Effects of insulin on glycogen metabolism in isolated and perfused catfish liver.

The isolated and perfused catfish liver showed (a) a decrease in liver glycogen, (b) a continuous increase in glucose output, and (c) a decrease of lactate in the medium. Insulin did not influence liver glycogen decay during the first 2 hr; thereafter the hormone induced an increase of glycogen, particularly when glucose was added into perfusate. In insulin treated liver, the glucose output was lower than controls in the first hours of perfusion; thereafter a re-uptake of glucose occurred. After 2-3 hr of perfusion, the lactate present in the medium was increased by insulin towards the starting level. The long lasting effects of insulin on catfish in vivo were confirmed.