Effect of removal of the adrenal medulla on the hormonal response induced by acute hepatic vagotomy

Abstract

The purpose of the present study was to determine the effects of an acute hepatic vagotomy on plasma insulin and catecholamines levels in fasted and fed rats with and without adrenodemedullation. Rats were first divided into two groups: adrenodemedullated (ADM) and non-adrenodemedullated rats, each group being subdivided into a normally fed and a fasted (14 hrs) group. Anesthetized rats were first ADM or sham operated, and a jugular catheter was inserted. The first blood sample was taken 30 min later (time 0). Rats were then hepatic vagotomized (HV) or sham operated, and the second blood sample was taken 30 min after the HV. Results (0 vs 30 min) indicate an increase in plasma glucose, epinephrine, and norepinephrine concentrations in rats non-adrenodemedullated. This effect was independent of the nutritional state and the integrity of the vagus nerve. A weakly significant (P < 0.07) effect of the HV on insulin response was found in ADM rats, independently of the fed or fast state (different levels of hepatic glycogen content). These results indicate the necessity of using ADM animals to study the effects of an acute HV. They also suggest that the hepato-pancreatic axis is not influenced by the level of hepatic glycogen.