Suppressive Effect of Vasopressin on Ketosis in Diabetic Rats

In order to clarify if vasopressin (VP) plays a role in the pathophysiology of hyperosmolar nonketotic diabetic coma (HNDC), VP has been infused to diabetic rats and plasma levels of glucose (PG), ketone bodies, FFA and glucagon were determined. High-dose VP infusion (1.2 U/kg/h) caused gradual elevation of PG (60%) and glucagon levels (600%), while ketone bodies showed transient decrease (20%) at 30 min. Under the suppression of endogenous glucagon secretion by constant infusion of somatostatin (100 micrograms/kg/h), high dose VP showed 25% increase in PG levels and 30% reduction of ketone body levels for the subsequent VP infusion for 1.5 hour. Low-dose VP infusion (0.06 U/kg/h) had no hyperglycemic effect, but suppressed ketosis (20%) in the same condition. There were no changes in plasma FFA concentrations, indicating no significant effect of VP on lipolysis. The results indicate that VP often elevated in HNDC may play an important role for the pathophysiology of HNDC through suppression of hepatic ketogenesis.