Neuropeptide Plays Role in Appetite, Islet Cell Growth
Animal study suggests melanin concentrating hormone regulates insulin-producing cells
TUESDAY, Jan. 30 (HealthDay News) -- Melanin concentrating hormone, or MCH, a neuropeptide implicated in appetite regulation, is involved in regulating the mass of insulin-producing pancreatic islet cells and the secretion of insulin, according to the results of a study published in the February issue of Diabetes.
Rohit N. Kulkarni, M.D., Ph.D., of Harvard Medical School in Boston, and colleagues examined the expression of MCH in pancreatic islets and studied mice lacking MCH. The investigators had previously found that mice overproducing MCH were only mildly obese but produced high levels of insulin and had an increased mass of pancreatic islet beta-cells.
The researchers found that MCH and its receptor were expressed in both mouse and human islets, and MCH enhancement of insulin secretion in both cases was dose-dependent. Mice lacking MCH had a significantly reduced mass of pancreatic islet beta-cells, and these mice had a smaller increase in beta-cell mass after being fed a high-fat diet compared with normal mice. Islets from these mice also had altered expression of islet-enriched genes, the report indicates.
"Together, these data provide novel evidence for an autocrine role for MCH in the regulation of beta-cell mass dynamics and in islet secretory function and suggest that MCH is part of a hypothalamic-islet (pancreatic) axis," Kulkarni and colleagues conclude.