Glucose Homeostasis In Rats Research Articles

Lipid Profile and Blood Glucose Levels of Wistar Rats Fed a Non-High Fat Nutriment Supplemented with Black Garlic Extract

Many studies related to the therapeutic effect of black garlic (BG) have been carried out on cancer, diabetes, neurodegenerative, cardiovascular, dyslipidemia and other diseases. This investigation was conducted to examine the effect of BG supplements on the lipid profile and blood glucose of rats fed a customary diet (non-high fat diet). A fermented black garlic product was extracted by a maceration method and its phytochemical components were analyzed using LCMS. Black garlic extract was given to healthy rats with a normal feed for 14 days. Twenty-four rats were divided into 4 groups of 6 rats. As a control, group A was given aquadest (placebo), and groups B, C, and D were given BG extract at a dose of 15 mg/kg BW, 30 mg/kg BW, and 45 mg/kg BW, respectively. On day 15, blood was taken from the retro-orbital plexus of the rats to measure the total levels of cholesterol, High-Density Lipoprotein-Cholesterol (HDL-C), Triglyceride (TG), Low-Density Lipoprotein-Cholesterol (LDL-C) and glucose. Black garlic made by fermentation at 80°C for 8 days contained more monosaccharides, disaccharides and oligosaccharides than fresh garlic. Black garlic contained 32 types of organosulfur compounds, and the 5 most abundant compounds were allicin (5.813%), allin (4.993%), isoallin (3.77%), cycloalliin (3.163%) and (-) S-allyl-L-cysteine (2.022%). Black garlic extract administration was able to maintain blood glucose homeostasis in rats fed a normal diet (non-high fat diet). Levels of total cholesterol, triglyceride, and LDL-C were significantly decreased in groups administered black garlic compared to the control group, whilst the level of HDL-C increased significantly in groups administered black garlic compared to the control group.

Regulation of Intestinal Flora and Immune Response by Cyanidin Exhibits Protective Effect against Type-2 Diabetes in Rat Model.

In the current study the effects of metformin and cyanidin on the immune system and intestinal flora in rats with type-2 diabetes was investigated. The findings showed that metformin or cyanidin treatment considerably reduced the rise in body weight and glucose levels induced by type-2 diabetes. The type-2 diabetic rats' glucose tolerance was significantly increased by cyanidin administration comparable to that of metformin. Cyanidin administration resulted in a significant reduction in serum cholesterol and low-density lipoprotein (LDL) levels in rats with type-2 diabetes. Treatment with cyanidin significantly increased the ratio of high-density lipoprotein to low-density lipoprotein in type-2 diabetes rats. Cyanidin administration significantly raised the ratio of Firmicutes to Bacteroidetes in the fecal samples of type-2 diabetic rats compared to the model group. In comparison to the model group, it also significantly raised the levels of Lactobacillus intestinalis, Lactobacillus gasseri, and Lactobacillus reuteri in the type-2 diabetes rats. In type-2 diabetes rat fecal samples, the abundance of Christensenellaceae significantly increased while Enterobacteriaceae and Proteobacteria were found to decrease upon cyanidin administration. Furthermore, cyanidin administration to the rats with type-2 diabetes significantly improved the glucose homeostasis. In conclusion, the study demonstrates that cyanidin enhances glucose homeostasis in rats with type-2 diabetes, potentially through controlling intestinal flora. Thus, cyanidin may be looked into more as a possible therapeutic agent for type 2 diabetes.

Effects of central FGF21 infusion on the glucose homeostasis in rats (brain–pancreas axis)

Introduction Glucose homeostasis is a physiological process mediated by a variety of hormones. Fibroblast growth factor (FGF) 21 is a protein expressed in the liver, adipose tissue, muscle and pancreas and exerts actions in multiple targets including adipose, liver, pancreas and hypothalamus. The aim of this study was to examine the possible involvement of FGF21 in pancreatic and central control of glucose by measuring reflective changes in the release of insulin and glucagon. Methods Thirty adult male Wistar Albino rats were divided; Control, PD + aCSF, PD + FGF21 groups (n = 10). Effects of intracerebroventricular (icv) FGF21 administration to pancreatic denervated (PD) rats. Agouti-related protein (AgRP), Pro-opiomelanocortin (POMC) levels and blood glucose homeostasis were investigated. Results Administration of FGF21 to 3rd ventricle increased food consumption but body weight didn’t change significantly. AgRP level increased, pancreatic insulin levels increased, and glucagon level decreased. Conclusion Central FGF21 administration is effective in regulating blood glucose homeostasis by increasing the amount and efficiency of insulin and changing glucose use.

Modulation of Glucose Homeostasis in Rats Treated with Bacterial Lipopolysaccharide: Role of L-Arginine Counter-Strategy

Modulation of Glucose Homeostasis in Rats Treated with Bacterial Lipopolysaccharide: Role of L-Arginine Counter-Strategy

Preconception exposure to malathion and glucose homeostasis in rats: Effects on dams during pregnancy and post-term periods, and on their progeny.

Understanding the individual and global impact of pesticides on human physiology and the different stages of life is still a challenge in environmental health. We analyzed here whether administration of the organophosphate insecticide malathion before pregnancy could affect glucose homeostasis during pregnancy and, in addition, generate possible later consequences in mothers and offspring. For this, adult Wistar rats were allocated into two groups and were treated daily (intragastric) with malathion (14 or 140 mg/kg, body mass (bm)) for 21–25 days. Corn oil was used as vehicle in the Control group. Subgroups were defined based on the absence (nulliparous) or presence (pregnant) of a copulatory plug. Pregnant rats were followed by an additional period of 2 months after the term (post-term), without continuing malathion treatment. Fetuses and adult offspring of males and females were also evaluated. We ran an additional experimental design with rats exposed to malathion before pregnancy at a dose of 0.1 mg/kg bm. Malathion exposure resulted in glucose intolerance in the mothers during pregnancy and post-term period, regardless of the exposure dose. This was accompanied by increased visceral adipose tissue mass, dyslipidemia, unchanged pancreatic β-cell mass, and varying insulin responses to glucose in vivo. The number of total newborns and birthweight was not affected by malathion exposure. Adult offspring from both sexes also became glucose-intolerant, regardless of the pesticide dose their dams were exposed to. This alteration could be associated with changes at the epigenomic level, as reduced hepatic mRNA content of DNA methylases and demethylases was found. We demonstrated that periconceptional exposure to malathion with doses aiming to mimic from work environment to indirect contamination predisposes progenitors and offspring rats to glucose intolerance. Thus, we conclude that subchronic exposure to malathion is a risk factor for gestational diabetes and prediabetes later in life.

Maternal training during lactation modifies breast milk fatty acid composition and male offspring glucose homeostasis in rat

The perinatal exposome can modify offspring metabolism and health later in life. Within this concept, maternal exercise during gestation has been reported modifying offspring glucose sensing and homeostasis, while the impact of such exercise during lactation is little-known. We thus aimed at evaluating short- and long-term effects of it on offspring pancreatic function, assuming a link with changes in breast milk composition. Fifteen-week-old primiparous female Wistar rats exercised during lactation at a constant submaximal intensity (TR) or remained sedentary (CT). Male offspring were studied at weaning and at 7 months of age for growth, pancreas weight, glycemia and insulin responses. Milk protein content was determined by the bicinchoninic acid assay (BCA colorimetric method), and lipid content and fatty acid composition by gas chromatography. Mature milk from TR rats contained significantly less saturated (−7 %) and more monounsaturated (+18 %) and polyunsaturated (PUFA +12 %) fatty acids compared to CT rats, with no difference in total lipid and protein concentrations. In offspring from TR vs CT mothers, fasting glycemia was lower, pancreas weight was higher with a lower insulin content (−37 %) at weaning. Such outcomes were correlated with milk PUFA levels and indices of desaturase or elongase activities. These effects were no longer present at 7 months, whereas a more efficient muscle insulin sensitivity was observed. Maternal training during lactation led to a specific milk phenotype that was associated with a short-term impact on glucose homeostasis and pancreatic function of the male offspring.

Effects of alkaloid-rich extracts obtained from Grifola frondosa on gut microbiota and glucose homeostasis in rats.

Grifola frondosa (GF), also known as maitake (a type of mushroom), has been widely used as a food item and it exhibits various health-beneficial hypoglycemic activities. Rats fed with a fat/high-sucrose-based diet were used to determine the hypoglycemic activity of 95% and 55% GF ethanol extracts (labeled as GF95 and GF55, respectively). The activity was determined by monitoring the fasting blood glucose level. Oral glucose tolerance tests were conducted, and the levels of alanine aminotransferase and aspartate aminotransferase were studied to study the hypoglycemic activity. The HPLC-ESI-TOF-MS technique was used to analyze the samples, and the results revealed that alkaloids were present in abundance in GF95 and GF55. It was also observed that GF55 contained some organic acids and GF95 contained extra small amounts of phenoloid. The levels of intestinal microbiota were analyzed, and the results from transcriptome analysis indicated that GF55 reduced the relative abundance of Romboutsia and affected RT-Db1, thereby improving the extent of glucose metabolism achieved. GF95 downregulated the mRNA level of Socs1 by increasing the levels of Oscillibacter, Butyricimonas, Barnesiella, Turicibacter, Methanosphaera, Asaccharobacter, Globicatella, Bifidobacterium, Allobaculum, and Romboutsia. The expression of Pik3rl was upregulated when the levels of Ruminococcus and Saccharibacteria increased. The hypoglycemic activity was induced under these conditions. The obtained data indicated that the efficiency of GF95 to control glucose levels was higher than the efficiency of GF55. This suggested that GF95 can be potentially used to protect against hyperglycemia.

Combination of α-Glycosyl-Isoquercitrin and Soybean Fiber Promotes Quercetin Bioavailability and Glucagon-like Peptide-1 Secretion and Improves Glucose Homeostasis in Rats Fed a High-Fat High-Sucrose Diet.

This study examined the effects of a combination of soybean fiber and α-glycosyl-isoquercitrin (AGIQ) on improving quercetin bioavailability and glucose metabolism in rats fed an obesogenic diet. For 9 weeks, rats were individually fed a control diet, a high-fat high-sucrose (H) diet, H with soybean fiber (HS), or with AGIQ (HQ), or with both (HSQ). Quercetin derivatives in plasma, feces, urine, and cecal content were quantified by high-performance liquid chromatography to assess the bioavailability of quercetin, and meal tolerance tests were performed to assess postprandial glycemia and glucagon-like peptide-1 (GLP-1) responses. The HSQ group had higher plasma quercetin levels than HQ. The postprandial glycemia was attenuated in the HSQ group when compared to the H group. The basal plasma GLP-1 concentrations positively correlated with plasma quercetin derivative concentrations. Hence, the combination of soybean fiber and AGIQ could be beneficial for reducing the risk of glucose intolerance, possibly involving enhanced quercetin bioavailability and GLP-1 secretion.

Leptin Receptors Are Not Required for Roux-en-Y Gastric Bypass Surgery to Normalize Energy and Glucose Homeostasis in Rats.

Sensitization to the adipokine leptin is a promising therapeutic strategy against obesity and its comorbidities and has been proposed to contribute to the lasting metabolic benefits of Roux-en-Y gastric bypass (RYGB) surgery. We formally tested this idea using Zucker fatty fa/fa rats as an established genetic model of obesity, glucose intolerance, and fatty liver due to leptin receptor deficiency. We show that the changes in body weight in these rats following RYGB largely overlaps with that of diet-induced obese Wistar rats with intact leptin receptors. Further, food intake and oral glucose tolerance were normalized in RYGB-treated Zucker fatty fa/fa rats to the levels of lean Zucker fatty fa/+ controls, in association with increased glucagon-like peptide 1 (GLP-1) and insulin release. In contrast, while fatty liver was also normalized in RYGB-treated Zucker fatty fa/fa rats, their circulating levels of the liver enzyme alanine aminotransferase (ALT) remained elevated at the level of obese Zucker fatty fa/fa controls. These findings suggest that the leptin system is not required for the normalization of energy and glucose homeostasis associated with RYGB, but that its potential contribution to the improvements in liver health postoperatively merits further investigation.

Effects of Bidens gardneri Baker leaves aqueous extract in glucose homeostasis of rats

Bidens gardneri Baker, popularly known as “picão-vermelho”, has been used, traditionally, as a medicinal plant for the treatment of Diabetes mellitus. This study aimed to evaluate antidiabetic effect of leaves from B. gardneri aqueous extract (BGAE). We also evaluated in vitro anti-glycation potential. Chemical composition was analyzed based on a colorimetrics and HPLC methods. The oral glucose tolerance test (OGTT), was performed in rats with different doses (30, 100 and 300 mg/kg). Alloxan-induced diabetic and hypercaloric diet-fed rats were treated with 300 mg/kg of BGAE, orally, for 10 days and then 10 weeks, respectively. The activity of intestinal disaccharidases (maltase, sucrase and lactase) and quantification of muscle and liver glycogen content were also evaluated. On chemical analysis, the extract showed high phenolics content and the chromatogram showed 4-O-caffeoylquinic acid as the major component. The extract presented inhibition in the formation of advanced glycation end products (AGEs) and disaccharidases activity. In OGTT the dose of 300 mg/kg significantly decreased the blood glucose. In diabetic animals, BGAE significantly decreased blood glucose levels, preventing weight loss. In addition, in hypercaloric diet-fed rats, the extract prevented hyperglycemia. Our results suggest that, aqueous extract of B. gardneri has a potential for therapeutic intervention of diabetes.

Consumption of lycopene-rich tomatoes improved glucose homeostasis in rats via an increase in leptin levels.

The lycopene content of tomatoes is important because of its effects on vital physiological functions such as improvement of glucose tolerance and non-alcoholic fatty liver disease. To investigate the influence of the lycopene content of tomatoes on glucose tolerance and hepatic lipid content, homogenates of lycopene-rich (LR) or lycopene-free negative control (NC) tomato varieties were administrated to normal rats for 4weeks. At the end of the experiment, an oral glucose tolerance test (OGTT) was performed. Rats were fed once and then dissected. According to the OGTT results, plasma glucose levels in the LR group were 10% and 9% lower at 15min and 30min, respectively, than those in the NC group, whereas plasma insulin levels did not differ between the groups at either time point. Upon dissection, plasma leptin levels in the LR group were higher than those in the NC group, while plasma adiponectin levels did not differ between groups. With the exception of retinol palmitate, no carotenoids were detected in the liver by HPLC analysis. Hepatic retinol palmitate levels and hepatic triacyl glyceride levels did not differ between the groups. We concluded that in normal rats, a lycopene-rich tomato variety improved glucose tolerance via an increase in plasma leptin levels that enhanced insulin sensitivity but did not affect carotenoid accumulation or lipid metabolism.

Refeeding abolishes beneficial effects of severe calorie restriction from birth on adipose tissue and glucose homeostasis of adult rats.

Calorie restriction (CR) is an important intervention for reducing adiposity and improving glucose homeostasis. Recently we found that in rats, a severe calorie restriction (SCR) beginning at birth up to adult age promotes positive effects on cardiometabolic risk factors and heart. The aim of this study was to investigate the effects of this new model of SCR on adipose tissue and glucose homeostasis of rats and to evaluate the effects of refeeding. From birth to 90 d of age, rats were divided into an ad libitum (AL) group, which had free access to food, and a CR50 group, which had food limited to 50% of that consumed by the AL group. From this moment, half of the CR50 animals had free access to food (the refeeding group [CR50-R]), and the other half continued 50% restricted for an additional 90-d period. Food intake was assessed daily and body weight weekly. In the final week of the SCR/refeeding protocol, oral glucose and intraperitoneal insulin tolerance tests were performed. Thereafter, rats were sacrificed and visceral fat was collected and used for histologic and Western blot analysis. Findings from this study revealed that SCR beginning at birth and up to adult life promoted a large decrease in visceral adiposity; improvement in glucose/insulin tolerance; and upregulation of adipose proliferating cell nuclear antigen, sirtuin 1, peroxisome proliferator-activated receptor-γ, and adiponectin. Refeeding abolished all of these effects. SCR from birth to adult age promoted beneficial effects on adipose tissue and glucose homeostasis; whereas refeeding abolished these effects.

A low-protein, high carbohydrate diet induces increase in serum adiponectin and preserves glucose homeostasis in rats.

The aim of this study was investigate the effects of a low-protein, high-carbohydrate (LPHC) diet introduced to rats soon after weaning. The animals were distributed in the following groups: LPHC45: fed an LPHC diet (6%-protein, 74%-carbohydrate) for 45 days; C45: fed a control (C) diet (17%-protein, 63%-carbohydrate) for 45 days; R (Reverse): fed with LPHC for 15 days followed by C diet for 30 days. The LPHC45 group showed alterations in the energetic balance with an increase in brown adipose tissue, and in glucose tolerance, and lower final body weight, muscle mass and total protein in blood when compared with C45 group. The HOMA-IR index was similar between LPHC45 and C45 groups, but this parameter was lower in LPHC45 compared with R groups. Serum adiponectin was higher in LPHC45 group than C45 and R groups. The R group presented higher fed insulin than C45 and LPHC45 and higher T4 compared with C45 group. Total cholesterol in R group was higher when compared with LPHC45 group. Thus, the data show that the change of the diet LPHC for a balanced diet led to different metabolic evolution and suggest that the different response can be due to different levels of adiponectin.

Vitamin E supplementation and caloric restriction promotes regulation of insulin secretion and glycemic homeostasis by different mechanisms in rats.

Vitamin E and caloric restriction have antioxidant effects in mammals. The aim of this study was to evaluate effects of vitamin E supplementation and caloric restriction upon insulin secretion and glucose homeostasis in rats. Male Wistar rats were distributed among the following groups: C, control group fed ad libitum; R, food quantity reduction of 40%; CV, control group supplemented with vitamin E [30 mg·kg-1·day-1]; and RV, food-restricted group supplemented with vitamin E. The experiments ran for 21 days. Glucose tolerance and insulin sensitivity was higher in the CV, R, and RV groups. Insulin secretion stimulated with different glucose concentrations was lower in the R and RV groups, compared with C and CV. In the presence of glucose and secretagogues, insulin secretion was higher in the CV group and was lower in the R and RV groups. An increase in insulin receptor occurred in the fat pad and muscle tissue of groups CV, R, and RV. Levels of hepatic insulin receptor and phospho-Akt protein were higher in groups R and RV, compared with C and CV, while muscle phospho-Akt was increased in the CV group. There was a reduction in hepatic RNA levels of the hepatocyte growth factor gene and insulin degrading enzyme in the R group, and increased levels of insulin degrading enzyme in the CV and RV groups. Thus, vitamin E supplementation and caloric restriction modulate insulin secretion by different mechanisms to maintain glucose homeostasis.

Long-term follow-up of muscle lipid accumulation, mitochondrial activity and oxidative stress and their relationship with impaired glucose homeostasis in high fat high fructose diet-fed rats

Metabolic syndrome components, including obesity, dyslipidemia and impaired glucose homeostasis, become a major public health issue. Muscles play a predominant role in insulin-mediated glucose uptake, and high fat diets may negatively affect muscle function and homeostasis. This work aimed to study the time-course of muscle lipid accumulation, oxidative stress and mitochondrial dysfunction and their association to impaired glucose homeostasis in rats fed an obesogenic diet. Male Wistar rats were fed with a standard or a high fat/high fructose (HFHFr) diet and sacrificed on 4, 8, 12, 16, 20 weeks. Rats fed the HFHFr diet developed mild overweight, increased liver and adipose tissue weights and glucose intolerance. The impaired glucose homeostasis increased gradually with the HFHFr diet to become significant on the 12th and 16th weeks of diet. In parallel, the muscle lipid composition showed an increase in the saturated fatty acids and the monounsaturated fatty acids with a marked decrease in the polyunsaturated fatty acids. The HFHFr diet also increased muscle contents of both diacylglycerols and Ceramides. Surprisingly, HFHFr diet did not induce major muscle mitochondrial dysfunction or oxidative stress. These results indicate that muscle lipid alterations, as well as impaired glucose homeostasis occur as early as the 8th week of HFHFr diet, increase to reach a plateau around the 12th–16th weeks of diet, and then attenuate towards the end of study. At these diet treatment durations, muscle mitochondrial activity and oxidative stress remained unchanged and do not seem to have a major role in the observed impaired glucose homeostasis.

Effect of food azo-dye tartrazine on physiological functions of pancreas and glucose homeostasis

Abstract Background Food industry is extensively using tartrazine however, influence of tartrazine-exposure on pancreas remains to be elucidated. Materials and methods This study was designed to evaluate the effect of tartrazine on pancreas and glucose homeostasis in rats. Albino rats were divided into three groups. Group I was control, group II and III were assigned as low and high doses of tartrazine-exposed groups respectively. Blood samples were collected to estimate the glucose homeostasis and insulin, amylase and lipase activity, and glucose tolerance along with morphology of pancreas. Results The results showed that tartrazine at higher doses, increased blood sugar (230.830±0.940 mg/dL) and insulin (0.395±0.012 ng/mL) levels as compared to that of control. HOMA-IR value of tartrazine-exposed rats was significantly high (1.450±0.090) as compared to that of control. Moreover, the serum levels of amylase and lipase were also increased significantly in tartrazine-exposed rats. Correspondingly, morphology of pancreas was also found to be changed in tartrazine-exposed rats. Conclusion These results demonstrated that tartrazine has a critical influence on glucose homeostasis. This evidently reveals that tartrazine has damaging effects on pancreas and enduring the exposure of tartrazine could possibly result in the disturbance of normal endocrine functioning of pancreas.

Metabolomics reveals that vine tea (Ampelopsis grossedentata) prevents high-fat-diet-induced metabolism disorder by improving glucose homeostasis in rats.

BackgroundVine tea (VT), derived from Ampelopsis grossedentata (Hand.-Mazz.) W.T. Wang, is an alternative tea that has been consumed widely in south China for hundreds of years. It has been shown that drinking VT on a daily basis improves hyperlipidemia and hyperglycemia. However, little is known about the preventive functions of VT for metabolic dysregulation and the potential pathological mechanisms involved. This paper elucidates the preventive effects of VT on the dysregulation of lipid and glucose metabolism using rats maintained on a high-fat-diet (HFD) in an attempt to explain the potential mechanisms involved.MethodsSprague Dawley (SD) rats were divided into five groups: a group given normal rat chow and water (control group); a group given an HFD and water (HFD group); a group given an HFD and Pioglitazone (PIO group), 5 mg /kg; and groups given an HFD and one of two doses of VT: 500 mg/L or 2000 mg/L. After 8 weeks, changes in food intake, tea consumption, body weight, serum and hepatic biochemical parameters were determined. Moreover, liver samples were isolated for pathology histology and liquid chromatography-mass spectrometry (LC-MS)-based metabolomic research.ResultsVT reduced the serum levels of glucose and total cholesterol, decreased glucose area under the curve in the insulin tolerance test and visibly impaired hepatic lipid accumulation. Metabolomics showed that VT treatment modulated the contents of metabolic intermediates linked to glucose metabolism (including gluconeogenesis and glycolysis), the TCA cycle, purine metabolism and amino acid metabolism.ConclusionThe current results demonstrate that VT may prevent metabolic impairments induced by the consumption of an HFD. These effects may be caused by improved energy-related metabolism (including gluconeogenesis, glycolysis and TCA cycle), purine metabolism and amino acid metabolism, and reduced lipid levels in the HFD-fed rats.

A novel free fatty acid receptor 1 (GPR40/FFAR1) agonist, MR1704, enhances glucose-dependent insulin secretion and improves glucose homeostasis in rats.

Activation of G protein‐coupled receptor 40/Free fatty acid receptor 1 (GPR40/FFAR1), which is highly expressed in pancreatic β cells, is considered an important pharmacologic target for the treatment of type 2 diabetes mellitus. The aim of this study was to determine the effect of MR1704, a novel GPR40/FFAR1 agonist, on glucose homeostasis in rats. MR1704 is a highly potent and selective, orally bioavailable agonist with similar in vitro potencies among humans, mice, and rats. Treatment of rat islets with MR1704 increased glucose‐dependent insulin secretion. Augmentation of glucose‐dependent insulin secretion was abolished by adding a GPR40/FFAR1 antagonist. In mouse, insulinoma MIN6 cells, palmitic acid induced the activity of caspase 3/7 after a 72‐h exposure, while pharmacologically active concentrations of MR1704 did not. In an oral glucose tolerance test in normal Sprague‐Dawley rats, orally administered MR1704 (1–10 mg·kg−1) reduced plasma glucose excursion and enhanced insulin secretion, but MR1704 did not induce hypoglycemia, even at 300 mg·kg−1, in fasted Sprague‐Dawley rats. In addition, orally administered MR1704 reduced plasma glucose excursion and enhanced insulin secretion in diabetic Goto‐Kakizaki rats. Oral administration of MR1704 once daily to Goto‐Kakizaki rats reduced their blood glucose levels during a 5‐week treatment period without reducing pancreatic insulin content; as a result, hemoglobin A1C levels significantly decreased. These results suggest that MR1704 improves glucose homeostasis through glucose‐dependent insulin secretion with a low risk of hypoglycemia and pancreatic toxicity. MR1704 shows promise as a new, glucose‐lowering drug to treat type 2 diabetes mellitus.

GTF-231, a Mixture of Gymnemic Acid, Trigonelline and Ferulic Acid Significantly Ameliorates Oxidative Stress in Experimental Type 2 Diabetes in Rats.

According to a report by the United States National Health and Nutrition Examination Survey, nearly 60% of patients with diabetes have more than one complication caused by chronic diabetes. Type 2 diabetes is a multifactorial metabolic disorder that accounts for more than 95% of people with diabetes and usually requires multitargeted therapeutic interventions. It arises due to insufficient insulin secretion or its action or both. Recently, we reported that the oral administration of gymnemic acid, trigonelline and ferulic acid in the ratio of 2:3:1 (GTF-231), a mixture of 3 phytoingredients at a concentration of 300 mg/kg body weight significantly improved the glucose homeostasis in rats with low-dose streptozotocin-induced type 2 diabetes that were fed with high-fat diet. In the present study, an effort was made to evaluate the antioxidant potential of GTF-231 in rats with type 2 diabetes. Type 2 diabetes was induced in experimental rats by administration of low-dose streptozotocin (35 mg/kg body weight) and high-fat diet. The biochemical parameters analyzed included levels of fasting blood glucose, glycated hemoglobin, plasma insulin, homeostatic model assessment-insulin resistance, homeostatic model assessment beta-cell function, advanced glycation end products, advanced oxidation protein products, hydroperoxides, malondialdehyde and enzymatic as well as nonenzymatic antioxidants and proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin 1 beta, interleukin-6, nuclear factor-κB and nitric oxide. Histologic observations were made on the pancreatic tissues. The data obtained showed the significant antioxidant properties of GTF-231, which were further evidenced by the histologic observations made on the pancreatic tissue. The observed antioxidant potential of GTF-231 may account for its significant antidiabetic properties.

Mid‐Term Exposure to Prednisone is Less Detrimental than Short‐Term Dexamethasone on Glucose Homeostasis in Rats

Synthetic glucocorticoids (GCs) are pontent and widely used anti‐inflammatory and immunosuppressant agents. However, prolonged or high‐dose usage of GCs promote several side effects, especially on glucose and lipid metabolism. In spite of the abovementioned factors, there is scanty data on differential impact of distinct synthetic GC on metabolic targets, particularly glycolipidic homeostasis. Thus, this work aimed to assess the metabolic alterations caused by subchronic treatment with prednisone in comparison to acute dexamethasone. For this, 90‐days old Wistar rats were treated with dexamethasone (1 mg/kg/day, i.p., D5 group, n=8) for 5 consecutive days and compared to saline‐treated control rats (C5, n=9). Additionally, 60‐days old rats were treated with prednisone (80 mg/kg/day, orally) for 15 days (P15, n=7) and 30 days (P30, n=12) and compared to their respective controls (C15, n=7 and C30, n=12), which received vehicle solution. D5 rats showed decreased body weight (−12.3%) and lower retroperitoneal fat accumulation (−38%), increased fasting (+12%) and fed (+30%) glycemia, higher insulinemia (+80%), higher free fatty acids (+114%) and hypertriglyceridemia (+339%). Total fat and triglycerides content in the liver were 29% and 52% higher in D5 than in C5 rats, respectively. P15 rats weight gain was 61% lower, with reduction of retroperitoneal fat (−29%) and increased plasma triglyceride levels (+60%), as compared to C15 rats. 30 days treatment promoted similar but deeper effects on the same parameters. In vivo protocols revealed impaired glucose tolerance (oGTT) in D5 and P30 rats. However, P30 rats did not show reduced insulin sensitivity (ipITT, HOMA, TyG), as observed in D5 animals. Ex vivo assessment of glucose‐stimulated insulin secretion showed dysfunctional response in D5 but not P30 rats. In conclusion, our data suggest that mid‐term administration of prednisone promoted lesser metabolic side effects on glucose homeostasis, as compared to short‐term administration of dexamethasone, supporting its preferential use in order to minimize adverse metabolic effects associated to GCs treatment.Support or Funding InformationFAPEMA, UFMA and CAPES