Plasma Insulin Levels Research Articles

The role of fenugreek seed extract in alleviating pancreatic toxic effects and altering glucose homeostasis induced by acetamiprid via modulation of oxidative stress, apoptosis, and autophagy

Acetamiprid (ACMP) is a second-generation neonicotinoid that has been extensively used in the last few years. The present study examined the toxic effects of ACMP on the pancreas and glucose homeostasis through the evaluation of histological and biochemical changes and the possible ameliorative role of fenugreek seed extract (FG). Fifty adult albino rats were divided into 5 groups: negative control, positive control, FG-treated, ACMP-treated, and ACMP + FG-treated groups by oral gavage for 12 weeks. The ACMP-treated group highlighted significant elevations in plasma glucose, glycosylated haemoglobin levels (HbA1c), serum amylase, and serum lipase, along with a decrease in plasma insulin levels. In addition, significant increases in tumour necrosis factor- alpha (TNF-α) and malondialdehyde (MDA) were associated with reductions in the levels of interleukin 10 (IL-10), glutathione peroxidase, and catalase. Moreover, glucose-6-phosphatase and glycogen phosphorylase were significantly increased, with a significant reduction in hexokinase and liver glycogen stores. These biochemical changes were associated with histological changes in pancreatic sections stained by haematoxylin and eosin, Masson stain, and Orcein stain. ACMP-treated cells showed a marked reduction in β- cell immune reactivity to insulin, with pronounced p53, and beclin 1 immune expression. The use of FG with ACMP induced partial protection except for hexokinase and glycogen phosphorylase.

Bacoside-A Improves Antioxidant Enzymes and Alleviates Oxidative Stress Coexist with Markers of Renal Function in a Rat Model of Type 2 Diabetes Mellitus.

Oxidative stress, imbalanced antioxidants, and dysregulated renal lipids are closely linked with diabetic nephropathy and eventual cause of end-stage renal failure. This study was performed to investigate the protective effect of bacoside-A on markers of lipid peroxidation, renal lipids, and markers of renal function in diabetic rats. Experimental diabetes was induced in Wistar rats by a single dose of streptozotocin [40 mg/kg body weight (BW)] via intraperitoneal injection. Oral administration of bacoside-A (10 mg/kg BW) and glibenclamide, a reference drug, continued for 45 days. Diabetic rats showed a significant increase in the levels of plasma glucose, renal lipids, markers of renal lipid peroxidation, and plasma biomarkers of renal function such as urea, uric acid, and creatinine. A significant decrease in the levels of plasma insulin, nonenzymatic antioxidants, and the activity of enzymatic antioxidants was seen compared with the normal controls. Bacoside-A (10 mg/kg BW) and glibenclamide (600 μg/kg BW) administered to diabetic rats resulted in a significant decrease in plasma glucose and renal lipids but a significant increase in the plasma insulin level. In addition, bacoside-A achieved a remarkable increase in the activity of enzymatic antioxidants and the levels of nonenzymatic antioxidants in the renal tissue of diabetic rats, along with significant decreases in the markers of lipid peroxidation and those of renal function, consequently substantiating the protecting effectiveness of bacoside-A in a diabetic state. These biochemical observations were supported by a histopathological study of the renal tissue. The present study suggested that bacoside-A, a triterpenoid, offers a higher renoprotective effect to counter abnormal parameters of renal function in diabetes-induced renal injury.

Study of neuregulin-4 levels in newly diagnosed type 2 diabetes mellitus.

Neuregulin-4 is a recently recognized adipokine acting as ligands to tyrosine kinases receptor of the Erb B family. This adipose tissue augmented endocrine factor participates in the modulation of lipid and glucose metabolism and energy homeostasis. This novel adipokine is associated with insulin resistance, dyslipidemia, obesity, oxidative stress, and inflammation. The study aimed to compare plasma levels of neuregulin-4 in newly diagnosed type 2 diabetes mellitus as compared to matched controls and to correlate with glycemic and lipid parameters. 100 newly diagnosed T2DM patients and 100 age, sex, and BMI-matched controls after fulfilling all exclusion and inclusion criteria were included in the study. Fasting and postprandial blood glucose levels, glycated hemoglobin (HbA1c), and fasting plasma insulin levels were measured in both cases and controls. HOMA-IR values in both groups were calculated using fasting glucose and insulin levels. Mean levels of plasma neuregulin-4(pg/mL) in newly diagnosed T2DM were 7949.76 ± 949.76) pg/ml, which was significantly lower as compared to 9143 ±949.76) pg/ml in the control group (P-value <.0001). In the present study, a significant negative correlation was seen between plasma neuregulin-4 (pg/mL) with fasting blood sugar, postprandial blood sugar, HbA1C, and HOMA-IR with a correlation coefficient of -0.303, -0.416, -0.433, and -0.514, respectively. Moreover, a significant positive correlation was seen between plasma neuregulin-4 (pg/mL) with HDL with a correlation coefficient of 0.216. A significant negative correlation was seen between plasma neuregulin-4 (pg/mL) and LDL, with a correlation coefficient -0.208. Neuregulin levels are significantly lower in diabetics as compared to controls. There levels correlated inversely with HbA1C and HOMA IR.

The effect of evening primrose oil on some biochemical parameters in brain tissue in a model of metabolic syndrome induced with fructose in rats

Objective: Metabolic syndrome is a disease characterized by hypertension, dyslipidemia and insulin resistance, and constitutes an important risk factor for cardiovascular disorders. The effect of evening primrose oil (EPO) on insülin, adiponectin and resistin levels in brain tissue was investigated in a fructose-related metabolic syndrome model. &#x0D; Materials and Methods: The rats were divided into 4 groups as control, evening primrose oil (orally at a dose of 0.1 ml/rat/day), fructose (20% fructose added), fructose+evening primrose oil for 57 days. At the end of the experiment, brain samples were taken and homogenized. Then, insülin, adiponectin and resistin levels were determined by ELISA. &#x0D; Results: Plasma insulin and resistin levels of the fructose group increased (p≤0.05 ) compared to the controls, on the contrary, adiponectin levels were significantly decreased (p≤0.05 ) in the fructose group. When EPO was given to rats given fructose, increased insulin and resistin levels decreased, while decreased adiponectin levels were increased. &#x0D; Conclusion: Fructose-induced impaired metabolic changes in brain tissue were partially ameliorated when EPO was administered. Accordingly, the use of EPO in the medical setting may be recommended by clinicians to reduce the harmful effects on the brain, since metabolic changes in the brains of rat fed with high fructose content can also occur with the intake of fructose from various foods in humans.

Intestinal Electrical Stimulation Synchronized With Intestinal Slow Wave Ameliorates Glucagon-Induced Hyperglycemia in Rats

BackgroundSynchronized intestinal electrical stimulation (SIES), in which intestinal electrical stimulation (IES) is delivered in synchronization with the intrinsic slow wave of small intestine, was previously reported to be more potent in accelerating small intestine transit than IES delivered at fixed frequency and phase. We hypothesized that SIES is more potent in suppressing postprandial blood glucose by enhancing the release of glucagon-like peptide-1 (GLP-1) and insulin. Materials and MethodsRats underwent long-term implant of two pairs of electrodes at the duodenum for IES and SIES, respectively. Acute hyperglycemia was induced with glucagon, and the oral glucose tolerance test was performed on separate days with IES, SIES, or sham (no stimulation). Results1. Glucagon reduced the percentage of normal slow wave in sham (70.9% ± 4.1%) from (84.9% ± 2.6%, p = 0.006) of control, which was ameliorated by SIES (82.5% ± 3.3%, p = 0.031). 2. IES and SIES reduced glucagon-induced increase of blood glucose (192 mg/dl) at 30 minutes by 17% and 20%, respectively. SIES showed a further inhibitory effect at 60 minutes (147 vs 171 mg/dl, p = 0.003, vs sham). 3. Compared with sham (139 pg/ml), GLP-1 at 30 minutes was increased in both IES (158 pg/ml) and SIES (169 pg/ml). GLP-1 level was still high at 60 minutes in rats with SIES. 4. At 30 minutes, the plasma insulin level was increased by 18.8 μIU/ml with SIES, which was significantly higher than that with sham (7.1 μIU/ml, p < 0.001) and IES (13.2 μIU/ml, p = 0.041). ConclusionSIES is more effective than IES in reducing glucagon-induced acute hyperglycemia by enhancing the release of GLP-1 and insulin.

Naringenin protects pancreatic β cells in diabetic rat through activation of estrogen receptor β

Naringenin is a citrus flavonoid that potently improves metabolic parameters in animal models of metabolic disorders, such as type 2 diabetes. Estrogen receptor (ER) activation promotes β cell function and survival, thereby improving systemic glucose metabolism. In this study, we used a luciferase reporter assay, isolated rat islets and a diabetic rat model to investigate the effects of naringenin on ER signaling and the underlying mechanism of naringenin-mediated improvement of islet function in diabetes. Naringenin specifically activated ERβ without affecting the activity of ERα, G protein-coupled estrogen receptor (GPER) or estrogen-related receptor (ERR) α/β/γ. Additionally, treatment with naringenin enhanced glucose-stimulated insulin secretion in isolated rat islets. This effect was abrogated by PHTPP, an ERβ antagonist. Transcriptomic analysis revealed that naringenin upregulated the expression of genes, such as Pdx1 and Mafa, which are closely linked to improved β-cell function. In consistence, single administration of naringenin to normal rats elevated plasma insulin levels and improved glucose responses. These beneficial effects were blocked by PHTPP. In streptozocin-nicotinamide induced diabetic rats, treatment for 2 weeks with naringenin alone, but not in combination with PHTPP, significantly restored pancreatic β cell mass and improved glucose metabolism. Collectively, these data support that naringenin specifically activate ERβ to improve insulin secretion in the primary rat islets. Furthermore, naringenin administration also protected β cell function and reversed glucose dysregulation in diabetic rats. These beneficial effects are at least partially dependent on the ERβ pathway.

Effects of Treadmill Running at Different Light Cycles in Mice with Metabolic Disorders.

Type 2 diabetes mellitus accounts for about 90% of cases of diabetes and is considered one of the most important problems of our time. Despite a significant number of studies on glucose metabolism, the molecular mechanisms of its regulation in health and disease remain insufficiently studied. That is why non-drug treatment of metabolic disorders is of great relevance, including physical activity. Metabolic changes under the influence of physical activity are very complex and are still difficult to understand. This study aims to deepen the understanding of the effect of physical exercise on metabolic changes in mice with diabetes mellitus. We studied the effect of forced treadmill running on body weight and metabolic parameters in mice with metabolic disorders. We developed a high-fat-diet-induced diabetic model of metabolic disorders. We exposed mice to forced treadmill running for 4 weeks. We determined glucose and insulin levels in the blood plasma biochemically and analyzed Glut-4 and citrate synthase in M. gastrocnemius muscle tissue using Western blotting. The research results show that daily treadmill running has different effects on different age groups of mice with metabolic disorders. In young-age animals, forced running has a more pronounced effect on body weight. At week 12, young obese mice had a 17% decrease in body weight. Body weight did not change in old mice. Moreover, at weeks 14 and 16, the decrease in body weight was more significant in the young mice (by 17%) compared to the old mice (by 6%) (p < 0.05). In older animals, it influences the rate of glucose uptake. At 60 min, the blood glucose in the exercised older mice decreased to 14.46 mmol/L, while the glucose concentration in the non-exercised group remained at 17 mmol/L. By 120 min, in mice subjected to exercise, the blood glucose approached the initial value (6.92 mmol/L) and amounted to 8.35 mmol/L. In the non-exercised group, this difference was 45%. The effects of physical activity depend on the time of day. The greater effect is observed when performing shift training or exercise during the time when animals are passive (light phase). In young mice, light phase training had a significant effect on increasing the content of Glut-4 in muscle tissue (84.3 ± 11.3%, p < 0.05 with control group-59.3 ± 7.8%). In aged mice, shift training caused an increase in the level of Glut-4 in muscle tissue (71.3 ± 4.1%, p < 0.05 with control group-56.4 ± 10,9%). In the group of aged mice, a lower CS level was noticed in all groups in comparison with young mice. It should also be noted that we observed that CS increased during exercise in the group of young mice, especially during light phase training. The CS content in the light phase subgroup (135.8 ± 7.0%) was higher than in the dark phase subgroup (113.3 ± 7.7%) (p = 0.0006). The CS decreased in aged chow-fed mice and increased in the high-fat-fed group. The CS content in the chow diet group (58.2 ± 5.0%) was 38% lower than in the HFD group (94.9 ± 8.8%).

High-fat diet impairs glucose homeostasis by increased p16 beta-cell expression and alters glucose homeostasis of the progeny in a parental-sex dependent manner.

Obesity consists in the accumulation of adipose tissue accompanied by low grade chronic inflammation and is considered a pandemic disease. Recent studies have observed that obesity affects females and males in a sex-dependent manner. In addition, several works have demonstrated that parental obesity increases the risk to develop obesity, insulin resistance, diabetes, and reproductive disorders. Considering that intergenerational effects of obesity may occur in a sex-dependent manner, we studied male Wistar rat progeny (F1) obtained from mothers or fathers (F0) fed on a high-fat diet (HFD). Five-week-old female and male Wistar rats were fed on a HFD (with 60% of calories provided by fat) for 18 weeks (F0). At the end of the treatment, animals were mated with young rats to obtain their progeny (F1). After weaning, F1 animals were fed on standard chow until 18 weeks of age. Body weight gain, fasting plasma glucose, insulin and leptin levels, glucose tolerance, insulin sensitivity, and adiposity were evaluated. In addition, beta-cell expression of nuclear p16 was assessed by immunofluorescence. HFD altered plasma fasting glucose, insulin and leptin levels, glucose tolerance, adiposity, and beta-cell expression of p16 in F0 rats. Particularly, HFD showed sexual dimorphic effects on body weight gain and insulin sensitivity. Moreover, we observed that parental HFD feeding exerts parental-sex-specific metabolic impairment in the male progeny. Finally, parental metabolic dysfunction could be in part attributed to the increased beta-cell expression of p16; other mechanisms could be involved in the offspring glucose homeostasis.

β cell function and insulin resistance have gender-specific correlations with carotid intima-media thickness in type 2 diabetes

ObjectiveThe relationships between carotid intima-media thickness (C-IMT) and β cell function and insulin resistance in patients with type 2 diabetes (T2D) have not been fully elucidated. This study is to investigate whether impaired glucose metabolism is etiologically associated with C-IMT in patients with T2D.MethodsThe study group consisted of 490 (284 men, 206 women) participants. Venous blood specimens were obtained from all subjects for biochemical profiles after an >8-h overnight fast. C-IMT was measured as the distance between the luminal-intimal leading edge (I-line) and the medial-adventitial leading edge (M-line) on the far wall. Insulin resistance was estimated with the homeostasis model assessment of insulin resistance (HOMA-IR). The acute insulin response to arginine was calculated as the mean of the three plasma insulin levels obtained within 2, 4, and 6 min after the arginine bolus minus the pre-stimulus plasma insulin levels.ResultsThere was a graded increase in C-IMT values according to tertiles of HOMA-IR in men; the values of C-IMT were significantly decreased across the tertiles of acute insulin and C-peptide responses in women. Multivariate analysis revealed that HOMA-IR and age were positively associated with C-IMT among men participants, and acute insulin response and current smoking were the independent determinants of C-IMT in women.ConclusionEarly insulin response stimulated by arginine is independently associated with C-IMT in women T2D individuals, whereas insulin resistance is positively correlated with C-IMT in men T2D subjects.

OR12-06 Hypothalamic Adgrl1 Is A Potential Glucoreceptor Involved In Regulating Energy Balance, Glucose Homeostasis, And Leptin Sensitivity In Mice

Abstract Disclosure: D.J. Samuel: None. T.S. Faniyan: None. M.U. Raza: None. S. Bathina: None. K.H. Chhabra: None. The hypothalamus regulates energy and glucose homeostasis by influencing glucose-stimulated insulin secretion, insulin sensitivity, and activating the hypoglycemia counterregulatory response. Although hypothalamic glucose transporters coupled with glucose metabolism are involved in mediating some of these effects, it is unknown whether a plasma membrane receptor that directly binds to glucose can contribute to hypothalamic glucose signaling. We used affinity chromatography and biotin-labeled glucose to enrich glucose-binding plasma membrane proteins/receptors in the mouse hypothalamus and then performed proteomic analyses. Adhesion G-protein Coupled Receptor L1 (Adgrl1) was a top candidate as a potential glucoreceptor. Therefore, we generated Adgrl1loxp/loxp mice to knockout Adgrl1 in the ventromedial hypothalamus (VMH; a region known for glucose sensing) using the Cre-Lox system to determine the role of Adgrl1VMH in glucose homeostasis, energy balance, and leptin sensitivity. We measured body weight, food intake, 6h fasting blood glucose and plasma insulin levels. We also determined leptin sensitivity in the Adgrl1VMH deficient mice. We observed that 24 weeks old male Adgrl1VMH deficient mice had higher (p&amp;lt;0.05) body weight (49 ±3.6 vs 35 ±1.3 g), blood glucose (210 ±4 vs 180 ±5 mg/dl), plasma insulin levels (2.92 ±0.24 vs 1.63 ±0.09 ng/ml), and leptin levels (21.11 ±1.72 vs 8.38 ±0.80 ng/ml) compared to their control littermates. Hyperinsulinemia and hyperleptinemia persisted in the Adgrl1VMH knockout mice even when they were weight-matched to their littermate controls, indicating the direct role of Adgrl1VMH in regulating plasma insulin and leptin levels. Ovariectomy in female mice was necessary to unmask the effects of Adgrl1VMH deficiency on energy and glucose homeostasis. To assess acute leptin sensitivity, we injected Adgrl1VMH deficient mice and their littermate control mice with recombinant mouse leptin (5 mg/Kg, i.p., twice a day for two days), and monitored their body weight and food intake. Male Adgrl1VMH deficient mice were more susceptible (p&amp;lt;0.05) to leptin mediated decrease in food intake (-1 ±0.1 vs -0.5 ±0.005, g/day; these values are relative to each group’s corresponding baseline food intake) than their littermate controls. Decrease in body weight was similar in both groups with this acute leptin treatment. These findings suggest that Adgrl1VMH is essential in regulating energy and glucose homeostasis in a sex-specific manner. Moreover, Adgrl1VMH contributes to leptin’s acute effects on food intake. Therefore, hypothalamic Adgrl1 could be a target to enhance leptin sensitivity in future therapies for treating type 2 diabetes and obesity. Presentation: Friday, June 16, 2023

SAT072 Choline Deprivation Aggravates Hyperglycemia And Fatty Liver In Non-obese Streptozocin-induced Diabetic Rats

Abstract Disclosure: C. Liapi: None. A. Kyriakaki: None. H. Al Humadi: None. R. Al-Saigh1: None. A. Al Humadi: None. A. Lazaris: None. Background: Choline deprivation (CD) is an established model of steatohepatitis. There is a strong association between non-alcoholic fatty liver disease and diabetes mellitus that has a significant impact on the global health system. The combined state of CD and diabetes can resemble common cases in clinical practice including parenteral nutrition, pregnancy, chronic liver disease malnutrition and/ or alcoholism in diabetic individuals. The aim of this study was to investigate the effects of choline deprivation on glycemic control, insulin signaling pathway and lipid metabolism in non-obese streptozocin-induced diabetic rats. Methods: Thirty-two male adult Wistar rats were divided into four groups; control, diabetes (DM), choline-deprived diet (CDD), and combined group (DM+CDD); DM was induced by intraperitoneal streptozotocin administration. Body weight, fasting blood glucose and plasma insulin levels, lipid profile, liver biochemistry, liver histopathology and gene expression of insulin receptor (IR), insulin receptor substrate-1 (IRS-1), glucose transporters 2 &amp; 4 (GLUT-2 &amp; -4) in hepatic tissue, were assessed. Results: The combination group (CDD+DM) showed a significant increase in blood glucose associated with a significant decrease in plasma insulin level and evidence of dyslipidemia with a significant increase in liver enzymes, histopathology showed extensive micro- and macrovesicular steatosis and a significant decrease in weight gain versus the control, CDD and DM group. A significant increase was observed in gene expression of IR, IRS-1, GLUT-2, and GLUT-4 in all the experimental groups versus the control. Conclusion: The combination of choline deficiency and diabetes has drawn some new scenarios on insulin and some hepatic metabolic pathways: (i) plasma insulin resistance with progressive hyperglycemia and hyperlipidemia.(ii) attenuation of hepatic insulin resistance or sensitization of insulin signaling pathways in the liver, due to the hepatotoxic effects of choline deficiency that could ultimately simulate features of the metabolic syndrome, and (iii) experimentally simulation of metabolic conditions seem to act synergistically, leading to poor glycemic control along with aggravation of hepatic steatosis. Presentation: Saturday, June 17, 2023

SAT043 Chronically High Cerebrospinal Fluid Glucose Levels Impair Memory In Male Mice

Abstract Disclosure: M.U. Raza: None. K.H. Chhabra: None. Diabetes doubles the risk of cognitive decline and Alzheimer’s disease (AD). Whether this is mediated by an increase in blood glucose or cerebrospinal fluid (CSF) glucose levels, or by other metabolic factors such as changes in plasma insulin levels is unclear. To clarify the contribution of high blood glucose versus high CSF glucose levels toward increasing the risk of cognitive decline in mice, we have developed a method through which glucose concentration can be increased selectively in CSF. We implanted 8 weeks old male mice (n= 7-8 / group) with cannula attached to osmotic minipumps to directly infuse either artificial CSF (aCSF/sham group) or 50% glucose solution (treatment group) into the right lateral ventricle for eight weeks at a flow rate of 0.25ul/hr. CSF glucose was measured two and eight weeks after initiating the infusion in these mice. We also performed oral glucose tolerance tests (OGTT) in these mice to assess their peripheral glucose metabolism and uptake. Moreover, these mice were tested through the Morris water maze (MWM) to investigate the effects of high CSF glucose on learning and memory. Mice in the treatment group showed a significant increase (p&amp;lt;0.0001, unpaired t-test) in CSF glucose levels (mean=328±30.15 and 358±15.03mg/dl post-2, and 8 weeks of implantation, respectively) as compared to the sham group (mean=56±2.63 and 73±8.61mg/dl post-2, and 8 weeks of implantation, respectively). There was no significant change in body weight and food intake during the study. In OGTT, the treatment group showed significantly lower blood glucose levels (p&amp;lt;0.05, two-way ANOVA repeated measures design, Bonferroni’s multiple comparisons) at 15 minutes post-gavage (mean=336.3±24.41mg/dl) as compared to the sham group (mean=478.6±30.06 mg/dl). Mice in the treatment group made significantly fewer entries to the correct quadrant (i.e. the quadrant where the hidden platform was placed during training) (mean=12.43±1.55 entries, p&amp;lt;0.05, unpaired t-test) in the MWM test, as compared to the sham group (mean=18.4±1.84 entries). Additionally, mice in the treatment group were significantly less likely to revisit the correct quadrant (mean=10.7±1.50 revisits, p&amp;lt;0.05, unpaired t-test) than the mice in the sham group (mean=16.8±1.78 revisits). Importantly, there was no significant difference in the overall locomotor activity between the groups as measured through the open field test. To summarize, we have developed a method to test the effects of high CSF glucose levels on learning and memory in mice. Our results show that high CSF glucose levels for up to two months cause memory deficits in mice. This mouse model of chronically high CSF glucose presents a useful tool to investigate how diabetes-associated dysregulation of glucose homeostasis in the brain may contribute to AD and other neurodegenerative disorders. Presentation: Saturday, June 17, 2023

SAT038 Dietary Trans-10,cis-12 Conjugated Linoleic Acid Regulates Glucose Levels In Mice With Severe Insulin Resistance: Potential Effects On The Liver Via HNF4α And FOX01

Abstract Disclosure: S.M. Lee: None. J.T. Muratalla: None. C.W. Liew: None. J. Cordoba-Chacon: None. Plasma trans-10 cis-12-conjugated linoleic acid CLA (t10c12-CLA) is inversely associated with increased risk of diabetes in humans. In mice, it is well-known that t10c12-CLA induces whole-body insulin resistance due to severe lipodystrophy (loss of whole-body adipose tissue). However, t10c12-CLA-fed mice show normal glucose levels and, t10c12-CLA improved glucose clearance in models with preexisting insulin resistance: Zucker fatty/diabetic rats, obese and insulin resistant Ldlr-/- mice, and diet-induced obese and insulin resistant male mice. In this study, we assessed whether supplementation of t10c12-CLA in a low-fat diet reduces glucose levels in adipocyte-specific insulin receptor knockout (IRFKO) mice, which is a mouse model of congenital lipodystrophy. In addition to lipodystrophy, IRFKO mice show liver steatosis and increased blood glucose levels that are consequences of whole-body insulin resistance and increased hepatic gluconeogenesis. Briefly, 5-6-week-old male and female control and IRFKO mice were fed with a low-fat diet supplemented with 0.8% t10c12-CLA for 5 weeks. In IRFKO mice, dietary t10c12-CLA did not reduce adipose tissue mass. However, dietary t10c12-CLA increased liver steatosis and plasma insulin levels. Surprisingly, dietary t10c12-CLA reduced glucose levels in both male and female IRFKO mice. Also, dietary t10c12-CLA reduced food intake and polydipsia, which were increased in IRFKO mice due to lipodystrophy and hyperglycemia, respectively. A transcriptomic analysis (RNA-seq) of livers of control and IRFKO male mice fed with a t10c12-CLA diet showed that t10c12-CLA reduced the expression of the key gluconeogenic and mitochondrial fatty oxidation genes. Previous studies have suggested that t10c12-CLA reduces the expression of Forkhead box 01 (Fox01) and Hepatocyte nuclear factor 4 alpha (HNF4α). Of note, the livers of t10c12-CLA-fed control and IRFKO male mice showed a downregulation of positive targets of FoxO1 and HNF4α. In addition, livers of t10c12-CLA-fed mice showed reduced total FOXO1 protein levels, and increased phosphorylation of FOXO1 in t10c12-CLA-fed IRFKO mice. These findings suggest that t10c12-CLA could be directly acting on the liver to alter HNF4α and FOXO1-dependent regulation of hepatic fatty acid oxidation and glucose production. These actions may explain why t10c12-CLA-fed mice do not show increased glucose levels and is potentially linked to the inverse association between t10c12-CLA levels and diabetes risk. Presentation: Saturday, June 17, 2023

SAT163 Title: Adult-onset Hyperinsulinemic Hypoglycemia Due To An Activating Mutation In Glucokinase

Abstract Disclosure: S. Vaid: None. R. Ghosh: None. H. Elenius: None. C. Cochran: None. R. Chang: None. N. Nilubol: None. R. Muniyappa: None. Introduction: Glucokinase (GK), the key β-cell glucose sensor, determines the threshold for glucose-stimulated insulin secretion. Activating mutations of GK are infrequent causes (prevalence of 1.2%) of congenital hyperinsulinemic hypoglycemia (HH). Adult-onset of severe hypoglycemia due to GK-HH is extremely rare. Clinical Case: A 26-year-old well-nourished female (BMI, 27 kg/m2) with a recent history of dizziness, tremulousness, fatigue, sweating, and hunger, associated with weight gain presented for further workup. Hypoglycemia was noted, and Whipple's triad was confirmed. She had no family history of endocrine disease or hypoglycemia. Supervised fasting promptly produced symptomatic hypoglycemia with hyperinsulinemia. Laboratory studies revealed a low glucose level at 44 mg/dL; a plasma insulin level at 93 μIU/mL (&amp;lt;3 μIU/ml); a C-peptide level at 8.1 ng/mL (&amp;lt;0.6 ng/mL); pro-insulin at 266 pmol/L (&amp;lt;5 pmol/L); and beta-hydroxybutyrate &amp;lt;2.7 mmol/L. IGF2/IGF-1 ratio was 3.1 (&amp;lt;10) and renal and liver function was normal. Interestingly, a mixed meal also provoked significant hypoglycemia within an hour of consumption of a meal. Urine for sulfonylurea screen was negative, and so were anti-insulin antibodies. Imaging of the pancreas with computed tomography (CT), magnetic resonance imaging (MRI), and endoscopic ultrasound revealed a 1.2x0.8cm nodule on the superior margin of the body of the pancreas. 68Ga-DOTATATE​​ PET/CT (targeting somatostatin receptors) showed mild uptake coinciding with the nodule on the CT scan. Arteriography with calcium stimulation and venous sampling (ASVS) was non-localizing. The patient subsequently underwent laparoscopic exploration with intraoperative ultrasound (IOUS) of the pancreas followed by the enucleation of the pancreatic nodule. Histopathology of the nodule revealed a normal pancreatic tissue with no evidence of a neuroendocrine tumor. Change to multiple small meals, addition of cornstarch to diet, continuous blood glucose monitoring (CGM), diazoxide (70 mg oral, three times a day), and monthly octreotide LAR (30 mg) has allowed the patient to avoid hypoglycemia. Genetic testing by analysis of the genes known to cause hypoglycemia revealed a heterozygous GCK variant [c.1367C&amp;gt;T (p.Ala456Val), which was predicted to be a pathological mutation. This mutation is known to increase affinity for glucose, which leads to exaggerated insulin secretion. Conclusion: Our study highlights that in adults with non-insulinoma pancreatogenous hypoglycemia, genetic causes of HH should be considered in the differential diagnosis. Presentation: Saturday, June 17, 2023

SAT029 Goldfish Phoenixin: Role In Feeding Control And Its Regulation At The Hepatic Level

Abstract Disclosure: X. Qin: None. C. Ye: None. M. He: None. W.K. Ko: None. A.O. Wong: None. Phoenixin (PNX), a novel peptide first identified by bioinformatics, is known to have pleiotropic functions and its biological actions are mediated via the orphan receptor GPR173. At present, the study of PNX in non-mammalian species, especially in lower vertebrates, is limited and hormone regulation of PNX as well as the post-receptor signalling involved are still unclear. Using goldfish as a model for bony fish, two forms of PNX, PNXa &amp; b, and one form of GPR173 were cloned. Phylogenetic analysis confirmed that goldfish PNXa, PNXb &amp; GPR173 could be clustered in respective clades of target genes in fish species. Alignment of a.a. sequences and 3D protein modelling also revealed that goldfish PNXa &amp; b were highly comparable to PNX reported in other vertebrates. Using RT-PCR, PNXa/b &amp; GPR173 were found to be ubiquitously expressed at tissue level. For functional testing, PNXa &amp; b were synthesized and tested for their effects on feeding control by IP injection in goldfish. In this case, parallel rises in foraging behaviours and food intake were noted after PNX treatment. Similar results were also obtained with ICV injection of PNXa &amp; PNXb, respectively. In goldfish, food intake could elevate plasma levels of glucose, insulin, growth hormone (GH) and IGF-I with parallel rises in transcript expression of GH in the pituitary and PNXa, PNXb, insulin &amp; IGF-I mRNA in the liver. In goldfish hepatocytes, insulin and IGF-I were both effective in up-regulating PNXa &amp; b mRNA expression via activation of IGF-I receptor (IGF1R) but not insulin receptor. Using a pharmacological approach, IGF-I induced PNXa &amp; b gene expression could be blocked by the inhibitors for PI3K, Akt and mTor but not by the inhibitors for MEK1/2, ERK1/2 and P38MAPK. Our results, as a whole, indicate that (i) PNX &amp; GPR173 are co-expressed in goldfish at tissue level &amp; involved in feeding induction, presumably via central action in the brain, (ii) food intake can up-regulate hepatic expression of PNXa &amp; b via insulin signal caused by glucose uptake and parallel activation of the GH/IGF-I axis after feeding, and (iii) hepatic expression of PNXa &amp; b induced by insulin/IGF-I signal is mediated via IGF1R functionally coupled with the PI3K/Akt/ mTOR but not MEK/ERK &amp; P38MAPK pathways. Presentation: Saturday, June 17, 2023

THU269 Ethnic Differences In Hepatic Insulin Clearance: A Cross-Sectional Study Comparing South Asians And Non-Hispanic Whites

Abstract Disclosure: A.L. Ramanathan: None. H. Fan: None. R. Muniyappa: None. Background: Hepatic insulin clearance homeostaticallyregulates peripheral plasma insulin concentration. Reduced or impaired insulinclearance promotes insulin resistance and hyperinsulinemia, which increase therisk of type 2 diabetes mellitus (T2DM). South Asians (SA) have an elevatedrisk and prevalence of T2DM compared to other ethnic groups, but insulinclearance by ethnicity has not yet been investigated. Our cross-sectional studyexamines insulin clearance in SA compared to non-Hispanic whites (NHW) todetermine ethnic differences in hepatic extraction in both the fasting andpostprandial states. Methods: Thirty healthy SA (age: 39.1 ± 9.4; female: n=12;BMI: 27.7 ± 4.8 kg/m2) and thirty healthy NHW (age: 39.2 ± 11.4;female: n=12; BMI: 26.7 ± 5.3 kg/m2) underwent mixed meal tolerancetests (MMTT) to determine plasma glucose, insulin, and C-peptide levels. Wederived parameters of hepatic clearance using a C-peptide kinetics model, aninsulin secretion model, and an insulin kinetics three-compartmental model. Model parameters included distribution volume of insulin (Vp), control ofplasma glucose on hepatic extraction (aG), basal hepatic extraction levels(HEb), and total hepatic extraction levels (HEtot). Differences by ethnicity werecalculated using an unpaired t-test for parametric variables and a Mann-Whitneytest for nonparametric data. Results: Fasting glucose (93.7 ± 9.77 vs. 89.0 ± 6.96 mg/dL,p=0.06) and fasting insulin (13.30 ± 8.04 vs. 6.58 ± 6.61 mu/mL, p&amp;lt;0.001)were higher in SA. Insulin area under the curve during MMTT was also elevatedin SA (12608 ± 6031 vs. 5892 ± 3533 min*mU/mL, p&amp;lt;0.001). Calculated mean Vp(0.0365 ± 0.0133 vs. 0.0564 ± 0.0130 kg-1, p&amp;lt;0.0001), mean aG(0.2001 ± 0.0409 vs. 0.2285 ± 0.0556 mmol-1, p=0.03), and basalhepatic extraction (54.9 ± 22.6 vs. 65.6 ± 18.8%, p=0.04) were lower in SA.Total hepatic extraction during MMTT was not different between SA and NHW(p=0.33). Conclusions: SA have reduced basal hepatic clearancecompared to NHW, although total extraction remained similar between the twogroups during MMTT. Further investigations are needed to derive accurateinsulin clearance parameters for ethnic groups with elevated T2DM risk. Presentation: Thursday, June 15, 2023

OR22-03 Enhanced Endothelial Mineralocorticoid Receptor Signaling Mediates Diet - Induced Soleus Fat Infiltration And Insulin Resistance

Abstract Disclosure: C. Homan: None. J. Habibi: None. D. Chen: None. A. Whaley-Connell: None. J.R. Sowers: None. G. Jia: None. Skeletal muscle is an important organ in the storage and release of lipids in response to physiological changes in free fatty acid (FFA) supply and demand. Once fat tissue mass expansion exceeds its blood supply excess lipids are stored ectopically as small lipid droplets in non-adipose tissues such as skeletal muscle. Recently, our data found that mineralocorticoid receptors (MRs) mediate Western diet (WD)-induced lipid infiltration of skeletal muscle and insulin resistance. Related to this, MRs, the principal receptors for the hormone aldosterone in the kidney, also exist in vascular cells, including endothelial cells (ECs). Moreover, enhanced MR signaling in ECs (ECMR) induces arterial stiffening and impairs microcirculation. However, our understanding of the precise mechanisms by which enhanced ECMR activation promotes skeletal muscle insulin resistance remains unclear. In this study we investigated the roles of ECMR in soleus lipid accumulation and corresponding insulin resistance in diet-induced obesity. Six-week-old ECMR wild type (ECMR+/+) and knockout (ECMR-/-) mice were fed either a mouse chow diet or WD for 16 weeks. 16 weeks of WD induced increases in glucose intolerance, fasting plasma insulin levels, HOMA-IR and insulin resistance index were found to be blunted in ECMR-/- mice. ECMR-/- prevented WD-induced increase in soleus FFA levels without changing serum FFA levels. Meanwhile, WD also increased soleus intramyocellular lipid content, plasma EC derived exosomal CD36 and soleus CD36 protein levels. These abnormalities were related to reduced soleus insulin metabolic signaling in PI3K/Akt pathways, as these pathways were blunted in ECMR-/- mice. These findings indicate that EC specific MR activation contributes to diet-induced increases in CD36 expression, soleus fat infiltration, as well as systemic and skeletal muscle insulin resistance. Presentation: Saturday, June 17, 2023

Postpartum defects in inflammatory response after gestational diabetes precede progression to type 2 diabetes: a nested case-control study within the SWIFT study

BackgroundGestational diabetes (GDM) is a distinctive form of diabetes that first presents in pregnancy. While most women return to normoglycemia after delivery, they are nearly ten times more likely to develop type 2 diabetes than women with uncomplicated pregnancies. Current prevention strategies remain limited due to our incomplete understanding of the early underpinnings of progression. AimTo comprehensively characterize the postpartum profiles of women shortly after a GDM pregnancy and identify key mechanisms responsible for the progression to overt type 2 diabetes using multi-dimensional approaches. MethodsWe conducted a nested case-control study of 200 women from the Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy (SWIFT) to examine biochemical, proteomic, metabolomic, and lipidomic profiles at 6–9 weeks postpartum (baseline) after a GDM pregnancy. At baseline and annually up to two years, SWIFT administered research 2-hour 75-gram oral glucose tolerance tests. Women who developed incident type 2 diabetes within four years of delivery (incident case group, n = 100) were pair-matched by age, race, and pre-pregnancy body mass index to those who remained free of diabetes for at least 8 years (control group, n = 100). Correlation analyses were used to assess and integrate relationships across profiling platforms. ResultsAt baseline, all 200 women were free of diabetes. The case group was more likely to present with dysglycemia (e.g., impaired fasting glucose levels, glucose tolerance, or both). We also detected differences between groups across all omic platforms. Notably, protein profiles revealed an underlying inflammatory response with perturbations in protease inhibitors, coagulation components, extracellular matrix components, and lipoproteins, whereas metabolite and lipid profiles implicated disturbances in amino acids and triglycerides at individual and class levels with future progression. We identified significant correlations between profile features and fasting plasma insulin levels, but not with fasting glucose levels. Additionally, specific cross-omic relationships, particularly among proteins and lipids, were accentuated or activated in the case group but not the control group. ConclusionsOverall, we applied orthogonal, complementary profiling techniques to uncover an inflammatory response linked to elevated triglyceride levels shortly after a GDM pregnancy, which is more pronounced in women who progress to overt diabetes.

Effects of Kudzu Root on Oxidative Stress and Inflammation in Streptozotocin-induced Diabetic Rats

Background: Oxidative stress and inflammation are strictly connected, and both perform an important role in the pathogenesis of diabetes mellitus (DM). Objectives: This research aimed to investigate the potential protective effect of kudzu root against oxidative stress and inflammation in a streptozotocin (STZ)-induced DM animal model. Methods: DM was induced in male Wistar rats by intraperitoneal injection of STZ (50 mg/kg body weight). The kudzu root (100 mg/kg BW) was administered orally after 1 week of STZ administration in diabetic animals (for 6 weeks). Results: The diabetic animals exhibited a significant increase in fasting blood glucose, tumor necrosis factor-alpha, and malondialdehyde levels. However, they exhibited a significant decrease in plasma insulin level, superoxide dismutase, and glutathione peroxidase activity. Administration of kudzu root to diabetic animals reversed these effects. Conclusion: The current study indicated that kudzu root has potent antidiabetic properties, likely through its anti-inflammatory and anti-oxidative properties in the STZ-diabetic rat model.

Anti-diabetic effect of Ornithogalum caudatum Jacq. polysaccharides via the PI3K/Akt/GSK-3β signaling pathway and regulation of gut microbiota

This study evaluated the anti-diabetic effect of polysaccharides isolated from Ornithogalum caudatum and their underlying mechanisms. To achieve this, a type 2 diabetes mellitus mouse model was established using a combination of a high-fat diet and low-dose streptozotocin injection. The mice were treated with Ornithogalumcaudatum polysaccharides (OCPs) for 4 weeks. OCPs treatment significantly decreased body weight loss, fasting blood glucose levels, and plasma insulin levels in diabetic mice. Additionally, compared with the untreated group, OCPs treatment significantly decreased total cholesterol, triacylglycerol, and low-density lipoprotein-cholesterol levels, but increased those of high-density lipoprotein-cholesterol in diabetic mice. Moreover, antioxidant enzyme activity and histopathology results revealed that OCPs effectively alleviated oxidative stress and streptozotocin-induced lesions by increasing antioxidant enzyme activity. Results from mechanistic studies showed that OCPs treatment significantly increased the expression of p-PI3K, p-Akt, and p-GSK-3β in the liver. Moreover, OCPs optimized the gut microbiota composition of diabetic mice by significantly decreasing the Firmicutes/Bacteroidetes ratio and increasing the levels of beneficial bacteria (Muribaculaceae_norank, Prevotellaceae_UCG-001 and Alloprevotella). Overall, these findings suggest that OCPs exert anti-diabetic effects by triggering the PI3K/Akt/GSK-3β signaling pathway and regulating the gut microbiota.