Active Glucagon-like Peptide-1 Research Articles

Gut microbiota is correlated with gastrointestinal adverse events of metformin in patients with type 2 diabetes.

Gastrointestinal discomfort is the most common adverse event in metformin treatment for type 2 diabetes. The mechanism of action of metformin is associated with gut microbiota. However, the gut microbial community structure related to metformin-induced gastrointestinal adverse events remains unclear. This study aimed to investigate it. 50 patients with newly diagnosed diabetes were treated with metformin 1500mg/d for 12 weeks. The patients were divided into two groups according to whether gastrointestinal adverse events occurred (group B) or did not occur (group A) after treatment. The fecal bacterial communities and short-chain fatty acids (SCFAs) were sequenced and compared. 70 diabetes mice were randomly divided into 8 groups and treated with metformin (Met), clindamycin (Clin) and/or SCFA, which were the Met+/Clin+, Met+/Clin-, Met-/Clin+, Met-/Clin-, Met+/SCFA+, Met+/SCFA-, Met-/SCFA+ and Met-/SCFA- group. After 4 weeks of metformin treatment, blood glucose, food intake, fecal SCFAs, gut microbiota and gut hormones were measured. Metformin increased the abundance of Phascolarctobacterium, Intestinimonas and Clostridium III. Functional prediction analysis showed that the propanoate metabolism pathway was significantly up-regulated. The concentrations of acetic acid and propanoic acid in feces were significantly increased. The abundance of Clostridium sensu stricto, Streptococcus and Akkermansia induced by metformin in group B was higher than that in group A. The propanoate metabolism pathway and propanoic acid in feces were significantly up-regulated in group B. In the animal experiments, the food intake decreased and glucose control increased in metformin groups compared with those in the control groups. The total GLP-1 level in the Met+/Clin- group was significantly higher than that in the Met-/Clin- group, while there was no statistical difference between the Met-/Clin- and Met+/Clin+ group. The total GLP-1 level in the Met-/SCFA+ group was significantly higher than that in the Met-/SCFA-group, while the levels of total GLP-1 and active GLP-1 in the Met+/SCFA- group and the Met+/SCFA+ group were significantly higher than those in the Met-/SCFA-group. Our data suggest that metformin promotes the secretion of intestinal hormones such as GLP-1 by increasing the abundance of SCFA-producing bacteria, which not only plays an anti-diabetic role, but also may causes gastrointestinal adverse events.

Antidiabetic Actions of Ethanol Extract of Camellia sinensis Leaf Ameliorates Insulin Secretion, Inhibits the DPP-IV Enzyme, Improves Glucose Tolerance, and Increases Active GLP-1 (7-36) Levels in High-Fat-Diet-Fed Rats.

Camellia sinensis (green tea) is used in traditional medicine to treat a wide range of ailments. In the present study, the insulin-releasing and glucose-lowering effects of the ethanol extract of Camellia sinensis (EECS), along with molecular mechanism/s of action, were investigated in vitro and in vivo. The insulin secretion was measured using clonal pancreatic BRIN BD11 β cells, and mouse islets. In vitro models examined the additional glucose-lowering properties of EECS, and 3T3L1 adipocytes were used to assess glucose uptake and insulin action. Non-toxic doses of EECS increased insulin secretion in a concentration-dependent manner, and this regulatory effect was similar to that of glucagon-like peptide 1 (GLP-1). The insulin release was further enhanced when combined with isobutylmethylxanthine (IBMX), tolbutamide or 30 mM KCl, but was decreased in the presence of verapamil, diazoxide and Ca2+ chelation. EECS also depolarized the β-cell membrane and elevated intracellular Ca2+, suggesting the involvement of a KATP-dependent pathway. Furthermore, EECS increased glucose uptake and insulin action in 3T3-L1 cells and inhibited dipeptidyl peptidase IV (DPP-IV) enzyme activity, starch digestion and protein glycation in vitro. Oral administration of EECS improved glucose tolerance and plasma insulin as well as inhibited plasma DPP-IV and increased active GLP-1 (7-36) levels in high-fat-diet-fed rats. Flavonoids and other phytochemicals present in EECS could be responsible for these effects. Further research on the mechanism of action of EECS compounds could lead to the development of cost-effective treatments for type 2 diabetes.

Activation of arcuate nucleus glucagon-like peptide-1 receptor-expressing neurons suppresses food intake

BackgroundCentral nervous system (CNS) control of metabolism plays a pivotal role in maintaining energy balance. In the brain, Glucagon-like peptide 1 (GLP-1), encoded by the proglucagon ‘Gcg’ gene, produced in a distinct population of neurons in the nucleus tractus solitarius (NTS), has been shown to regulate feeding behavior leading to the suppression of appetite. However, neuronal networks that mediate endogenous GLP-1 action in the CNS on feeding and energy balance are not well understood.ResultsWe analyzed the distribution of GLP-1R-expressing neurons and axonal projections of NTS GLP-1-producing neurons in the mouse brain. GLP-1R neurons were found to be broadly distributed in the brain and specific forebrain regions, particularly the hypothalamus, including the arcuate nucleus of the hypothalamus (ARC), a brain region known to regulate energy homeostasis and feeding behavior, that receives dense NTSGcg neuronal projections. The impact of GLP-1 signaling in the ARC GLP-1R-expressing neurons and the impact of activation of ARC GLP-1R on food intake was examined. Application of GLP-1R specific agonist Exendin-4 (Exn-4) enhanced a proportion of the ARC GLP-1R-expressing neurons and pro-opiomelanocortin (POMC) neuronal action potential firing rates. Chemogenetic activation of the ARC GLP-1R neurons by using Cre-dependent hM3Dq AAV in the GLP-1R-ires-Cre mice, established that acute activation of the ARC GLP-1R neurons significantly suppressed food intake but did not have a strong impact on glucose homeostasis.ConclusionsThese results highlight the importance of central GLP-1 signaling in the ARC that express GLP-1R that upon activation, regulate feeding behavior.

Polyphenol-Rich Leaf of Annona squamosa Stimulates Insulin Release from BRIN-BD11 Cells and Isolated Mouse Islets, Reduces (CH2O)n Digestion and Absorption, and Improves Glucose Tolerance and GLP-1 (7-36) Levels in High-Fat-Fed Rats.

Annona squamosa, commonly known as custard apple, is traditionally used for the treatment of various diseases including diabetes, cardiovascular disease (CVD), and gastritis. This study was undertaken to investigate the effects of an ethanolic (80% v/v) extract of A. squamosa (EEAS) leaves in vitro on insulin secretion from clonal pancreatic BRIN BD11 β-cells and mouse islets, including mechanistic studies on the effect of EEAS on membrane potential and intracellular calcium ion concentration. Additional in vitro glucose-lowering actions were assessed. For in vivo studies, high-fat-fed (HFF) obese/normal rats were selected. EEAS increased insulin secretion in vitro in a dose-dependent manner. This effect was linked to β-cell membrane depolarisation and cytoplasmic Ca2+ influx. In the presence of isobutyl methylxanthine (IBMX), tolbutamide, or KCl, the insulin-releasing effect of EEAS was increased, suggesting its effect was also mediated via a KATP-independent pathways. EEAS inhibited insulin glycation, glucose absorption, and DPP-IV enzyme activity in vitro and enhanced glucose uptake and insulin action in 3T3L1 cells. In vivo, gut motility, food intake, glucose tolerance, plasma insulin, and active GLP-1 (7-36) levels were improved, whereas plasma DPP-IV levels were reduced in HFF rats. EEAS attenuated the absorption of sucrose and glucose as well as decreased serum glucose levels after sucrose loading and in situ intestinal perfusion in non-diabetic rats. Rutin, proanthocyanidin, and squafosacin G were putatively identified as the anti-hyperglycaemic phytomolecules in EEAS using HPLC followed by LC-MS analysis. This study illustrates the potential of A. squamosa and its phytoconstituents as a source of potential antidiabetic agents.

Anti-Inflammatory Effects of GLP-1R Activation in the Retina.

Glucagon-like peptide-1 (GLP-1) is an incretin hormone, mainly produced by enteroendocrine L cells, which participates in the regulation of glucose homeostasis, and in reduction in body weight by promoting satiety. Actions of GLP-1 are mediated by activation of its receptor GLP-1R, which is widely expressed in several tissues including the retina. The effects of GLP-1R activation are useful in the management of type 2 diabetes mellitus (T2DM). In addition, the activation of GLP-1R has anti-inflammatory effects in several organs, suggesting that it may be also useful in the treatment of inflammatory diseases. Inflammation is a common element in the pathogenesis of several ocular diseases, and the protective effects of treatment with GLP-1 emerged also in retinal diseases. In this review we highlight the anti-inflammatory effects of GLP-1R activation in the retina. Firstly, we summarized the pathogenic role of inflammation in ocular diseases. Then, we described the pleiotropic effects of GLP-1R activation on the cellular components of the retina which are mainly involved in the pathogenesis of inflammatory retinal diseases: the retinal ganglion cells, retinal pigment epithelial cells and endothelial cells.

Examining The Potential Involvement Of Ovarian Hormones On Appetite In Females Across The Menstrual Cycle

Appetite regulation has exclusively been examined during the follicular phase (FP) of themenstrual cycle, and it remains unclear whether the greater levels of ovarian hormones estradiol (E2) and progesterone (P4) in the luteal phase (LP) affect this process. PURPOSE: To utilize vigorous-intensity continuous training (VICT) as a method to increase plasma concentrations of E2 and P4 and examine their associations with post-exercise alterations in acylated ghrelin, peptide tyrosine-tyrosine3-36 (PYY3-36), active glucagon like peptide-1 (GLP-1), subjective appetite perceptions, and energy intake across the menstrual cycle. METHODS: Eight women (age: 22 ± 3 y, BMI: 23.6 ± 3.9 kg·m-2, V̇O2max: 37.9 ± 4.5 mL·kg-1·min-1) completed 30 min of VICT (80% V̇O2max) in both the FP and LP. Ovarian (E2, P4) and appetite hormones (acylated ghrelin, PYY3-36, active GLP-1) as well as appetite perceptions were measured pre-, 0-, 30-, and 90-min post-exercise while energy intake was recorded for a 2-day period beginning the day of the experimental session. Two-way repeated measures analysis of variance were conducted to determine differences in hormones, energy intake, and appetite perceptions. RESULTS: E2 increased immediately post-exercise in both the FP and LP (17% or 13.4 pgmL-1; P = 0.041, ƒ = 0.71) with an increase in P4 trending towards significance in the LP (17% or 2.1 ngmL-1 P = 0.078, ƒ = 0.23). Acylated ghrelin was lower in the FP compared to the LP (-50% or -68.6 pgmL-1; P = 0.029, ƒ = 1.03) immediately post-exercise but greater at 90 min post-exercise compared to immediately post-exercise (78% or 106.3 pgmL-1, P = 0.036, ƒ = 0.87) and 30 min post-exercise (78% or 106.2 pgmL-1, P = 0.014) in both phases. Active GLP-1 was elevated at 30 min compared to 90 min post-exercise (39% or 5.8 pMmL-1; P = 0.016, ƒ = 0.73) with no differences between phases (P = 0.238, ƒ = 0.44). There were no observable effects of exercise or menstrual cycle phase on PYY3-36 (P = 0.305, ƒ = 0.41), overall appetite (P = 0.616, ƒ = 0.25), or free-living energy intake (P = 0.244, ƒ = 0.44). CONCLUSION: The post-exercise suppression of acylated ghrelin may be blunted in the presence of elevated ovarian hormones in the LP, though this effect may not play a role in the anorectic effect of exercise and the differences seen in energy intake across the menstrual cycle.

Insulin Secretory Actions of Ethanol Extract of Eucalyptus citriodora Leaf, including Plasma DPP-IV and GLP-1 Levels in High-Fat-Fed Rats, as Well as Characterization of Biologically Effective Phytoconstituents.

Due to the numerous adverse effects of synthetic drugs, researchers are currently studying traditional medicinal plants to find alternatives for diabetes treatment. Eucalyptus citriodora is known to be used as a remedy for various illnesses, including diabetes. This study aimed to explore the effects of ethanol extract of Eucalyptus citriodora (EEEC) on in vitro and in vivo systems, including the mechanism/s of action. The methodology used involved the measurement of insulin secretion from clonal pancreatic β-cells, BRIN BD11, and mouse islets. Other in vitro systems further examined EEEC’s glucose-lowering properties. Obese rats fed a high-fat-fed diet (HFF) were selected for in vivo evaluation, and phytoconstituents were detected via RP-HPLC followed by LC-MS. EEEC induced insulin secretion in a concentration-dependent manner with modulatory effects, similar to 1 µM glucagon-like peptide 1 (GLP-1), which were partly declined in the presence of Ca2+-channel blocker (Verapamil), KATP-channel opener (Diazoxide), and Ca2+ chelation. The insulin secretory effects of EEEC were augmented by isobutyl methylxanthine (IBMX), which persisted in the context of tolbutamide or a depolarizing concentration of KCl. EEEC enhanced insulin action in 3T3-L1 cells and reduced glucose absorption, and protein glycation in vitro. In HFF rats, it improved glucose tolerance and plasma insulin, attenuated plasma DPP-IV, and induced active GLP-1 (7-36) levels in circulation. Rhodomyrtosone B, Quercetin-3-O-β-D-glucopyranoside, rhodomyrtosone E, and quercitroside were identified as possible phytoconstituents that may be responsible for EEEC effects. Thus, these findings revealed that E. citriodora could be used as an adjunct nutritional supplement to manage type 2 diabetes.

Identification of key genes and pathways revealing the central regulatory mechanism of brain-derived glucagon-like peptide-1 on obesity using bioinformatics analysis.

ObjectiveCentral glucagon-like peptide-1 (GLP-1) is a target in treating obesity due to its effect on suppressing appetite, but the possible downstream key genes that GLP-1 regulated have not been studied in depth. This study intends to screen out the downstream feeding regulation genes of central GLP-1 neurons through bioinformatics analysis and verify them by chemical genetics, which may provide insights for future research.Materials and methodsGSE135862 genetic expression profiles were extracted from the Gene Expression Omnibus (GEO) database. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were carried out. STRING database and Cytoscape software were used to map the protein-protein interaction (PPI) network of the differentially expressed genes (DEGs). After bioinformatics analysis, we applied chemogenetic methods to modulate the activities of GLP-1 neurons in the nucleus tractus solitarius (NTS) and observed the alterations of screened differential genes and their protein expressions in the hypothalamus under different excitatory conditions of GLP-1 neurons.ResultsA total of 49 DEGs were discovered, including 38 downregulated genes and 11 upregulated genes. The two genes with the highest expression scores were biglycan (Bgn) and mitogen-activated protein kinase activated protein kinase 3 (Mapkapk3). The results of GO analysis showed that there were 10 molecular functions of differential genes. Differential genes were mainly localized in seven regions around the cells, and enriched in 10 biology processes. The results of the KEGG signaling pathway enrichment analysis showed that differential genes played an important role in seven pathways. The top 15 genes selected according to the Cytoscape software included Bgn and Mapkapk3. Chemogenetic activation of GLP-1 in NTS induced a decrease in food intake and body mass, while chemogenetic inhibition induced the opposite effect. The gene and protein expression of GLP-1 were upregulated in NTS when activated by chemogenetics. In addition, the expression of Bgn was upregulated and that of Mapkapk3 was downregulated in the hypothalamus.ConclusionOur data showed that GLP-1 could modulate the protein expression of Bgn and Mapkapk3. Our findings elucidated the regulatory network in GLP-1 to obesity and might provide a novel diagnostic and therapeutic target for obesity.

Metagenomic analysis reveals crosstalk between gut microbiota and glucose-lowering drugs targeting the gastrointestinal tract in Chinese patients with type 2 diabetes: a 6 month, two-arm randomised trial

Aims/hypothesisThe use of oral glucose-lowering drugs, particularly those designed to target the gut ecosystem, is often observed in association with altered gut microbial composition or functional capacity in individuals with type 2 diabetes. The gut microbiota, in turn, plays crucial roles in the modulation of drug efficacy. We aimed to assess the impacts of acarbose and vildagliptin on human gut microbiota and the relationships between pre-treatment gut microbiota and therapeutic responses.MethodsThis was a randomised, open-labelled, two-arm trial in treatment-naive type 2 diabetes patients conducted in Beijing between December 2016 and December 2017. One hundred participants with overweight/obesity and newly diagnosed type 2 diabetes were recruited from the Pinggu Hospital and randomly assigned to the acarbose (n=50) or vildagliptin (n=50) group using sealed envelopes. The treatment period was 6 months. Blood, faecal samples and visceral fat data from computed tomography images were collected before and after treatments to measure therapeutic outcomes and gut microbiota. Metagenomic datasets from a previous type 2 diabetes cohort receiving acarbose or glipizide for 3 months were downloaded and processed. Statistical analyses were applied to identify the treatment-related changes in clinical variables, gut microbiota and associations.ResultsNinety-two participants were analysed. After 6 months of acarbose (n=44) or vildagliptin (n=48) monotherapy, both groups achieved significant reductions in HbA1c (from 60 to 46 mmol/mol [from 7.65% to 6.40%] in the acarbose group and from 59 to 44 mmol/mol [from 7.55% to 6.20%] in the vildagliptin group) and visceral fat areas (all adjusted p values for pre–post comparisons <0.05). Both arms showed drug-specific and shared changes in relative abundances of multiple gut microbial species and pathways, especially the common reductions in Bacteroidetes species. Three months and 6 months of acarbose-induced changes in microbial composition were highly similar in type 2 diabetes patients from the two independent studies. Vildagliptin treatment significantly enhanced fasting active glucagon-like peptide-1 (GLP-1) levels. Baseline gut microbiota, rather than baseline GLP-1 levels, were strongly associated with GLP-1 response to vildagliptin, and to a lesser extent with GLP-1 response to acarbose.Conclusions/interpretationThis study reveals common microbial responses in type 2 diabetes patients treated with two glucose-lowering drugs targeting the gut differently and acceptable performance of baseline gut microbiota in classifying individuals with different GLP-1 responses to vildagliptin. Our findings highlight bidirectional interactions between gut microbiota and glucose-lowering drugs.Trial registrationClinicalTrials.gov NCT02999841FundingNational Key Research and Development Project: 2016YFC1304901.Graphical abstract

Alpha-cell paracrine signaling in the regulation of beta-cell insulin secretion.

As an incretin hormone, glucagon-like peptide 1 (GLP-1) lowers blood glucose levels by enhancing glucose-stimulated insulin secretion from pancreatic beta-cells. Therapies targeting the GLP-1 receptor (GLP-1R) use the classical incretin model as a physiological framework in which GLP-1 secreted from enteroendocrine L-cells acts on the beta-cell GLP-1R. However, this model has come into question, as evidence demonstrating local, intra-islet GLP-1 production has advanced the competing hypothesis that the incretin activity of GLP-1 may reflect paracrine signaling of GLP-1 from alpha-cells on GLP-1Rs on beta-cells. Additionally, recent studies suggest that alpha-cell-derived glucagon can serve as an additional, albeit less potent, ligand for the beta-cell GLP-1R, thereby expanding the role of alpha-cells beyond that of a counterregulatory cell type. Efforts to understand the role of the alpha-cell in the regulation of islet function have revealed both transcriptional and functional heterogeneity within the alpha-cell population. Further analysis of this heterogeneity suggests that functionally distinct alpha-cell subpopulations display alterations in islet hormone profile. Thus, the role of the alpha-cell in glucose homeostasis has evolved in recent years, such that alpha-cell to beta-cell communication now presents a critical axis regulating the functional capacity of beta-cells. Herein, we describe and integrate recent advances in our understanding of the impact of alpha-cell paracrine signaling on insulin secretory dynamics and how this intra-islet crosstalk more broadly contributes to whole-body glucose regulation in health and under metabolic stress. Moreover, we explore how these conceptual changes in our understanding of intra-islet GLP-1 biology may impact our understanding of the mechanisms of incretin-based therapeutics.

The glucagon-like peptide-1 system is modulated by acute and chronic alcohol exposure: Findings from human laboratory experiments and a post-mortem brain study.

Growing evidence suggests that the glucagon-like peptide-1 (GLP-1) system modulates alcohol seeking and consumption, and GLP-1 analogues may represent novel pharmacotherapies for alcohol use disorder (AUD). Accordingly, it is important to understand the potential effects of alcohol on the endogenous GLP-1 system. In a series of secondary analyses of previous human laboratory experiments, we first examined the effects of alcohol administration, with different doses and routes of administration, on peripheral active GLP-1 concentrations in heavy-drinking individuals with AUD enrolled in placebo-controlled pharmacological studies (only placebo conditions were analysed here). Alcohol administration resulted in a significant reduction of GLP-1 levels across the four experiments (oral alcohol, variable dose: F3,28 = 6.52, p = 0.002; oral alcohol, fixed dose: F7,75.94 = 5.08, p < 0.001; intravenous alcohol, variable dose: F4,37.03 = 20.72, p < 0.001; intravenous alcohol, fixed dose: F4,13.92 = 10.44, p < 0.001). Next, central expression of the GLP-1 receptor (GLP-1R) in post-mortem brain tissues (amygdala, ventral tegmental area, nucleus accumbens, hippocampus and prefrontal cortex) was compared between individuals with AUD and controls. Fold change of GLP-1R mRNA in the hippocampus was significantly higher in individuals with AUD, compared to controls (F1,21 = 6.80, p = 0.01). A trend-level effect with the same direction was also found in the prefrontal cortex (F1,20 = 3.07, p = 0.09). Exploratory analyses showed that GLP-1R gene expression levels were correlated with behavioural measures of alcohol drinking (hippocampus) and cigarette smoking (hippocampus and prefrontal cortex). Collectively, these data provide novel information on the crosstalk between alcohol and GLP-1 in a clinically relevant sample. Further studies are needed to understand the underlying mechanisms of this link.

Structurally-engineered fatty acid 1024 (SEFA-1024) improves diet-induced obesity, insulin resistance, and fatty liver disease.

Obesity is a global epidemic that drives morbidity and mortality through cardiovascular disease, diabetes, and non-alcoholic fatty liver disease (NAFLD). No definitive therapy has been approved to improve glycemic control and treat NAFLD in obese patients. Here, we investigated a semi-synthetic, long chain, structurally-engineered fatty acid-1024 (SEFA-1024), as a treatment for obesity-induced hyperglycemia, insulin-resistance, and fatty liver disease in rodent models. A single dose of SEFA-1024 was administered to evaluate glucose tolerance and active glucagon-like peptide 1 (GLP-1) in lean rats in the presence and absence of a DPP-4 inhibitor. The effects of SEFA-1024 on weight loss and glycemic control were assessed in genetic (ob/ob) and environmental (high-fat diet) murine models of obesity. Liver histology, serum liver enzymes, liver lipidomics, and hepatic gene expression were also assessed in the high-fat diet murine model. SEFA-1024 reversed obesity-associated insulin resistance and improved glycemic control. SEFA-1024 increased active GLP-1. In a long-term model of diet-induced obesity, SEFA-1024 reversed excessive weight gain, hepatic steatosis, elevated liver enzymes, hepatic lipotoxicity, and promoted fatty acid metabolism. SEFA-1024 is an enterohepatic-targeted, eicosapentaenoic acid derivative that reverses obesity-induced dysregulated glucose metabolism and hepatic lipotoxicity in genetic and dietary rodent models of obesity. The mechanism by which SEFA-1024 works may include increasing aGLP-1, promoting fatty acid oxidation, and inhibiting hepatic triglyceride formation. SEFA-1024 may serve as a potential treatment for obesity-related diabetes and NAFLD.

Association of GLP1R Polymorphisms With the Incretin Response.

Polymorphisms in the gene encoding the glucagon-like peptide-1 receptor (GLP1R) are associated with type 2 diabetes but their effects on incretin levels remain unclear. We evaluated the physiologic and hormonal effects of GLP1R genotypes before and after interventions that influence glucose physiology. Pharmacogenetic study conducted at 3 academic centers in Boston, Massachusetts. A total of 868 antidiabetic drug-naïve participants with type 2 diabetes or at risk for developing diabetes. We analyzed 5 variants within GLP1R (rs761387, rs10305423, rs10305441, rs742762, and rs10305492) and recorded biochemical data during a 5-mg glipizide challenge and a 75-g oral glucose tolerance test (OGTT) following 4 doses of metformin 500 mg over 2 days. We used an additive mixed-effects model to evaluate the association of these variants with glucose, insulin, and incretin levels over multiple timepoints during the OGTT. During the OGTT, the G-risk allele at rs761387 was associated with higher total GLP-1 (2.61 pmol/L; 95% CI, 1.0.72-4.50), active GLP-1 (2.61 pmol/L; 95% CI, 0.04-5.18), and a trend toward higher glucose (3.63; 95% CI, -0.16 to 7.42 mg/dL) per allele but was not associated with insulin. During the glipizide challenge, the G allele was associated with higher insulin levels per allele (2.01 IU/mL; 95% CI, 0.26-3.76). The other variants were not associated with any of the outcomes tested. GLP1R variation is associated with differences in GLP-1 levels following an OGTT load despite no differences in insulin levels, highlighting altered incretin signaling as a potential mechanism by which GLP1R variation affects T2D risk.

A Pilot Study to Assess Glucose, Insulin, and Incretin Responses Following Novel High Resistant Starch Rice Ingestion in Healthy Men.

IntroductionA newly developed resistant starch (RS) rice line with double mutation of starch synthase IIIa and branching enzyme IIb (ss3a/be2b) exhibits a tenfold greater percentage RS value than the wild-type rice line. Currently, the effects of cooked rice with such high RS content on secretion and action of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are unclear. Therefore, we conducted a pilot study to assess postprandial responses of GLP-1 and GIP along with glucose and insulin and also gastric emptying after ingestion of the high-RS cooked rice with ss3a/be2b in healthy subjects.MethodsIn a non-randomized crossover design, five healthy men ingested two test foods, control (low-RS) and high-RS cooked rice, with at least 1-week washout period between testing days. Plasma glucose, serum insulin, plasma total GLP-1, plasma total GIP, and also gastric emptying rate were measured after ingestion of each test food, and the incremental area under the curves (iAUC) was calculated for each biochemical parameter using the values from 0 to 180 min after ingestion.ResultsThe high-RS cooked rice ingestion tended to reduce iAUC-glucose (p = 0.06) and significantly reduced iAUC-insulin (p < 0.01) and iAUC-GLP-1 (p < 0.05) but not iAUC-GIP (p = 0.21) relative to control cooked rice ingestion. In addition, the high-RS cooked rice ingestion did not affect gastric emptying.ConclusionsThe present results indicate that the suppressive effects of the high-RS cooked rice ingestion on postprandial responses of glucose and insulin may be provided through attenuation in GLP-1 secretion along with its low digestibility into glucose. We suggest that the high-RS rice with ss3a/be2b may serve as a better carbohydrate source and also as a novel functional food for dietary interventions to improve postprandial hyperglycemia and hyperinsulinemia without both enhancing GLP-1 secretion and affecting gastric emptying in patients with diabetes.

Glucose-sensing glucagon-like peptide-1 receptor neurons in the dorsomedial hypothalamus regulate glucose metabolism.

Glucagon-like peptide-1 (GLP-1) regulates energy homeostasis via activation of the GLP-1 receptors (GLP-1Rs) in the central nervous system. However, the mechanism by which the central GLP-1 signal controls blood glucose levels, especially in different nutrient states, remains unclear. Here, we defined a population of glucose-sensing GLP-1R neurons in the dorsomedial hypothalamic nucleus (DMH), by which endogenous GLP-1 decreases glucose levels via the cross-talk between the hypothalamus and pancreas. Specifically, we illustrated the sufficiency and necessity of DMHGLP-1R in glucose regulation. The activation of the DMHGLP-1R neurons is mediated by a cAMP-PKA–dependent inhibition of a delayed rectifier potassium current. We also dissected a descending control of DMHGLP-1R –dorsal motor nucleus of the vagus nerve (DMV)–pancreas activity that can regulate glucose levels by increasing insulin release. Thus, our results illustrate how central GLP-1 action in the DMH can induce a nutrient state–dependent reduction in blood glucose level.

Glucagon-like peptide-2 mobilization of intestinal lipid does not require canonical enterocyte chylomicron synthetic machinery

Background & aimsDietary triglycerides (TG) retained in the intestine after a meal can be mobilized many hours later by glucagon-like peptide-2 (GLP-2) in humans and animal models, despite the well-documented absence of expression of the GLP-2 receptor on enterocytes. In this study, we examined the site of GLP-2 action to mobilize intestinal lipids and enhance chylomicron production. MethodsIn mesenteric lymph duct-cannulated rats, we assessed GLP-2-stimulated lymph flow rate, TG concentration, TG output, and apoB48 abundance 5 h after an intraduodenal lipid bolus, in the presence of a validated GLP-2 antagonist or vehicle. Additionally, the same GLP-2-stimulated parameters were examined in the presence or absence of cis-Golgi disruption by Brefeldin A (BFA). ResultsCompared to placebo, GLP-2 administration increased lymph flow by 2.8-fold (P < 0.001), cumulative lymph volume by 2.69-fold (P < 0.001) and total TG output 2-fold (P = 0.015). GLP-2 receptor antagonism markedly diminished GLP-2's ability to stimulate lymph flow, cumulative lymph volume and total TG output, demonstrating the dependence of GLP-2 stimulation of lymph flow and TG output on its receptor activation. In contrast, disruption of the cis-Golgi apparatus with Brefeldin A did not diminish the GLP-2-response of lymph flow i.e., increased lymph flow by 2.7-fold (P = 0.001), lymph volume by 2.9-fold (P = 0.001), and total TG output i.e., increased by 2.5-fold (P = 0.003). ConclusionsGLP-2 mobilizes enteral lipid at a site distal to the Golgi, acting via its receptor. Since GLP-2 receptors are not expressed on enterocytes, GLP-2 likely mobilizes intestinal lipid residing extracellularly, either in the lamina propria or in the lymphatics.

1385-P: Impact of Preanalytical and Analytical Factors on Glucagon and GLP-1 Levels in Humans

Glucagon and glucagon-like peptide-1 (GLP-1) have important roles in the development and treatment of diabetes. Their plasma concentrations are currently being measured in more than 500 clinical studies according to clinicaltrial.gov. As glucagon and total GLP-1 (reflecting the secretion and action of GLP-1 and is analytically independent of DPP-4 activity) circulate in the low picomolar range it has been troublesome to accurately measure their plasma concentrations. Equally important are so-called preanalytical considerations including the use of enzyme inhibitors. The latter may also depend on the analytical approach, for example single-antibody assay versus sandwich ELISA. To provide guidelines for measurement of glucagon and GLP-1 in clinical trials we obtained blood samples using four different blood-containers (with either neprilysin inhibitor: sacubitrilat 25 µg/mL; trasylol 500KIU/mL; P800 tubes; or vehicle) from healthy individuals (male/female; 7/4; mean ± SD; age: 32 ± 12 years, BMI; 26 ± 4 kg/m2) after an overnight fast and following an intravenous amino acid (AA) infusion (14 g/L; 331 mg/min/kg body weight. Plasma concentrations of glucagon increased significantly during the AA-infusion independent of blood containers and assays. The sandwich ELISA showed significant lower levels of glucagon with addition of neprilysin inhibitor whereas both trasylol and P800 tubes resulted in increased levels during the AA-infusion. Glucagon levels measured by the two radioimmunoassays (RIA) did not depend on the containers. Levels of total GLP-1 did not depend on the containers using a sandwich ELISA (Mercodia) but increased by a factor of a 2.5 when plasma from P800 containers was assayed using a C-terminal specific RIA. In summary, levels of glucagon and GLP-1 depend on both preanalytical and analytical factors that should be standardized for future clinical studies. Disclosure S. Kjeldsen: None. N.J. Jensen: None. N. Heinz: None. B. Hartmann: Board Member; Bainan Biotech. J.J. Holst: Advisory Panel; Novo Nordisk. Board Member; Antag Therapeutics, Bainan Biotech. N.J. Wewer Albrechtsen: Research Support; Mercodia AB, Novo Nordisk, Regeneron Pharmaceuticals Inc. Speaker's Bureau; Merck &amp; Co., Inc., Mercodia AB. Funding Nicolai J. Wewer Albrechtsen were financed by NNF Excellence Emerging Investigator Grant – Endocrinology and Metabolism (Application No. NNF19OC0055001) , EFSD Future Leader Award (NNF21SA0072746) and DFF Sapere Aude.

366-OR: 14-3-3-ζ Contributes to Effect of ß-Cell GLP1 Receptor Signaling to Alter a-Cell Proglucagon Processing

Glucagon like peptide 1 (GLP1) , a classically gut derived hormone, potentiates insulin secretion. New evidence suggests that α cells can produce GLP1 under certain conditions, which may offer a novel therapeutic modality for treating diabetes; however, the mechanisms regulating α cell GLP1 production are unknown. We previously found that enhanced β cell GLP1 receptor (GLP1R) signaling activates α cell GLP1 by activating prohormone convertase 1/3 (Pcsk1) expression. We tested the hypothesis that enhanced β cell GLP1R signaling activates α cell GLP1 production through paracrine factors. We studied the impact of conditioned media (CM) generated from β cell GLP1R WT and KO islets of saline (CTRL) and liraglutide (LIRA) treated mice on α cell gene expression and function. CM from LIRA treated islets increased α cell Pcsk1 expression and active GLP-1 secretion only if β cells expressed the GLP1R (Pcsk1 expression (AU) : CTRL WT=1.0±0.1, LIRA WT=2.0±0.3, CTRL KO=1.1±0.2, LIRA KO=1.1±0.2, P&amp;lt;0.01; active GLP-1 (pg/mL) : CTRL WT=124±44, LIRA WT=682±247, CTRL KO=173±101, LIRA KO=116±30, P&amp;lt;0.05) . Subsequent identification of the proteome secreted by mouse and human islets in response to LIRA and CTRL revealed 14-3-3-ζ as a lead candidate in the regulation of α cell Pcsk1 expression. To assess the role of 14-3-3-ζ, islets from LIRA treated mice were treated with and without 14-3-3-ζ, and islets from CTRL treated mice were treated with and without the 14-3-3 inhibitor, R18. Addition of 14-3-3-ζ ablated the effect of CM from LIRA treated islets to increase α cell Pcsk1 expression, while inhibition of 14-3-3 with R18 in CTRL islets resulted in CM that mimicked the effect of CM from LIRA treated islets to stimulate α cell Pcsk1 expression (Pcsk1 expression: CTRL=1.1±0.2, R18=2.0±0.2, LIRA=2.4±0.3, LIRA+14-3-3-ζ=1.3±0.1, P&amp;lt;0.05) . These data refine our understanding of α cell GLP1 regulation and identify 14-3-3-ζ as a potential target with which to enhance α cell GLP1 production for diabetes treatment. Disclosure M.Holter: None. B.Cummings: None. D.Phuong: None. I.S.H.Lee: None. M.Saikia: None. L.A.Weikert: Stock/Shareholder; Merck &amp; Co., Inc., Oramed Pharmaceuticals. E.T.Anderson: None. Q.Fu: None. S.Zhang: None. K.Sloop: Employee; Eli Lilly and Company. Funding NIH/NIDDK (F30 DK126538) Department of Defense (W81XWH-18-1-0206) The Hartwell Foundation NIH/NIDDK (R56DK124853)

31-OR: Almond Milk Has No Additional Benefits over 2% Milk on Postprandial Glycemia, Lipidemia, and Gastrointestinal Hormones in Patients with Type 2 Diabetes

Almond milk is often used in lieu of dairy milk with the perception of being a healthier substitute, however, its effect on postprandial glycemia compared to 2% milk is not understood. In this study, we compared the 4-hour postprandial effects of almond milk versus carbohydrate- or caloric-matched 2% milk, each served with a similar amount of oatmeal in patients with T2D. In this cross-over, three-way, open-label study, 22 overweight or obese patients with T2D consumed ½ cup (40 g) of oatmeal served with 360 mL almond milk (ALM) or carbohydrate-matched (246 ml) 2% milk (CarbM) or calorie-matched (182 ml) 2% milk, on separate days, in random order. The primary outcome was glucose incremental area under the curve (iAUC 0-240) while changes in other analytes were secondary outcomes. Blood samples for glucose, free fatty acids (FFA) , gastrointestinal (GI) satiety and hunger hormones were drawn at baseline, 15, 30, 60, 90, 120, 180 and 240 minutes. Incremental AUCs were compared between groups using Wilcoxon signed rank test. P-values for analytes other than glucose were adjusted with the false discovery rate (FDR) . P&amp;lt;5% for glucose or FDR&amp;lt;5% were considered significant. There were no differences in iAUC 0-240 for glucose, triglycerides, PYY, active GLP-1 or amylin, leptin, GIP, cholecystokinin, ghrelin or FFA in any pair-wise comparison. However, iAUC 0-240 for insulin and glucagon were significantly higher in CarbM vs. ALM (FDR 0.002 and 0.02 respectively) . In conclusion, compared to almond milk used with oatmeal, carbohydrate- or caloric-matched 2% milk has similar effects on postprandial glucose, FFA, triglycerides and GI hormones for up to 4 hrs, indicating no additional benefits of almond milk over 2% milk. On the contrary, carbohydrate-matched 2% milk increased insulin and glucagon secretion compared to almond milk. The long-term significance of this increase in insulin release needs to be further elaborated in a long-term study. Disclosure J.Mitri: Consultant; dairy management, Lnutra. S.Tomah: None. J.Dreyfuss: None. M.Al-badri: None. S.E.Dhaver: None. H.Gardner: None. M.Tasabehji: None. O.Hamdy: Advisory Panel; L-Nutra Inc., Nestlé, Consultant; Abbott, Sanofi, Research Support; Eli Lilly and Company, Gilead Sciences, Inc., National Dairy Council, Novo Nordisk, Stock/Shareholder; Healthimation.

1038-P: Exposures to Hyperglycemia in the Embryonic Period and to Breast Milk from Mothers with Hyperglycemia Affect Glucose Tolerance with Higher Glucagon-Like Peptide-1 Secretion

Exposure to hyperglycemia during pregnancy results in diabetes in offspring. However, its underlying mechanisms are unclear. We therefore focused on the glucose metabolism of the offspring who were exposed to hyperglycemia in uterus or who were breast-fed from mothers with hyperglycemia. ICR female mice received single intraperitoneal injection (i.p.) of streptozotocin at six weeks old as the model of mother with diabetes (MD) . An additional group of mice received citric acid buffer injection, instead, as the model of mother with normal glycemia (MNG) . We established the model exposed to hyperglycemia in the uterus (EHU) by switching offspring from MD to MNG right after birth. As the model exposed to the breast milk of mothers with hyperglycemia (EBM) , the offspring from MNG were moved to MD right after birth. To eliminate the effects of cross fostering, offspring from MNG were fostered by another MNG as the control group. In intraperitoneal glucose tolerance test (IPGTT) at P60, EHU and EBM didn’t show increase of blood glucose level (BG) nor decrease of plasma insulin level but showed in oral glucose tolerance test (OGTT) at P50 (AUC of BG: p &amp;lt; 0.in EHU, p &amp;lt; 0.00in EBM, AUC of plasma insulin level per BG: &amp;lt;0.00in EHU and EBM) . From these conflicting results, we suspected the participation of glucagon-like peptide-1 (GLP-1) . However, the AUC of plasma total GLP-1 and active GLP-1 levels were higher in OGTT. Since we didn’t observe any difference in beta cell area per whole pancreas section by immunostaining, EHU and EBM might have GLP-1 resistance. Disclosure K.Ishii: None. M.Odawara: Other Relationship; Astellas Pharma Inc., AstraZeneca, Daiichi Sankyo, Daiichi Sankyo, Dainippon Pharmaceutical Co., Ltd., Eli Lilly Japan K.K., Kowa Company, Ltd., Kyowa Kirin Co., Ltd., Merck &amp; Co., Inc., Mitsubishi Tanabe Pharma Corporation, Nippon Boehringer Ingelheim Co. Ltd., Novartis Pharma K.K., Novo Nordisk, Omnipod, ONO PHARMACEUTICAL CO., LTD., Sanofi K.K., Taisho Pharmaceutical Holdings Co., Ltd., Takeda Pharmaceutical Co.,Ltd., Teijin Pharma Limited. R.Suzuki: Consultant; Novo Nordisk A/S, Other Relationship; Daiichi Sankyo, Eli Lilly Japan K.K., MSD K.K., Ono Pharmaceutical Co., Ltd., Sanofi K.K., Sumitomo Dainippon Pharma Co., Ltd., Research Support; Boehringer Ingelheim Japan, Inc., LifeScan, Mitsubishi Tanabe Pharma Corporation. J.Sasaki: None. K.Sugai: None. M.Ito: None. H.Iwasaki: None. N.Hara: None. M.Aierken: n/a. G.Li: None. H.Suwanai: None.