Relation of Anterior Pituitary to Sexual Differences in Ketosis in the Rat

Abstract

Burn and Ling 1 have reported that the administration of an alkaline extract of the anterior pituitary gland to female rats fed on a butter fat diet brought about a marked rise in the level of ketonuria. The experiments on males were uniformly negative. In order to determine whether the sexual differences in ketonuria reported in the previous paper 2 might be traced directly or indirectly to this keto-genetic hormone, further experiments under varying conditions seemed advisable.

The experimental procedure was similar to that used in the previous work. 2 The extracts of anterior pituitary were made from fresh glands of steers according to the procedure of Burn and Ling. 1 The administration of this extract to normal or castrated male or female rats which were receiving diacetic acid resulted in a marked rise in the level of acetone bodies in the urine over that of the controls. The response was as prompt and as great in male as in female rats and in the castrated as the normal animals. No glycosuria was observed. The following is the number of experiments which were made on the anterior pituitary extract and all were strongly positive; normal males, 9; castrate males, 14; normal females, 11; oophorectomized females, 14.

When the anterior pituitary extract was injected in normal male and female rats which were fasted but to which 10% NaCl was administered instead of diacetic acid, the excretion of acetone bodies in the urine was promptly increased from an average of about 1 mg. per day to 30-65 mg. No sexual difference in response was noted. Boiled extract was inactive as was the filtrate after an alcoholic precipitation of the active extract. Negative results were likewise obtained when an active extiract was fed by stomach tube instead of being injected subcutaneously.

It seems that the greater susceptibility of the female to ketosis may be associated with a larger production of the ketogenetic substance in the anterior lobe as the result of the stimulation of some substance produced in the ovary other than theelin.