Abstract
Intravenous injection of serotonin resulted in decrease of hepatic and diaphragmatic, as well as significant increase of cardiac glycogen 10 mins. after the injection into adrenodemedullated rats. Change of hepatic glycogen was still demonstrable 2 hrs. after the administration when the responses of cardiac and diaphragmatic glycogen were not observed. Dosage as low as 50μg failed to affect cardiac and diaphragmatic glycogen, while hepatic glycogen showed still significant reduction. Inhibition of hepatic gluconeogenesis by serotonin was demonstrated in the reduction of urinary nitrogen excretion, blood urea accumulation and hepatic glycogen content after D, L-alanine administration. The possibility that the reduction of hepatic blood flow and the resultant glycogenolysis might play some role in the change of hepatic glycogen was suggested by the result of isolated rat liver perfusion experiments. Diaphragmatic glycogen content tended to increase after subcutaneous doses of serotonin. Comparable increment of cardiac glycogen was obtained by lactate administration, and the possible participation of blood lactate increment in the effect of serotonin on cardiac glycogen was postulated.
