Islet Release of ACTH-Like Peptides and their Modulatory Effect on Insulin Secretion
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The B-cell secretion of insulin in response to glucose is modulated by different hormones1,5. Some of these hormones are produced by non-B islet cells and also by the B-cells themselves. Among these hormones, the presence of POMC6 and some of its derivative products such as endorphin7,8, ACTH9 and corticotropin-like intermediate peptide10 has been identified in the islets. It has not yet been established whether the endogenous islet POMC and its derivatives play any modulatory role in the secretion of insulin. On the other hand, it has already been reported that ACTH enhances the secretion of insulin in response to glucose11,12. Such effect has been attributed to its stimulation on islet adenylate cyclase13 and to the consequent increase of 3′5′-cAMP14 in islet content, but the mechanism by which ACTH stimulates the release of insulin is not clear.
KeywordsInsulin Secretion ATPase Activity Insulin Release Krebs Ringer Bicarbonate Buffer Islet Content
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- 6.H. Zuhlke, U. Lendeckel, A. Zinke, and G. Jesse, Regulation of expression of proopiomelanocortin gene in isolated islets of Langerhans, Diabetologia (abstract) 32:560A (1989).Google Scholar
- 8.W.R. Niendorf, and H. Zuhlke, Biosynthesis of a-endorphin in pancreatic islets of neonatal Wistar rats, Biomed. Biochim. Acta 44:51 (1985).Google Scholar
- 23.I. Atwater and P.M. Beigelman, Dynamic characteristics of electrical activity in pancreatic B-cells, J. Physiol. 72:769 (1976).Google Scholar
- 24.I. Atwater, Control mechanisms for glucose-induced changes in the membrane potential of mouse pancreatic B-cell, Cien. Biol. Portugal 5:299 (1980).Google Scholar