Effect of glucagon on the metabolism of the eel, Anguilla japonica.

Abstract

In both hypophysectomized and intact eels, a single injection of glucagon at a dose of 0.1 mg kg−1 rapidly evokes a marked hyperglycemic response and an increase in total ammonia excretion. In the intact eel, there is a transient decline in liver glycogen levels. In hypophysectomized eels, the liver glycogen is already low and no further drop is recorded. Instead there is a significant transient decline in muscle glycogen levels. From the metabolic balance sheet constructed by combining data on changes in nitrogen excretion, respiratory exchange, and metabolite content in serum, liver, and parietal muscle, it becomes apparent that during 0 to 2 hr after glucagon administration, there is an increase in net nitrogen and carbohydrate catabolism while fat is not utilized. A concomitant decline in serum lipids appears to be due to uptake into cells without oxidation. The mobilization of protein as the major metabolic substrate is facilitated by stimulation of hepatic glutamate-oxaloacetate transaminase enzyme activity.