Endocrine Abstracts

The endocrine cells of the gastrointestinal system are scattered amongst the mucosal cells and respond to luminal influences via projecting microvilli. They also respond to a rich neural supply through the submucous plexus. These two influences, luminal nutriments and local innervation, compete with control by circulating hormones and also nutriment concentrations. The gut endocrine cells are widely scattered down the mucosa (diffuse endocrine system) and their response is pro...

Background: Increased circulating bile acids may contribute to improved glucose control and augmented secretion of the gut hormones peptide tyrosine tyrosine (PYY) and glucagon-like peptide-1 (GLP-1) observed post-prandially in patients following bariatric surgery. Oral bile acids could represent a non-surgical means of improving glucose tolerance after a meal.Aim: To investigate the effects of a single oral dose of ursodeoxycholic acid (UDCA) and chenod...

Ingested protein has a greater satiating effect than other macronutrients. The underlying mechanism is unknown, but it has been shown that protein induces greater increases in anorectic gut hormone levels than carbohydrate or fat. It was hypothesised that these effects could be mediated by specific amino acids comprising the protein. We therefore examined the effects of specific amino acids on food intake and gut hormone release. Fasted male Wistar rats received an oral gavage...

The preproglucagon derived peptides glucagon, glucagon-like peptide-1 (GLP-1) and oxyntomodulin are all known to inhibit appetite and have been previously shown to activate the nucleus tractus solitarius (NTS) in the brainstem. The NTS is involved in the processing of signals transmitted from the periphery to the brain via the vagus nerve. The anorectic effects of peripherally administered glucagon and GLP-1 have been shown to be diminished or ablated by subdiaphragmatic vagot...

PYY is secreted postprandially from the endocrine L-cells of the gastrointestinal tract. PYY3–36, the major circulating form of PYY, reduces food intake in humans and rodents via high affinity binding to the auto-inhibitory NPY receptor, Y2R, within the hypothalamic arcuate nucleus.Aims: To investigate (1) the effects of length of fast on the anorexigenic actions of PYY3–36; (2) the effects of early light phase administrat...

Introduction: Obesity-associated psychopathological co-morbidities have a negative impact on quality of life. Roux-en-Y gastric bypass surgery (RYGB) has been shown to ameliorate psychological health, however, the underlying mechanisms are not fully understood. Changes in gastrointestinal and central neuroendocrine signalling have been postulated as mediators of psychological and eating behaviour changes following RYGB. Here we assess the impact of subcutaneous infusions of th...

Background: Peptide-YY is synthesised and secreted by specialised cells in the ileum and colon. Levels increase following food intake, having a satiety effect. Baseline and postprandial levels of PYY were found to be lower in obese subjects compared to lean, negatively correlating with the subjects BMI, however obese subjects were sensitive to the anorectic effects of PYY when given exogenous PYY.Hypothesis: We have recently demonstrated that another pra...

Augurin is a putative neuropeptide product of the esophageal cancer-related gene-4. We have previously demonstrated intra-cerebroventricular (ICV) and intra-paraventricular nucleus (iPVN) administration of augurin (71–148) stimulates the hypothalamo-pituitary-adrenal axis in male Wistar rats. This effect was dependent on the release of CRH. Since CRH is known to inhibit feeding, we hypothesised augurin (71–148) would have similar actions. We therefore investigated th...

In the pancreas, PYY is expressed in a subpopulation of non-beta cells in the islets of Langerhans. The role of PYY-expressing cells in the adult pancreas is unknown. We generated a mouse model in which administration of diphtheria toxin (DT) produced specific ablation of PYY-expressing cells in the colon, pancreas and brainstem. Interestingly, DT administration to adult mice resulted in severe hyperglycaemia associated with significant loss of pancreatic insulin and disrupted...

Obesity is a major worldwide health problem with limited treatment options. Recent research has highlighted the importance of gastrointestinal (GI) nutrient sensing in the regulation of food intake and metabolism. Protein as a macronutrient induces the strongest feeling of satiety per calorie. However, different types of protein have varying effects on appetite, suggesting protein induced satiety may be due to the specific amino acids generated by protein digestion. We have id...