ADDITIVE EFFECTS OF TESTOSTERONE AND INSULIN ON GLYCOGEN CONTENT AND 2-DEOXYGLUCOSE PHOSPHORYLATION IN RAT LEVATOR ANI MUSCLE

Both testosterone propionate and insulin increase the glycogen content in levator ani muscle of diabetic rats. Glycogen increses are additive at high doses of both hormones. Testosterone increases both xylose uptake and 2-deoxyglucose (dGlc) phosphorylation without affecting free dGlc intracellular levels. Insulin, if added in vitro, enhances xylose uptake and both free dGlc and 2-deoxyglucose 6-phosphate (dGlc-60P) in the intracellular water. Insulin administration in vivo, however, increases dGlc-6-P levels only. Testosterone and insulin effects on xylose uptake are not additive, whereas administration of insulin, both in vivo and in vitro, increases muscle dGlc phosphorylation additively with respect to the testosterone effect. The testosterone and insulin effects on sugar phosphorylation and their importance in stimulating muscle glycogen synthesis are discussed. © 1969.