sincalide and Hyperglycemia

Recent studies suggest that the interaction between small intestinal nutrient stimulation and the blood glucose concentration is important in the regulation of gastric motility and appetite. The purpose of this study was to determine whether the effects of cholecystokinin octapeptide (CCK-8) on antropyloric motility and appetite are influenced by changes in the blood glucose concentration within the normal postprandial range. Seven healthy volunteers were studied on 4 separate days. A catheter incorporating a sleeve sensor was positioned across the pylorus, and the blood glucose was stabilized at either 4 mmol/l (2 days) or 8 mmol/l (2 days). After the desired blood glucose had been maintained for 90 min, an intravenous infusion of either CCK-8 (2 ng. kg(-1). min(-1)) or saline (control) was given for 60 min. Thirty minutes after the infusion began, the catheter was removed and subjects drank 400 ml of water with guar gum before being offered a buffet meal. The amount of food consumed (kcal) was quantified. The order of the studies was randomized and single-blinded. There were fewer antral waves at a blood glucose of 8 than at 4 mmol/l during the 90-min period before the infusions (P<0.05) and during the first 30 min of CCK-8 or saline infusion (P = 0.07). CCK-8 suppressed antral waves (P<0.05), stimulated isolated pyloric pressure waves (IPPWs) (P<0.01), and increased basal pyloric pressure (P<0.005) compared with control. During administration of CCK-8, basal pyloric pressure (P<0.01), but not the number of IPPWs, was greater at a blood glucose of 8 mmol/l than at 4 mmol/l. CCK-8 suppressed the energy intake at the buffet meal (P<0.01), with no significant difference between the two blood glucose concentrations. We conclude that the acute effect of exogenous CCK-8 on basal pyloric pressure, but not appetite, is modulated by physiological changes in the blood glucose concentration.

Topics: Adult; Appetite; Blood Glucose; Eating; Female; Gastrointestinal Motility; Humans; Hunger; Hyperglycemia; Male; Nausea; Pressure; Pyloric Antrum; Pylorus; Satiety Response; Sincalide; Single-Blind Method

Cholecystokinin (CCK) is a hormone that has important physiological effects on energy balance. This study has used a stable CCK(1) receptor agonist, (pGlu-Gln)-CCK-8, to evaluate the metabolic effects of prolonged administration in normal mice. Twice-daily injection of (pGlu-Gln)-CCK-8 for 28 days resulted in significantly lowered body weights (P<0.05) on days 24 and 28, which was associated with decreased accumulated calorie intake (P<0.01) from day 12 onward. Nonfasting plasma glucose was significantly reduced (P<0.05) on day 28, while plasma insulin concentrations were increased (P<0.05). After 28 days, glucose tolerance and glucose-mediated insulin secretion were not significantly different in (pGlu-Gln)-CCK-8-treated mice. However, following a 15-min refeeding period in 18-h fasted mice, glucose levels were significantly (P<0.05) decreased by (pGlu-Gln)-CCK-8 despite similar food intake and nutrient-induced insulin levels. Insulin sensitivity in (pGlu-Gln)-CCK-8-treated mice was significantly (P<0.01) improved compared with controls. Accumulation of triacylglycerol in liver was reduced (P<0.01) but there were no differences in circulating cholesterol and triacylglycerol concentrations, as well as triacylglycerol content of pancreatic, muscle, and adipose tissue in (pGlu-Gln)-CCK-8 mice. These data highlight the beneficial metabolic effects of prolonged (pGlu-Gln)-CCK-8 administration and confirm a lack of detrimental effects.

Topics: Animals; Anti-Obesity Agents; Blood Glucose; Energy Intake; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Secreting Cells; Liver; Male; Mice; Postprandial Period; Receptor, Cholecystokinin A; Signal Transduction; Sincalide; Time Factors; Triglycerides; Weight Gain

The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) and cholecystokinin (CCK) are gastrointestinal peptides with important physiological effects. However, rapid enzymatic degradation results in short-lived biological actions.. This study has examined metabolic actions of exendin-4, GIP[mPEG] and a novel CCK-8 analogue, (pGlu-Gln)-CCK-8 as enzymatically stable forms of GLP-1, GIP and CCK, respectively.. All peptides significantly (p < 0.01-p < 0.001) stimulated insulin secretion from BRIN BD11 cells, and acute in vivo experiments confirmed prominent antihyperglycaemic and insulinotropic responses to GLP-1 or GIP receptor activation in normal mice. Twice daily injection of (pGlu-Gln)-CCK-8 alone and in combination with exendin-4 or GIP[mPEG] in high fat-fed mice significantly decreased accumulated food intake (p < 0.05-p < 0.01), body weight gain (p < 0.05-p < 0.01) and improved (p < 0.05) insulin sensitivity in high fat-fed mice. However, there was no evidence for superior effects compared to (pGlu-Gln)-CCK-8 alone. Combined treatment of (pGlu-Gln)-CCK-8 and exendin-4 resulted in significantly (p < 0.05) lowered circulating glucose levels and improved (p < 0.05) intraperitoneal glucose tolerance. These effects were superior to either treatment regime alone but not associated with altered insulin concentrations. A single injection of (pGlu-Gln)-CCK-8, or combined with exendin-4, significantly (p < 0.05) lowered blood glucose levels 24 h post injection in untreated high fat-fed mice.. This study highlights the potential of (pGlu-Gln)-CCK-8 alone and in combination with incretin hormones for the treatment of type 2 diabetes.

Topics: Animals; Anti-Obesity Agents; Appetite Regulation; Cell Line; Diabetes Mellitus, Type 2; Diet, High-Fat; Drug Therapy, Combination; Exenatide; Gastric Inhibitory Polypeptide; Hyperglycemia; Hypoglycemic Agents; Incretins; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Mice; Mice, Inbred Strains; Obesity; Peptides; Rats; Sincalide; Time Factors; Venoms

Topics: Animals; Cell Division; Cholecystokinin; Colon; Gastric Inhibitory Polypeptide; Humans; Hyperglycemia; Ileum; Insulin; Insulin Secretion; Islets of Langerhans; Pancreas; Rats; Sincalide

Topics: Animals; Blood Glucose; Cholecystokinin; Glucose; Hyperglycemia; Injections, Intraventricular; Rats; Sincalide; Time Factors

Intracerebroventricular administration of cholecystokinin-octapeptide (CCK-8) in unanesthetized, unrestrained rats suppressed stress-induced eating and produced hyperglycemia. Prior adrenalectomy markedly reduced the hyperglycemia effect of intraventricular CCK-8 and also decreased the suppressive effect of CCK-8 on stress-induced eating. Our data are compatible with the anorectic effect of CCK-8 being secondary to the hyperglycemia it produces.

Topics: Adrenalectomy; Animals; Cholecystokinin; Eating; Hyperglycemia; Injections, Intraventricular; Male; Peptide Fragments; Rats; Rats, Inbred Strains; Sincalide; Stress, Physiological