Neuronostatin accts as a counterregulatory factor to protect against hypoglycemia

Abstract

Neuronostatin (NST) is a 13-amino acid hormone derived from the somatostatin (SST) preprohormone that exerts metabolic and cardiovascular actions in many tissue types. In transformed alpha cell lines and isolated rat islets neuronostatin enhanced low glucose-stimulated proglucagon transcription and glucagon secretion1. Additionally, neuronostatin inhibited high glucose-stimulated insulin secretion from isolated rat islets, which was mirrored in vivo in rats subjected to an intra-arterial glucose tolerance test. Rats that received a bolus injection of neuronostatin followed by infusion glucose exhibited delayed glucose disposal and impaired insulin release, causing an increased peak blood glucose1. We, therefore hypothesized the ability of neuronostatin to act as a counterregularoty factor to protect against hypoglycemia. We found that Neuronostatin administered prior to an insulin tolerance test significantly reduced hypoglycemia compared to the saline control. In addition, we found that administration of exogenous Insulin significantly reduced Neuronostatin plasma levels. These data suggest Neuronostatin may act as a counterregulatory factor in adult, male rats to prevent hypoglycemia. However, after menopause or OVX, a precipitous decline in insulin sensitivity parallels an increase in fat mass, suggesting estrogens at physiological concentrations may maintain insulin action and glucose tolerance. We therefore investigated the neuronostatin-induced blood glucose changes in conscious, cycling females. We found blood glucose levels following neuronostatin administration decreased on diestrus, when both estrogen and progesterone levels are low, but not on proestrus or estrus. From these data we conclude that the metabolic actions of Neuronostatin are modulated by sex hormone status. Further studies are required to determine the contributions of chromosomal sex and individual sex hormones to these metabolic effects of Neuronostatin.1. Salvatori AS, Elrick MM, Samson WK, Corbett JA, Yosten GL. Neuronostatin inhibits glucose-stimulated insulin secretion via direct action on the pancreatic alpha-cell. Am J Physiol Endocrinol Metab. 2014;306:E1257–E1263. Saint Louis University Internal Funds This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.