Effects of Niacin and Vitamin C on Blood Sugar

Intramuscular injection of niacin in normal rats induces hyperglycemia which lasts approximately 1 hour. In adrenalectomized rats niacin produces a hypoglycemia. Subcutaneous injection of vitamin C lowers blood sugar in normal and diabetic rabbits, the effect being pronounced when the blood level of vitamin C is high. The simultaneous administration of niacin and vitamin C produced a pronounced hypoglycemia. The rise in blood sugar normally produced by niacin is nullified if vitamin C is injected simultaneously or shortly thereafter. In both normal and diabetic animals, vitamin C injections produce an increase in liver glycogen. The vitamin C content of liver is lower in normal than in alloxan diabetic animals.