Effect of Stilboestrol on Certain Phases of Carbohydrate Metabolism. ∗

Carbohydrate levels in intact animals are affected not only by insulin, anterior pituitary extracts, and adrenal-cortical-hormone, but apparently also by certain sex hormones. Zunz and LaBarre 1 found an increase in blood sugar after the administration of estra-diol. Gilder and Phillips 2 showed that rats treated with this hormone had higher levels of liver glycogen when glucose-fed than did normal animals. Engelhart and Riml 3 found that the injection of corpus luteal extracts in guinea pigs increased liver glycogen. More recently, Gaunt, Remington, and Edelmann 4 administered progesterone to intact ferrets in acute experiments and found that the carbohydrate levels were elevated. However, progesterone, testosterone, or stilboestrol were without effect. Because of the potency of stilboestrol as an estrogen, we have studied its effect on carbohydrate levels after longer periods of administration.

Rats weighing from 150 to 200 g, when treatment began, received 0.05 mg of stilboestrolf subcutaneously twice daily for periods of 5,10, and 20 days. Determinations were made for blood sugar, liver- and muscle-glycogen, and urinary nitrogen, and the gonads, adrenals, and pituitaries were weighed and studied histologically.

The blood sugar level was found to be raised somewhat after only 5 days of treatment, and considerably more after 20 days. The liver glycogen was increased markedly even after 5 days of injections, and the muscle glycogen showed a slight drop after 20 days of treatment. The latter is of doubtful significance. The urinary nitrogen, determined for the last 24 hours of a 36-hour fast, was quite variable, Since it was not markedly altered in animals that were treated for 5 or 10 days, it is possible that gluconeogenesis from fat produced the increased carbohydrate levels. However, gluconeogenesis from protein might account for the heightened levels of carbohydrate in animals treated with stilboestrol for 20 days since the urinary nitrogens were increased significantly.