Metabolic effects of glucagon in the young pig

The i.v. infusion or i.m. injection of 30 micrograms x kg-1 of glucagon into pigs aged 3--9 d, 24--30 d and 42--56 d was followed by a rise in the rate of oxygen consumption. In pigs aged 3--28 d pretreatment with 3 mg/kg of the beta-blocker propranolol prevented the rise in oxygen consumption after glucagon. Glucagon also caused a rise in plasma glucose which persisted for 60 min in 3--9 d old pigs. In older animals the glucose concentration first increased and then decreased below the control value after 45 min before rising again. The plasma concentration of free fatty acids did not change. In older pigs glucagon often induced shivering which occurred after the initial rise in metabolic rate. This effect which was accompanied by an increase in body temperature could be blocked with indomethacin, but the initial rise in metabolic rate, which was not associated with shivering, persisted.