Glucose, lactate, insulin, and somatostatin responses to endotoxin in developing rats

The purpose of this study was to examine the temporal plasma glucose, lactate, insulin, and somatostatin responses of 10-day-old (10 d) and 28-day-old (28 d) rats to the effects of an LD90 dose of endotoxin for a 4 h period. Salmonella enteritidis endotoxin was administered to 10 d and 28 d rats at .2 and 30.0 mg/kg, respectively. Hyperglycemia was the initial response to endotoxin, followed by hypoglycemia; this was similar for 10 d and 28 d rats. Lactate levels were significantly elevated in 10 d rats, but only mild hyperlactacidemia was observed in 28 d rats. Hyperinsulinemia was observed in both 10 d and 28 d rats in response to elevated glucose levels; in 10 d rats, decreased insulin levels preceded the hyperinsulinemia. Plasma somatostatin levels were elevated in both 10 d and 28 d rats in response to endotoxin, but the endotoxin-induced somatostatin levels were greater and occurred earlier in 28 d rats than in 10 d rats. The magnitude of the somatostatin response to endotoxin in the developing rats was markedly less than that previously reported in adult rats. Since previous reports indicated that somatostatin supported the glucoregulatory adaptive response to endotoxin in adult rats, the present results suggested that the diminished somatostatin response to endotoxin in developing rats may partially underlie their increased sensitivity to endotoxin and the profound glucose dyshomeostasis that results subsequently.