwent a detailed evaluation and was treated with loperamide and tincture of opium with partial improvements. Three months later, a physical examination revealed a 4-cm left thyroid nodule and biopsy suggested MTC. Serum Ct level was 4088 ng/L. Patient underwent total thyroidectomy and lymph node dissection. Histology confirmed MTC. Two months postoperatively, serum Ct level normalized and diarrhea completely resolved. Discussion The link between tumor humoral secretion and diarrhea is well established in patients with MTC as diarrhea is more frequent with metastatic disease and immediately improves after resection of the tumor. The improvement in diarrhea was seen in our patients postoperatively. Diarrhea may result from a secretory process induced by elevated circulating Ct or other substances such as prostaglandin or serotonin. Other proposed mechanisms include decreased absorption in the colon secondary to motor disturbances. In conclusion, MTC should be considered when evaluating chronic diarrhea.

Glucagonoma-Associated Necrolytic Migratory Erythema: The Broad Spectrum of the Clinical and Histopathological Findings and Clues to the Diagnosis

Necrolytic migratory erythema (NEM) is associated with glucagonoma, an endocrine malignancy of the pancreas. It is a rare and a likely underrecognized paraneoplastic dermatitis. A 38-year-old woman presented to our clinic with a 3-year history of reocurring pruritic skin rashes with increasing intensity. The skin lesions presented with active annular borders, central scaling, and postinflammatory hyperpigmentation, but also with erosions, pustules, and crusted lesions. Multiple skin biopsies were taken. The workup of the patient revealed a tumor localized in the head of the pancreas, and glucagon serum levels were elevated. Clues to the diagnosis of NEM were the waxing and waning of serpiginous erythemas with active borders localized on extremities, intertriginous areas, and face. On histopathology, dyskeratosis in all layers of the epidermis were an early feature of NEM, and long-standing lesions typically showed psoriasiform hyperplasia with pallor and necrosis of upper epidermal layers. Clinicians and histopathologists need to be aware of the wide spectrum of skin manifestations in glucagonoma. Early diagnosis of the tumor is crucial for patients.

Defective exocytosis and processing of insulin in a cystic fibrosis mouse model.

Cystic fibrosis-related diabetes (CFRD) is a common complication for patients with cystic fibrosis (CF), a disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). The cause of CFRD is unclear, but a commonly observed reduction in first-phase insulin secretion suggests defects at the beta cell level. Here we aimed to examine beta- and alpha-cell function in the Cftrtm1EUR/F508del mouse model (C57BL/6J), which carries the most common human mutation in CFTR, the F508del mutation. CFTR expression, beta cell mass, insulin granule distribution, hormone secretion and single cell capacitance changes were evaluated using islets (or beta cells) from F508del mice and age-matched wild-type mice aged 7-10 weeks. Granular pH was measured with DND-189 fluorescence. Serum glucose, insulin and glucagon levels were measured in vivo, and glucose tolerance was assessed using IPGTT. We show increased secretion of proinsulin and concomitant reduced secretion of C-peptide in islets from F508del mice compared to WT mice. Exocytosis and number of docked granules was reduced. We confirmed reduced granular pH by CFTR stimulation. We detected decreased pancreatic beta cell area, but unchanged beta cell number. Moreover, the F508del mutation caused failure to suppress glucagon secretion leading to hyperglucagonemia. In conclusion, F508del mice have beta cell defects resulting in 1) reduced number of docked insulin granules and reduced exocytosis, and 2) potential defective proinsulin cleavage and secretion of immature insulin. These observations provide insight into the functional role of CFTR in pancreatic islets and contribute to increased understanding of the pathogenesis of CFRD.

Probiotic Lactobacillus gasseri SBT2055 improves insulin secretion in a diabetic rat model

The probiotic Lactobacillus gasseri SBT2055 (LG2055) has a protective effect against metabolic syndrome in rats and humans. Metabolic syndrome increases the risk of type 2 diabetes mellitus. In this study, Goto-Kakizaki rats were used as a diabetic model and fed diets containing LG2055-fermented or nonfermented skim milk for 4 wk. Indices of diabetes such as blood glucose levels, serum glucagon levels, plasma levels of insulin, C-peptide, and glucagon-like peptide-1, tissue glycogen contents, and pancreatic mRNA levels were measured. The plasma C-peptide levels and pancreatic mRNA levels of insulin genes (Ins1 and Ins2) and Pdx1 (a transcriptional factor of insulin genes) were increased in LG2055 diet-fed rats. The increase in insulin secretion corresponded to an improvement in serum and pancreatic inflammatory status, associated with decreases in serum levels of serum amyloid P and pancreatic levels of granulocyte colony-stimulating factor. Insulin resistance in Goto-Kakizaki rats was ameliorated by increased glycogen storage in the liver and quadriceps femoris muscles and decreased serum free fatty acid levels. This improvement may be related to the increased cecal production of short-chain fatty acids. In conclusion, dietary LG2055 improved insulin secretion in diabetic rats by improving the inflammatory status in the pancreas and serum.

Paeoniflorin Ameliorates Fructose-Induced Insulin Resistance and Hepatic Steatosis by Activating LKB1/AMPK and AKT Pathways.

The present study aimed to evaluate the effects of paeoniflorin on insulin resistance and hepatic steatosis induced by fructose. Male Sprague-Dawley rats were fed 20% fructose drink for eight weeks. The insulin sensitivity, serum lipid profiles, and hepatic lipids contents were measured. The results showed that paeoniflorin significantly decreased serum insulin and glucagon levels, improved insulin sensitivity and serum lipids profiles, and alleviated hepatic steatosis in fructose-fed rats. Moreover, paeoniflorin enhanced the phosphorylation level of AMP-activated protein kinase (AMPK) and protein kinase B (PKB/AKT) and inhibited the phosphorylation of acetyl coenzyme A carboxylase (ACC)1 in liver. Paeoniflorin also increased the hepatic carnitine palmitoyltransferase (CPT)-1 mRNA and protein expression and decreased the mRNA expression of sterol regulatory element-binding protein (SREBP)1c, stearyl coenzyme A decarboxylase (SCD)-1 and fatty acid synthetase (FAS). Furthermore, we found that paeoniflorin significantly increased the heptatic protein expression of tumor suppressor serine/threonine kinase (LKB)1 but not Ca2+/CaM-dependent protein kinase kinase (CaMKK)β. These results suggest that the protective effects of paeoniflorin might be involved in the activation of LKB1/AMPK and insulin signaling, which resulted in the inhibition of lipogenesis, as well as the activation of β-oxidation and glycogenesis, thus ameliorated the insulin resistance and hepatic steatosis. The present study may provide evidence for the beneficial effects of paeoniflorin in the treatment of insulin resistance and non-alcoholic fatty liver.

Acute Caloric Restriction Leads to Loss of Hypoglycemic Counter-Regulation in Mice following Short-Term Refeeding

Background: Hypoglycemia-associated autonomic failure (HAAF) is a maladaptive failure in glucose counter-regulation known to be caused by recurrent exposure to insulin-induced hypoglycemia. Fasting or caloric restriction is the only natural physiological process which induces prolonged moderate-to-severe hypoglycemia similar to the antecedent of HAAF. In this study we tested the hypothesis that exposure to fasting-induced hypoglycemia can cause HAAF-like symptoms in mice. Methods: Two groups of mice were used, an ad libitum (ad lib) fed group (n=6) and a caloric restriction (CR) group (n=6). CR mice were placed on 60% caloric restriction for 6 consecutive days. Ad lib mice were housed in an identical manner but fed ad libitum during this same period. Following 6 days of restriction, CR mice were given ad lib access to food for 16 h. After the 16 h period of refeeding, both CR and ad lib mice began a 6 h fast which was immediately followed by a hypoglycemic insulin tolerance test (ITT). ITTs consisted of a variable dose of insulin (1.4-1.75 U/kg, IP) which produced similar levels of hypoglycemia in each group (∼45 mg/dL). Results: As expected, mice exposed to 6 days of 60% CR lost ≈30% of their initial body weight, and experienced a gradual fall in blood glucose to an average minimum of 67.9 mg/dL. CR mice displayed a significantly reduced fasting glucose level relative to ad lib mice (102.7 and 171.0 mg/dL respectively, p = 0.0002) as well as reduced serum glucagon levels in response to the ITT (6.0 and 30.4 pg/mL respectively, p = 0.0182). Conclusions: Our results demonstrate that exposure to fasting-induced hypoglycemia produces HAAF-like symptoms in mice following refeeding. These results suggest that HAAF may be a result of an adaptive response to fasting which is inappropriately elicited during exposure to insulin-induced hypoglycemia. Further characterization of the effects of CR on the induction of deficits in glucose counterregulation warrants further investigation. Disclosure D. McDougal: None.

Associations of serum glucagon levels with glycemic variability in type 1 diabetes with different disease durations.

Glucagon has been recognized as a pivotal factor implicated in the pathophysiology ofdiabetes. The purpose of this study is to investigate the dynamic secretion levels of serum glucagon (GLA) in patients with type 1 diabetes mellitus (T1DM) with different courses of disease, and to analyze its correlation with blood glucose fluctuation. This observational study included 55 T1DM patients and divided into 3 groups according to the courses of disease. Group 1(the disease duration <1 year), Group 2(1≤the disease durations≤5), 3(the disease durations >5 years). All patients underwent a 100g standard steamed buns meal test,measuring the levels of serum glucose, glucagon, insulin, C-peptide in different points of time, and 48 of the total patients used continuous glucose monitoring system (CGMS) to monitor blood glucose. The fasting glucagon level in Group 1 was significantly higher than it in Group 2. Furthermore, the GLA1h, the GLA3h and the AUCGLA0-3h in Group 1 were greatly larger than those in Group 3. Referring to glycemic variability, the LBGI, AUC of hypoglycemia, the percentage of hypoglycemia time andthe times of nocturnal hypoglycemia in Group 1 were significantly lower than those in Group 3. Moreover,the fasting glucagon level was the independent factors to SD and MAGE. The AUCGLA0-3h were negatively correlated with MODD, LBGI, GRADE-hypo and AUC of nocturnal hypoglycemia. It is concluded that glucagon secretory function impairs with duration of type 1 diabetes extended and correlates to glycemic fluctuation, especially hypoglycemia.

Long-lasting Glucagon-like Peptide 1 Analogue Exendin-4 Ameliorates the Secretory and Synthetic Function of Islets Isolated From Severely Scalded Rats.

The aim of this article was to observe the intracellular insulin content of islets isolated from severely scalded and Exendin-4-treated rats and to evaluate the stimulation of insulin mRNA synthesis and secretion by β cells at different glucose concentrations and during different periods of time. A 50% TBSA full-thickness scalded rat model was used. Rats were treated with Exendin-4, followed by islet isolation and functional measurements. Serum was collected for detection of serum insulin, glucose, and glucagon levels. Intracellular insulin content was determined by transmission electron microscopy. Isolated islets were incubated with different glucose concentrations for 1 or 24 hours to assess the effect of scalding with or without Exendin-4 treatment on functional parameters. Insulin secretion was analyzed by enzyme-linked immunosorbent assay. Intracellular insulin and proinsulin content were analyzed by immunoprecipitation. Islet preproinsulin mRNA expression was examined by real-time polymerase chain reaction. Transmission electron microscopy analyses showed that severe thermal injury significantly reduced the number of insulin granules per micrometer2. Insulin secretion and intracellular insulin and proinsulin levels were markedly reduced in islets stimulated with different glucose concentrations; chronic high-glucose-stimulated islet preproinsulin mRNA expression was also impaired. Exendin-4 treatment after thermal trauma improved the number of intracellular insulin granules. Exendin-4 improved both insulin secretion and intracellular insulin reserves under different glucose stimulation conditions. Islet insulin mRNA expression was also restored by Exendin-4 treatment. Exendin-4 can restore the islet β cell insulin reserve following severe scald injury and may also improve insulin secretion, insulin reserve, and mRNA expression in islet β cells.

Antidiabetic and Antiobesity Effects of Artemether in db/db Mice.

This study is designed to investigate the effect of artemether on type 2 diabetic db/db mice. The experiments consisted of three groups: normal control (NC, db/+, 1% methylcellulose, intragastric administration), diabetic control (DM, db/db, 1% methylcellulose, intragastric administration), and artemether treated (artemether, db/db, 200 mg/kg of artemether, intragastric administration). The treatment lasted for two weeks. The food intake, body weight, and fasting blood glucose of mice were measured every three days. At the start and end of the experiment, the intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (IPITT) were performed. We determined the serum insulin and glucagon levels by ELISA kits and calculated insulin resistance index (HOME-IR). HE staining was used to observe the morphologies of pancreas and liver in mice. The damage of pancreatic beta cells was evaluated by TUNEL staining and immunofluorescence. We found the following: (1) compared with the DM group, the food intake and weight increase rate of artemether group significantly reduced (P < 0.05); (2) compared with pretreatment, artemether significantly reduced the fasting blood glucose levels, and the areas under the curves (AUCs) of IPGTT were decreased significantly, increasing the tolerance to glucose of db/db mice. (P < 0.05); (3) artemether improved hyperinsulinemia and decreased the AUCs of IPITT and HOME-IR, increasing the insulin sensitivity of db/db mice. (4) Artemether significantly ameliorated islet vacuolar degeneration and hepatic steatosis in db/db mice. (5) Artemether reduced the apoptosis of pancreatic beta cells and increased insulin secretion in db/db mice compared with DM group (P < 0.05). Our results indicated that artemether significantly improved glucose homeostasis and insulin resistance and had the potential activity to prevent obesity, reduced the severity of fatty liver, and protected pancreatic beta cells, promising to treat type 2 diabetes.

A Case Series of Molecular Imaging of Glucagonoma After Initial Therapy—68Ga-DOTATATE PET/CT Reveals Similar Results as in Neuroendocrine Tumors of Other Origin in Follow-up and Re-evaluation

Glucagonoma is an extremely rare, glucagon-secreting neuroendocrine tumor of the pancreas. Only sparse data are available about the characteristics of this tumor in somatostatin receptor imaging and only for the situation of initial diagnosis. We present a series of 3 glucagonoma patients who underwent at least 1 Ga-DOTATATE PET/CT scan. All patients were diagnosed by either histology and/or elevated serum levels of glucagon. The presented cases suggest that somatostatin receptor-based imaging can probably be used for re-evaluation of disease status in patients with glucagonoma in a similar way as it is already established for neuroendocrine tumors of other origin.

Islet α-cell Inflammation Induced By NF-κB inducing kinase (NIK) Leads to Hypoglycemia, Pancreatitis, Growth Retardation, and Postnatal Death in Mice.

Islet α-cell dysfunction has been shown to contribute to type 2 diabetes; however, whether islet α-cell inflammation is involved in the occurrence of pancreatitis is largely unknown. The aims of this study were to investigate how NF-κB inducing kinase (NIK) regulates pancreatic α-cell function, both in vitro and in vivo, and to assess how islet α-cell inflammation induced by NIK affects the development of pancreatitis.Methods: We utilized adenovirus-mediated NIK overexpression, ELISA, qPCR, RNA-seq, and Western blot analyses to study the role of NIK in islet α cells in vitro. Islet α-cell-specific NIK overexpressing (α-NIK-OE) mice were generated, and pancreatic α/β-cell function and the occurrence of pancreatitis in these mice were assessed via ELISA, qPCR, and immunohistochemical analyses.Results: The LTβR/noncanonical NF-κB signaling pathway is present in islet α cells. Overexpression of NIK in αTC1-6 cells induces inflammation and cell death, contributing to a decrease in the expression and secretion of glucagon. Additionally, α-cell specific overexpression of NIK (α-NIK-OE) results in α-cell death, lower serum glucagon levels, and hypoglycemia in mice. Strikingly, α-NIK-OE mice also display a reduced β-cell mass, growth retardation, pancreatitis, and postnatal death.Conclusions: Islet α-cell specific overexpression of NIK results in islet α-cell dysfunction and causes islet β-cell death and pancreatitis, which are most likely due to paracrine secretion of cytokines and chemokines from islet α cells, thus leading to hypoglycemia, growth retardation, and postnatal death in mice.

Once-weekly administration of dulaglutide, a glucagon-like peptide-1 receptor agonist, as monotherapy and combination therapy: review of the AWARD studies

For the purpose of exploring the development, pharmacology and clinical trial program related to dulaglutide, we conducted a nonsystematic review of dulaglutide, focusing on the AWARD (Assessment of Weekly Administration of LY2189265 [dulaglutide] in Diabetes Assessment) program of randomized, phase 3 studies. Dulaglutide is a glucagon-like peptide 1 (GLP-1) receptor agonist that causes a variety of antidiabetogenic actions by acting on the incretin system. Steady-state plasma concentrations of dulaglutide are achieved between 2 and 4 weeks following a once-weekly administration. The AWARD 16 studies were conducted in patients with different treatment needs, ranging from patients with mild diabetes who can be treated with diet management and exercise to patients for whom target glycemic control cannot be achieved with conventional insulin treatment. Changes in HbA1c from baseline to the primary endpoint assessment (primary efficacy outcome) with dulaglutide were generally dose-dependent and significantly greater than those of active comparators and placebos (AWARD 15) or non-inferior to the comparators (AWARD 6). The results of secondary outcome measures demonstrated that glycemic control attained with dulaglutide was sustained for long-term and that a greater proportion of patients treated with dulaglutide achieved a target HbA1c level of 7.0% compared with placebo and/or active comparators. Reduction in fasting serum glucose, glucagon levels and body weight after dulaglutide treatment were noted in most AWARD studies. Although treatment-emergent adverse events were common with dulaglutide, the incidence was similar to that of active comparators in most AWARD studies, and serious adverse events were generally infrequent, except in patients with more severe disease or with prolonged therapy. Hypoglycemic and immunogenic events were also infrequent.&#x0D; In patients with type 2 diabetes, dulaglutide improves glycemic control and leads to clinically useful reduction in body weight in a range of treatment settings.

Tributyltin in male mice disrupts glucose homeostasis as well as recovery after exposure: mechanism analysis

Organotin compounds such as tributyltin (TBT) and triphenyltin can induce diabetes and insulin resistance. However, the development of diabetes caused by organotins and its underlying mechanisms remain unclear. In the present study, male KM mice were orally administered with TBT (0.5, 5, and 50μg/kg) once every 3days for 45days. Their body weights increased and reached a significant difference compared to the control, and the fasting blood glucose levels were significantly elevated. The fasting levels of serum insulin and adiponectin increased, while glucagon levels decreased in the animals treated with TBT. The expression of the insulin receptor (IR) signaling cascade, including IR, IR substrate, phosphatidylinositol 3-kinase, Akt, and glucose transporter 4, was inhibited both in the skeletal muscle and the liver, which might be a main reason for the hyperglycemia and hyperinsulinemia. After removing the TBT stress for 60days, the animals which had received exposure to TBT could recover normoglycemia, accompanied with a recovery of the suppressed IR signal pathway and fasting insulin levels. However, the fasting levels of serum adiponectin and glucagon were lower than that of the control mice, which would remain a potential risk inducing the disruption of glucose homeostasis.

Evaluation of anti-fatigue and immunomodulating effects of quercetin in strenuous exercise mice

The purpose of the present study was to investigate the anti-fatigue and immunomodulating effects of quercetin in strenuous exercise mice. Mice were given orally either corn oil or quercetin (20, 40 and 60 mg/kg body weight suspended in corn oil) by gavage once a day for 28 day. All mice were sacrificed after rotarod test and the major biochemical parameters were analyzed in serum and liver. The results indicated that quercetin possessed anti-fatigue effects by prolonging retention times, decreasing levels of blood lactate and serum urea nitrogen, and increasing levels of blood glucose, tissue glycogen and serum glucagon. Furthermore, quercetin could improve the immune function of fatigue mice by decreasing tumor necrosis factor-α levels, and elevated interleukin-10 levels. Quercetin possessed anti-fatigue effects may be related to its immunomodulating effects.