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

Abstract

The respiratory and intermediary metabolism of the eel responds to a single injection of cortisol given at 1 mg kg−1. Cortisol increases oxygen consumption rate, depresses the respiratory quotient, and elevates ammonia and K+ excretion rates in both intact and hypophysectomized eels. The response shows a lagtime of several hours and rises to peak values at 9 hr. In the hypophysectomized eel cortisol induces a rapid increase in blood glucose at 2 hr accompanied by continued rises in serum α-amino acid levels and hepatic glutamate-oxaloacetate transaminase activity. At 9 hr, deposition of liver glycogen is detected and total liver protein and total hepatic glutamate pyruvate transaminase, glucose-6-phosphatase, and fructose-1,6-diphosphatase content become elevated. Liver fat increases at 24 hr accompanied by a slight reduction in serum lipids. According to the metabolic balance sheet, the data suggest that the carbon skeleton used for the synthesis of blood glucose and liver glycogen comes from the breakdown of peripheral tissue such as muscle, releasing fat and amino acids for gluconeogenesis in the liver.