Dixon, G, Nolan, J, McClenaghan, Neville, Flatt, Peter and Newsholme, P (2004) Arachidonic acid, palmitic acid and glucose are important for the modulation of clonal pancreatic beta-cell insulin secretion, growth and functional integrity. CLINICAL SCIENCE, 106 (2). pp. 191-199. [Journal article]
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Insulin-resistant states such as obesity can result in an increase in the function and mass of pancreatic beta-cells, so that insulin secretion is up-regulated and Type II diabetes does not develop. However, expansion of beta-cell mass is not indefinite and may well decrease with time. Changes in circulating concentrations of nutritional factors, such as fatty acids and/or glucose, may lead to a reduction in beta-cell mass in vivo. Few previous studies have attempted to explore the interplay between glucose, amino acids and fatty acids with respect to beta-cell mass and functional integrity. In the present study, we demonstrate that culture of clonal BRIN-BID II cells for 24 h with the polyunsaturated fatty acid arachidonic acid (AA) increased beta-cell proliferation and enhanced alanine-stimulated insulin secretion. These effects of AA were associated with significant decreases in the cellular consumption Of D-glucose and L-alanine as well as decreased rates of production of nitric oxide and ammonia. Conversely 24 h exposure to the saturated fatty acid palmitic acid (PA) was found to decrease beta-cell viability (by increasing apoptosis), increase the intracellular concentration of triacylglycerol (triglyceride), while inhibiting alanine-stimulated insulin secretion. These effects of PA were associated with significant increases in D-glucose and L-glutamine consumption as well as nitric oxide and ammonia production. However, L-alanine consumption was decreased in the presence of PA. The effects of AA, but not PA, were additionally dependent on glucose concentration. These studies indicate that AA may have a critical role in maintaining the appropriate mass and function of islet beta-cells by influencing rates of cell proliferation and insulin secretion. This regulatory effect may be compromised by high circulating levels of glucose and/or PA, both of which are elevated in Type II diabetes and may impact upon dysfunctional and apoptotic intracellular events in the beta-cell.
|Item Type:||Journal article|
|Faculties and Schools:||Faculty of Life and Health Sciences|
Faculty of Life and Health Sciences > School of Biomedical Sciences
|Research Institutes and Groups:||Biomedical Sciences Research Institute|
Biomedical Sciences Research Institute > Diabetes
|Deposited By:||Professor Peter Flatt|
|Deposited On:||14 Jan 2010 15:38|
|Last Modified:||15 Jun 2011 11:10|
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