Role of somatostatin in glucose regulation during endotoxicosis in the rat

Abstract

This study assessed the role of somatostatin in regulating glucose homeostasis during endotoxicosis in the rat. Plasma levels of somatostatin, glucose, lactate, insulin, and glucagon were measured in control and endotoxin-treated rats. Cysteamine was used to block endogenous somatostatin release before endotoxin treatment. Early during the course of endotoxicosis, plasma levels of somatostatin-like immunoreactivity (SLI) were significantly elevated along with glucose, lactate, insulin, and glucagon. Pretreatment of endotoxic rats with cysteamine virtually blocked the elevated SLI levels and prevented the early appearance of hyperglycemia. Endotoxin-induced increases in lactic acid and glucagon levels were attenuated by cysteamine pretreatment, but elevated insulin levels were not appreciably altered. Elevated somatostatin levels appeared to support the occurrence of the early hyperglycemia and prevent the development of late hypoglycemia during endotoxicosis by sustaining elevated glucagon levels and thus facilitating the maintenance of glucose levels. The results suggest that somatostatin plays a significant role in the glucoregulatory response to endotoxicosis. Endotoxicosis may alter the relative "physiological" ability of somatostatin to inhibit the secretion of insulin and glucagon.