THE EFFECTS OF HORMONES ON THE CARBOHYDRATE METABOLISM OF THE LAMPREY LAMPETRA FLUVIATILIS

Abstract

SUMMARY River lampreys regulated their blood glucose concentration when injected with glucose. Mammalian insulin decreased the blood glucose concentration in the lamprey while adrenaline, cortisol and arginine vasotocin increased it. Glucagon had no effect initially but after a delay of 4 hr. decreased the blood glucose level. Insulin and cortisol increased the liver glycogen concentration. Adrenaline decreased the muscle glycogen concentration; vasotocin increased it. Treatment with alloxan increased the blood glucose concentration. Fat and glycogen in the lamprey are stored mainly in the skeletal muscles and their histochemical distribution in muscle is described. The results are discussed in relation to the metabolism of the migrating lamprey and the evolution of the control of carbohydrate metabolism in vertebrates.