Plasma Glucose Responses Research Articles

Effects of Moderate- and Intermittent Low-Intensity Exercise on Postprandial Lipemia

The elevation of postprandial plasma triglycerides (PPTG) in the blood is an independent risk factor for atherosclerosis. Although acute exercise typically attenuates PPTG, the effect of exercise intensity on PPTG is less well established, particularly in well-controlled conditions for physical activities and diet. We sought to determine the efficacy of exercise at 65% V˙O2max with an extended sitting time and isoenergetic intermittent walking exercise at a self-selected walking speed (approximately 25% V˙O2max) on PPTG compared with that of a sitting control condition. In a randomized crossover design, nine healthy young men completed three trials with a >1-wk interval between trials. After 2 d of activity and diet normalization, participants performed prolonged sitting nonexercise control (CON), prolonged sitting with subsequent 1-h running at 65% V˙O2max (MOD), or isoenergetic intermittent walking at approximately 25% V˙O2max (LOW) on day 3. This was followed on day 4 by a 6-h high-fat tolerance test. MOD and LOW reduced incremental triglyceride (TG) area under the curve (TG AUCI) compared with that in CON by 33.6% (P < 0.005) and 19.8% (P < 0.05), respectively. MOD also reduced TG AUCI compared with that in LOW by 17.2% (P < 0.03). The reduced TG AUCI in MOD was accompanied by reduced plasma glucose response and enhanced fat oxidation compared with those in LOW and CON (for all, P < 0.05), respectively. Both MOD and LOW were effective in reducing PPTG compared with CON. However, MOD was more effective in reducing PPTG compared with LOW.

Determining pancreatic β-cell compensation for changing insulin sensitivity using an oral glucose tolerance test.

Plasma glucose, insulin, and C-peptide responses during an OGTT are informative for both research and clinical practice in type 2 diabetes. The aim of this study was to use such information to determine insulin sensitivity and insulin secretion so as to calculate an oral glucose disposition index (DI(OGTT)) that is a measure of pancreatic β-cell insulin secretory compensation for changing insulin sensitivity. We conducted an observational study of n = 187 subjects, representing the entire glucose tolerance continuum from normal glucose tolerance to type 2 diabetes. OGTT-derived insulin sensitivity (S(I OGTT)) was calculated using a novel multiple-regression model derived from insulin sensitivity measured by hyperinsulinemic euglycemic clamp as the independent variable. We also validated the novel S(I OGTT) in n = 40 subjects from an independent data set. Plasma C-peptide responses during OGTT were used to determine oral glucose-stimulated insulin secretion (GSIS(OGTT)), and DI(OGTT) was calculated as the product of S(I OGTT) and GSIS(OGTT). Our novel S(I OGTT) showed high agreement with clamp-derived insulin sensitivity (typical error = +3.6%; r = 0.69, P < 0.0001) and that insulin sensitivity was lowest in subjects with impaired glucose tolerance and type 2 diabetes. GSIS(OGTT) demonstrated a significant inverse relationship with S(I OGTT). GSIS(OGTT) was lowest in normal glucose-tolerant subjects and greatest in those with impaired glucose tolerance. DI(OGTT) was sequentially lower with advancing glucose intolerance. We hereby derive and validate a novel OGTT-derived measurement of insulin sensitivity across the entire glucose tolerance continuum and demonstrate that β-cell compensation for changing insulin sensitivity can be readily calculated from clinical variables collected during OGTT.

The immediate effects of a single bout of aerobic exercise on oral glucose tolerance across the glucose tolerance continuum

We investigated glucose tolerance and postprandial glucose fluxes immediately after a single bout of aerobic exercise in subjects representing the entire glucose tolerance continuum. Twenty‐four men with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), or type 2 diabetes (T2D; age: 56 ± 1 years; body mass index: 27.8 ± 0.7 kg/m2, P > 0.05) underwent a 180‐min oral glucose tolerance test (OGTT) combined with constant intravenous infusion of [6,6‐2H2]glucose and ingestion of [U‐13C]glucose, following 1 h of exercise (50% of peak aerobic power) or rest. In both trials, plasma glucose concentrations and kinetics, insulin, C‐peptide, and glucagon were measured. Rates (mg kg−1 min−1) of glucose appearance from endogenous (RaEndo) and exogenous (oral glucose; RaOGTT) sources, and glucose disappearance (Rd) were determined. We found that exercise increased RaEndo, RaOGTT, and Rd (all P < 0.0001) in all groups with a tendency for a greater (~20%) peak RaOGTT value in NGT subjects when compared to IGT and T2D subjects. Accordingly, following exercise, the plasma glucose concentration during the OGTT was increased in NGT subjects (P < 0.05), while unchanged in subjects with IGT and T2D. In conclusion, while a single bout of moderate‐intensity exercise increased the postprandial glucose response in NGT subjects, glucose tolerance following exercise was preserved in the two hyperglycemic groups. Thus, postprandial plasma glucose responses immediately following exercise are dependent on the underlying degree of glycemic control.

High saturated fatty acid intake induces insulin secretion by elevating gastric inhibitory polypeptide levels in healthy individuals

Insulin resistance is central to the etiology of the metabolic syndrome cluster of diseases. Evidence suggests that a high-fat diet is associated with insulin resistance, which may be modulated by dietary fatty acid composition. We hypothesized that high saturated fatty acid intake increases insulin and gastric inhibitory polypeptide (GIP) secretion. To clarify the effect of ingested fatty acid composition on glucose levels, we conducted an intervention study to investigate the insulin and plasma GIP responses in 11 healthy women, including a dietary control. Subjects were provided daily control meals (F-20; saturated fatty acids/monounsaturated fatty acids/polyunsaturated fatty acids [S/M/P] ratio, 3:4:3) with 20 energy (E) % fat, followed by 2 isoenergetic experimental meals for 7 days each. These meals comprised 60 E% carbohydrate, 15 E% protein, and 30 E% fat (FB-30; high saturated fatty acid meal; S/M/P, 5:4:1; F-30: reduced saturated fatty acid meal; S/M/P, 3:4:3). On the second day of the F-20 and the last day of F-30 and FB-30, blood samples were taken before and 30, 60, and 120 minutes after a meal tolerance test. The plasma glucose responses did not differ between F-20 and FB-30 or F-30. However, insulin levels were higher after the FB-30 than after the F-20 (P < .01). The GIP response after the FB-30 was higher than that after the F-30 (P < .05). In addition, the difference in the incremental GIP between FB-30 and F-30 correlated significantly and positively with that of the insulin. These results suggest that a high saturated fatty acid content stimulates postprandial insulin release via increased GIP secretion.

Interaction of ingested leucine with glycine on insulin and glucose concentrations.

The majority of individual amino acids increase insulin and attenuate the plasma glucose response when ingested with glucose. Objective. To determine whether ingestion of two amino acids simultaneously, with glucose, would result in an additive effect. Leucine (Leu) and glycine (Gly) were chosen because they were two of the most potent glucose-lowering amino acids when given individually. Materials and Methods. Nine subjects received test items on four separate days. The first was a water control, then 25 g glucose, or Leu + Gly (1 mmol/kg fat-free mass each) ±25 g glucose, in random order. Glucose, insulin, and glucagon were measured frequently for 2.5 hours. Net areas were calculated. Results. The glucose area response decreased by 66%. The insulin area response increased by 24% after ingestion of Leu + Gly + glucose compared to ingestion of glucose alone. The decrease in glucose response was not additive; the increase in insulin response was far less than additive when compared to previously published individual amino acid results. The glucagon concentration remained unchanged. Conclusion. There is an interaction between Leu and Gly that results in a markedly attenuated glucose response. This occurred with a very modest increase in insulin response. Changes in glucagon response could not explain the results. The mechanism is unknown.

ORIGINAL RESEARCH: Chronic Hypoxia Causes Disorder of Glucose Metabolism and a Specific Type of Diabetes

Objective: The purpose of this study was to show the existence of a specific hypoxic diabetes and investigate the effect of prolonged hypoxia on insulin. Research Design and Methods: 101 patients diagnosed with hypoxic chronic obstructive pulmonary disease in its different stages participated in this study. Family and personal histories as well as other causes of diabetes were excluded. Blood glucose and serum insulin response to an oral glucose load were checked during fasting, 30, 60, 120, and, 180 minutes. Plasma glucagon, piruvato, and thyroid hormones were analyzed. Pulmonary function testing was performed. Results: Impaired glucose tolerance in COPD patients were significantly higher than normal control (p < 0.001). The plasma glucose and serum insulin response during oral glucose tolerance test corresponded to a diabetic profile with pronounced hyperinsulinism (p < 0.01). Conclusion: Our results showed that a specific hypoxic type of diabetes occurs under long-term hypoxic condition, affecting insulin synthesis and secretion. Keywords: Long-term hypoxia, irreversible, pathways, glucose metabolism, hyperinsulinism, autocontrol, specific type. Read more →

Activation of the gut calcium-sensing receptor by peptide agonists reduces rapid elevation of plasma glucose in response to oral glucose load in rats.

The calcium-sensing receptor (CaSR) is expressed in various tissues, including the gastrointestinal tract. To investigate the role of gut CaSR on glycemic control, we examined whether single oral administration of CaSR agonist peptides affected the glycemic response in rats. Glucose tolerance tests were performed under oral or duodenal administration of various CaSR agonist peptides (γGlu-Cys, protamine, and poly-d-lysine hydrobromide) in conscious rats. Involvement of CaSR was determined by using a CaSR antagonist. Signaling pathways underlying CaSR agonist-modified glycemia were investigated using gut hormone receptor antagonists. The gastric emptying rate after the administration of CaSR agonist peptides was measured by the phenol red recovery method. Oral and duodenal administration of CaSR agonist peptides attenuated glycemic responses under the oral glucose tolerance test, but the administration of casein did not. The promotive effect on glucose tolerance was weakened by luminal pretreatment with a CaSR antagonist. Treatment with a 5-HT3 receptor antagonist partially diminished the glucose-lowering effect of peptides. Furthermore, the gastric emptying rate was decreased by duodenal administration of CaSR agonist peptides. These results demonstrate that activation of the gut CaSR by peptide agonists promotes glucose tolerance in conscious rats. 5-HT3 receptor and the delayed gastric emptying rate appear to be involved in the glucose-lowering effect of CaSR agonist peptides. Thus, activation of gut CaSR by dietary peptides reduces glycemic responses so that gut CaSR may be a potential target for the improvement of postprandial glycemia.

Postprandial plasma glucose response and gastrointestinal symptom severity in patients with diabetic gastroparesis.

Gastroparesis is a well-known diabetic complication. The pathogenesis is not fully understood. However, it is important to early diagnose these patients. This study evaluated the plasma glucose response after a test meal, and gastrointestinal (GI) symptom severity in patients with clinical suspicion of diabetic gastroparesis, and assessed its usefulness to predict gastroparesis. In all, 83 subjects with insulin-treated diabetes mellitus (DM) type 1 and 2 were included; 53 subjects had gastroparesis and 30 had normal gastric emptying determined by gastric scintigraphy. GI symptom severity during the preceding 2 weeks was evaluated with a validated questionnaire. The test meal consisted of 100 g meat, 40 g pasta, 150 g carrot, and 5 g oil. The subjects ingested the meal under fasting conditions, and plasma glucose was followed during 180 minutes. Patients with gastroparesis demonstrated a blunted plasma glucose response after a test meal versus patients with normal gastric emptying (P < .005), reflected by lower maximum increase in plasma glucose response and incremental area under the curve of the plasma glucose, but a similar time to the maximum plasma glucose level. All GI symptoms were more severe in patients with gastroparesis. GI symptom severity had the best discriminative value to identify patients with gastroparesis with an area under the receiver operating curve of 0.83 (optimal cutoff: sensitivity 87%, specificity 80%). Patients with diabetic gastroparesis have a blunted postprandial plasma glucose response. Combining this information with the presence of GI symptoms can help clinicians identify diabetic patients with gastroparesis.

More symptoms but similar blood glucose curve after oral carbohydrate provocation in patients with a history of hypoglycemia-like symptoms compared to asymptomatic patients after Roux-en-Y gastric bypass

BackgroundLaparoscopic Roux-en-Y gastric bypass (LRYGB) is an effective treatment for obesity through altering several physiologic mechanisms. Some patients experience symptoms suggestive of hypglycemia after LRYGB, but whether these symptoms always are associated with low blood glucose are unclear. The objective of this study was to investigate the correlation between symptoms suggestive of hypglycemia, plasma glucose levels and gut hormones involved in glycemic control. MethodsEight LRYGB patients with hypglycemia-like symptoms (SY) and 8 patients with no hypglycemia-like symptoms (ASY) ingested a liquid carbohydrate meal. Insulin, plasma-glucose, glucagon-like peptide 1 (GLP-1) and glucagon were measured intermittently 180 minutes postprandially. In addition, pulse rate, blood pressure and symptoms were assessed. ResultsPlasma glucose at 120 min was lower in the ASY mean (95% CI) 2.4 (1.6,3.3) mmol/L (43.2 mg/dL) compared to the SY group 3.0 (3.1,4.6) mmol/L (54.6 mg/dL), (P = .050). The ASY group had larger reduction in plasma glucose than the SY group from pre- to 120 min postmeal -2.2 (-2.8,-1.7) mmol/L (-39.6 mg/dL) versus -1.1 (-1.7,-0.4) mmol/L (-19.8 mg/dL), (P = .011). The concentrations of insulin, GLP-1 and glucagon did not differ significantly between groups. Blood pressure was similar between groups, but the AUC for pulse rate was higher in the SY than ASY group 13009 (11148,14870) versus 11569 (10837,12300) beats/180 minutes, (P = .038). The SY group reported more symptoms than the ASY group, AUC for Sigstad scale 60 to 180 minutes was 970 (-274,1667) for SY versus 170 for ASY (-39,379), (P = .028). ConclusionPatients with a history of symptoms suggestive of hypglycemia after LRYGB neither demonstrated lower plasma glucose nor greater insulin response compared to asymptomatic patients in response to a liquid carbohydrate meal, but perceived more symptoms.

Carbohydrate‐rich snacks influence plasma glucose, insulin and ghrelin responses in overweight adults (1039.5)

The effects of a whole food (dried plums; DP) or refined (low‐fat muffins; LFM) snack on satiety and insulin responses following consumption were assessed before and after a snack intervention trial. Forty overweight men and women (age: 36.5 + 11.4, BMI: 32.8 + 7.1 kg/m2) were randomly assigned to consume isocaloric, macronutrient‐matched 100 kcal snacks twice per day of DP or LFM for 8‐weeks. At baseline and 8 weeks, fasted subjects consumed 238 kcal of their randomly assigned food, and blood samples were collected at baseline, 15, 30, 45, 60, 90, and 120 min following intake. Insulin was lower (p蠄0.05) and an earlier peak was observed in DP versus LFM at baseline and 8 weeks. Both groups exhibited lower plasma glucose during the acute response testing after 8 weeks, but glucose peaked earlier in DP than LFM. There were no significant differences in ghrelin concentration over time in either group. These results support the concept that consuming a whole food snack such as dried plums enhances insulin sensitivity as compared to an isocaloric refined snack food, as evidenced by lower insulin concentrations and an earlier peak in insulin and glucose in DP compared to LFM.Grant Funding Source: Supported by the California Dried Plum Board

Acute effects of higher protein, sausage and egg‐based convenience breakfast meals on postprandial glucose homeostasis in healthy, premenopausal women (381.6)

Purpose: To examine the acute effects of commercially‐prepared breakfast meals, varying in protein and carbohydrate content, on plasma glucose (PG) and plasma insulin (PI) responses. Methods: Using a randomized, crossover design, 34 healthy women (age 32 ± 2 y; BMI 24.8 ± 0.5 kg/m2) consumed, on separate days, ~290 kcal breakfasts which were higher protein sausage and egg‐based meals containing 30 g protein (HP‐30) or 39 g protein (HP‐39) or lower protein pancake‐based breakfast meal containing 3 g protein (LP). Pre and post‐breakfast PG and PI concentrations were assessed every 30 min for 240 min; 4h net incremental area under the curve (niAUC) was determined. Results: PG niAUC was not different between meals (HP‐30: ‐140 ± 268; HP‐39: ‐267 ± 219; LP: ‐413 ± 254 mg/dL*240 min; NS). However, post‐breakfast peak PG was 10 ± 1% lower following HP‐30 and 14 ± 1% lower following HP‐39 vs. LP (both, p&lt;0.05). HP‐39 had a 4 ± 1% lower peak PG vs. HP‐30 (p&lt;0.05). PI niAUC was lower following HP‐30 (1067 ± 120) and HP‐39 (952 ± 138) vs. LP (1585 ± 167 µU/mL *240 min; both, p&lt;0.05) with no differences between HP meals. Peak PI was 45 ± 2% lower following HP‐30 and 56 ±2% lower following HP‐39 vs. LP (both, p&lt;0.05). HP‐39 had a 20 ± 2% lower peak PI vs. HP‐30 (p&lt;0.05). Conclusions: Higher protein, sausage and egg convenience meals providing 30 g or 39 g protein improve postprandial glucose homeostasis vs. a lower protein breakfast with greater benefits observed with the 39 g protein breakfast.Grant Funding Source: Supported by Hillshire Brands

Palmitic acid in the sn-2 position decreases glucose-dependent insulinotropic polypeptide secretion in healthy adults

Dietary triacylglycerols (TAGs) containing palmitic acid in the sn-2 position might impair insulin release and increase plasma glucose. We tested this hypothesis by comparing postprandial responses to fats with varying proportions of palmitic acid in the sn-2 position. Using a crossover-designed randomized controlled trial in healthy men (n=25) and women (n=25), we compared four meals on postprandial changes in glucose (primary outcome), insulin, C-peptide, glucose, glucose-dependent insulinotropic polypeptide (GIP) and polypeptide YY (PYY) concentrations. The meals provided 14 g protein, 85 g carbohydrate and 50 g test fat, supplied as high oleic sunflower (HOS) oil (control), palm olein (PO), interesterified palm olein (IPO) and lard containing 0.6, 9.2, 39.1 and 70.5 mol% palmitic acid at sn-2, respectively. No differences in plasma glucose, insulin and C-peptide response between meals were found. GIP release was lower (P<0.001) for IPO and lard compared with HOS and PO meals; the maximal increments (geometric mean and 95% confidence interval) for HOS, PO, IPO and lard were 515 (468, 569), 492 (448, 540), 398 (350, 452) and 395 (364, 429) ng/l, respectively. There was a trend for the postprandial increase in PYY to be lower in women on the IPO and lard meals than those on the HOS and PO meals. Dietary TAGs with an increased proportion of palmitic acid in the sn-2 position do not have acute adverse effects on the insulin and glucose response to meals in healthy men and women, but they decrease GIP release.

Protein Co-Ingestion Strongly Increases Postprandial Insulin Secretion in Type 2 Diabetes Patients

The capacity of nutritional protein to induce endogenous insulin secretion has been well established. However, it is not known whether such a response is applicable in a diverse population of type 2 diabetes patients. The aim of the present study was to assess the impact of co-ingesting either intact or hydrolyzed protein with carbohydrate on postprandial plasma insulin and glucose responses in type 2 diabetes patients. Sixty longstanding, male, type 2 diabetes patients participated in a study in which we determined postprandial plasma insulin and glucose responses after ingesting a single bolus of carbohydrate (0.7 g/kg: CHO) with or without an intact protein (0.3 g/kg: PRO) or its hydrolysate (0.3 g/kg: PROh). Results showed that protein co-ingestion strongly increased postprandial insulin release, with the insulin response +99 ± 41 and +110 ± 10% greater in the CHO+PRO and CHO+PROh experiments when compared with the CHO experiment. The insulinotropic properties of protein co-ingestion were evident in nearly all patients, with 58 out of 60 patients responding >10% when compared with the insulin response following carbohydrate ingestion only (CHO). The concomitant plasma glucose responses were 22 ± 32 and 23 ± 36% lower in the CHO+PRO and CHO+PROh experiments, respectively. We conclude that protein co-ingestion represents an effective dietary strategy to strongly augment postprandial insulin release and attenuate the postprandial rise in glucose concentration in type 2 diabetes patients.

Grain sorghum muffin reduces glucose and insulin responses in men

Diabetes and obesity have sparked interest in identifying healthy, dietary carbohydrates as functional ingredients for controlling blood glucose and insulin levels. Grain sorghum has been known to be a slowly digestible cereal; however, research is limited on its health effects in humans. The objectives of this study were to measure the contents of functional starch fractions, SDS (slowly-digestible starch) and RS (resistant starch), and to investigate the effects of grain sorghum on postprandial plasma glucose and insulin levels in 10 healthy men. A whole-wheat flour muffin (control) was compared with the grain sorghum muffin with both muffins containing 50 g of total starch. Using a randomized-crossover design, male subjects consumed treatments within a one-week washout period, and glucose and insulin levels were observed at 15 minutes before and 0, 15, 30, 45, 60, 75, 90, 120, 180 minutes after consumption. The mean glucose responses reduced after consuming grain sorghum, particularly at 45-120 minute intervals, and mean insulin responses reduced at 15-90 minute intervals compared to control (P < 0.05). The mean incremental area under the curve (iAUC) was significantly lowered for plasma glucose responses about an average of 35% from 3863 ± 443 to 2871 ± 163 mg (∼3 h) dL(-1) (P < 0.05). Insulin responses also reduced significantly from 3029 ± 965 μU (∼3 h) L(-1) for wheat to 1357 ± 204 with sorghum (P < 0.05). Results suggest that grain sorghum is a good functional ingredient to assist in managing glucose and insulin levels in healthy individuals.

Time-of-day of meals modifies plasma glucose and insulin response in overweight males

Introduction: Epidemiological data suggest a distinct role of the time-of-day of food intake on metabolism and weight-loss. However, the impact of timed macronutrient composition in overweight (OW) subjects is even less clear.

The Effect of Moderate Glycemic Energy Bar Consumption on Blood Glucose and Mood in Dancers

Ingesting quality carbohydrates has been shown to be essential for dancers. Given that most dance classes take place in the morning, it has been recommended that dancers eat a well-balanced breakfast containing carbohydrates, fats, and protein as a means of fuelling this activity. The aim of this study was to determine the effect of a moderate glycemic index energy (MGI) bar or a fasting condition on dancers' blood glucose levels and perceived pleasure-displeasure response during the first dance class of the day. In a randomized counterbalanced design, 10 female preprofessional dance students took their regular scheduled contemporary dance class, on four separate occasions. On each occasion, they consumed either a commercially prepared carbohydrate (CHO)-dense energy bar (47.3 g CHO) or water (FAST). Plasma glucose responses and pleasure-displeasure affect were measured before and at two time points during the class. Dancers who consumed the MGI bar had significantly greater peak blood glucose levels at all time points than those who fasted (p<0.05). Regarding affective state measures, participants who had breakfast had significantly greater pleasure scores than those who only ingested water(p<0.05). In conclusion, results suggest that CHO with an MGI value positively impacts blood glucose concentrations during a dance class. Further, we conclude that skipping breakfast can have an unfavorable effect on the pleasure-displeasure state of dancers. These findings highlight the impact of breakfast on how one feels, as well as the physiological and metabolic benefits of CHO as an exogenous energy source in dancers.

Effects of consumption of main and side dishes with white rice on postprandial glucose, insulin, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 responses in healthy Japanese men

The co-ingestion of protein, fat and fibre with carbohydrate reportedly affects postprandial glucose, insulin and incretin (glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1)) responses. However, the effects of combination dishes with carbohydrate-rich foods at typically eaten amounts remain unclear. The objective of the present study was to evaluate the effects of consuming recommended amounts of side dishes with boiled white rice in the same meal on postprandial plasma glucose, insulin and incretin hormone responses. A total of nine healthy male volunteers consumed four different meals in a random order on separate days. The test meals were as follows: S, white rice; SM, addition of protein-rich main dishes to the S meal; SMF, addition of a fat-rich food item to the SM meal; SMFV, addition of vegetables to the SMF meal. Plasma glucose, GIP and GLP-1 and serum insulin concentrations were determined during a 3h period after consumption of these meals. Postprandial glucose responses were lower after SMFV meal consumption than after consumption of the other meals. The incremental AUC for GIP (0-180min) were largest after consumption of the SMF and SMFV meals, followed by that after SM meal consumption, and was smallest after S meal consumption (P<0·05). Furthermore, we found GIP concentrations to be dose dependently increased by the fat content of meals of ordinary size, despite the amount of additional fat being small. In conclusion, the combination of recommended amounts of main and vegetable side dishes with boiled white rice is beneficial for lowering postprandial glucose concentrations, with an increased incretin response, when compared with white rice alone.

Relationship between Glucose and Pancreatic Hormones during the Embryonic and Postnatal Phase in Chickens

Insulin plays a vital role in the regulation of glucose levels in the bloodstream. Chickens have similar circulating insulin concentrations compared to mammals but still maintain high plasma glucose levels. This phenomenon may be a consequence of the development of insulin resistance early in posthatch life, which may be the result of pertubations in the insulin signalling cascade. In addition, our study demonstrates that the response of plasma glucose and the hepatic glucose transporter 2 mRNA to insulin in broiler chicks during the perinatal period is age-dependent. This review addresses the relationship between glucose and pancreatic hormones in embryonic and posthatch stages in the life cycle of the domestic chicken.

Trigonella foenum-graecum seeds lowers postprandial blood glucose in overweight and obese individuals.

This study determined the effects of fenugreek on postprandial plasma glucose (PPG) and satiety among overweight and obese individuals. Fourteen subjects were studied in the morning after overnight fasts on four separate occasions. Glycaemic responses elicited by 50 g carbohydrate portions of white bread and jam with or without 5.5 g of fenugreek and fried rice with or without 5.5 g fenugreek were determined over 2 h. The primary endpoint was the incremental area under the plasma glucose response curve (IAUC). Adding fenugreek to both foods significantly reduced the IAUC compared to the food alone: white bread and jam, 180 ± 22 versus 271 ± 23 mmol × min/L (P = 0.001); fried rice, 176 ± 20 versus 249 ± 25 mmol × min/L (P = 0.001). Fenugreek also significantly reduced the area under the satiety curve for white bread with jam (134 ± 27 versus 232 ± 33 mm × hr, P = 0.01) and fried rice (280 ± 37 versus 379 ± 36 mm × hr, P = 0.01). It is concluded that fenugreek significantly decreased the PPG response and increased satiety among overweight and obese individuals.

Social stress modulates the cortisol response to an acute stressor in rainbow trout (Oncorhynchus mykiss)

In rainbow trout (Oncorhynchus mykiss) of subordinate social status, circulating cortisol concentrations were elevated under resting conditions but the plasma cortisol and glucose responses to an acute stressor (confinement in a net) were attenuated relative to those of dominant trout. An in vitro head kidney preparation, and analysis of the expression of key genes in the stress axis prior to and following confinement in a net were then used to examine the mechanisms underlying suppression of the acute cortisol stress response in trout experiencing chronic social stress. With porcine adrenocorticotropic hormone (ACTH) as the secretagogue, ACTH-stimulated cortisol production was significantly lower for head kidney preparations from subordinate trout than for those from dominant trout. Dominant and subordinate fish did not, however, differ in the relative mRNA abundance of melanocortin-2 receptor (MC2R), steroidogenic acute regulatory protein (StAR) or cytochrome P450 side chain cleavage enzyme (P450scc) within the head kidney, although the relative mRNA abundance of these genes was significantly higher in both dominant and subordinate fish than in sham trout (trout that did not experience social interactions but were otherwise treated identically to the dominant and subordinate fish). The relative mRNA abundance of all three genes was significantly higher in trout exposed to an acute net stressor than under control conditions. Upstream of cortisol production in the stress axis, plasma ACTH concentrations were not affected by social stress, nor was the relative mRNA abundance of the binding protein for corticotropin releasing factor (CRF-BP). The relative mRNA abundance of CRF in the pre-optic area of subordinate fish was significantly higher than that of dominant or sham fish 1h after exposure to the stressor. Collectively, the results indicate that chronic social stress modulates cortisol production at the level of the interrenal cells, resulting in an attenuated cortisol response to an acute stressor.