Effects of Arginine and Cold Exposure on Secretory Responses of Insulin, Glucagon and 11-Hydroxycorticosteroids in Piglets

Abstract

The effects of the intravenous injection of arginine (1.25 mmoles/kg) on plasma insulin, glucagon, 11-hydroxycorticosteroids (11-OHCS) and glucose were compared in castrated Landrace piglets between the thermoneutral (TN, 22°C) and the cold environment (2°C) groups with constant relative humidity (60%). Plasma insulin rose transiently from 8 μg/ml in initial level to 17 μU/ml 5 minutes after the arginine injection in the TN environment. Likewise, plasma glucagon rose from 122 pg/ml to 253 pg/ml. The cold exposure augmented the insulin and the glucagon responses to arginine. The 11-OHCS level before the arginine injection was 6.5 μg/dl in the TN environment. It increased significantly 4 and 7 days after cold exposure (11.9 μg/dl and 9.4 μg/dl). The arginine injection in the TN environment induced plasma 11-OHCS and glucose. These responses to arginine were augmented by the cold exposurd. The potentiation of arginine-induced insulin secretion by the cold exposure in piglets is contrast to the previous resultes obtained in sheep.