Endocrine Abstracts

Embryonic stem cells (ES cells) represent a population of self renewing pluripotent cells, capable of differentiating into derivatives of the 3 embryonic germ layers and are therefore a promising source material for generation of replacement pancreatic beta cells for transplantation in type 1 diabetes. ES cells can be induced to undergo unregulated differentiation when cultured as floating clusters (embryoid bodies). Successful generation of pancreatic endocrine cells from ES ...

Embryonic stem cells (ES cells) represent a population of self renewing pluripotent cells, capable of differentiating into derivatives of the 3 embryonic germ layers and are therefore a promising source material for generation of replacement pancreatic beta cells for transplantation in type 1 diabetes. ES cells can be induced to undergo unregulated differentiation when cultured as floating clusters (embryoid bodies). Successful generation of pancreatic endocrine cells from ES ...

Objective: The extracellular calcium-sensing receptor (CaR) is expressed on many different cell types other than those involved in the systemic regulation of plasma calcium. We have demonstrated previously that insulin-producing beta cells express the CaR. In this study we have used a calcimimetic CaR agonist (A568) to investigate the effects of CaR activation on beta cell function.Methods: Experiments used the insulin secreting MIN6 cell line or isolate...

There is no consensus on the role of insulin secreted from pancreatic β-cells in regulating its own secretion, nether in rodent islets nor in human islets. We have now investigated whether there is an autocrine signalling role for insulin in human islets by determining insulin receptor expression and assessing the effects of insulin receptor activation using a non-peptidyl insulin-mimetic termed L-783,281. All experiments used hand-picked human islets of Langerhans. Human...

Mice and rats are unusual amongst mammals for having 2 structurally similar but non-allelic insulin genes. Both genes are functional but their expression patterns relative to each other have not been conclusively determined. The insulin 1 gene (ins 1) has been shown in several studies to be selectively glucose responsive in mice and rats. We have used the MIN6 cell line to examine passage-related changes in ins 1 and 2 expression and to test glucose responsiveness of the 2 gen...

Aim: To identify the role of unmetabolised arachidonic acid (AA) produced by phospholipase A2 (PLA2) enzymes, and its 12-lipoxygenase (12-LOX) and cyclooxygenase (COX) products in the insulin secretory response of human islets of Langerhans. Material and Methods: Expression of COX-1 and COX-2 mRNAs was determined by RT-PCR. Insulin secretion from perifused human islets was measured by radioimmunoassay, in the presence of inhibitors of PLA<su...

ObjectivePlant-derived extracts have long been used to treat Type 2 diabetes mellitus (T2DM), but their effects have not been rigorously investigated at the cellular level in vitro. The aims of the current study were to determine the effects of a virgin isolate of Gymnema sylvestre (GS), designated OSA, on pancreatic β-cell function.Materials and MethodsCell viability was measured by Trypan...

Objective: To investigate pancreatic beta cell morphology and function in rat adult offspring of dams fed a high fat diet in pregnancy.Methods: Female Sprague Dawley rats were fed either a control breeding diet (4% fat) or a high fat diet (20% animal fat) balanced for vitamins and nutrients. Experimental diets were fed for 10 days prior to mating, throughout pregnancy and weaning. Weaned pups were fed standard low fat chow throughout adult life. The time...

Previous studies have demonstrated that POMC peptides are present in islets of Langerhans and suggested that ACTH-related peptides may act as paracrine modulators of insulin secretion. In order to shed light on the cellular mechanisms involved in these responses, we have carried out experiments using the MIN6 mouse insulinoma cell-line and synthetic ACTH 1-24. Following the detection of mouse ACTH receptor (MC-2) receptor mRNA by PCR amplification of MIN6 cDNA, perifusion expe...