Epinephrine effects on carbohydrate metabolism in catfish, Ictalurus melas

Epinephrine injection in catfish, Ictalurus melas, induced (a) a rapid hyperglycemia which lasted for more than 5 hr; and (b) a slight immediate decrease of glycogen in liver and muscles (red and white), followed by an increase at 48th hr in the liver. Epinephrine, added in vitro to tissue slices, increased the output of glucose from liver and enhanced the decrease of glycogen seen in controls. Among the other organs, only white muscle showed a greater decrease of glycogen than the controls. These effects are attributed to an increase of glycogen phosphorylase activity induced by the hormone.