THE INFLUENCE OF CORTICOTROPIN ON KETONEMIA AND GLYCEMIA IN NORMAL AND ADRENALECTOMIZED RATS

Abstract

Blood ketone and sugar levels were measured for 3.5 hours after intraperitoneal injection of several different preparations of corticotropin and of cortisone aldehyde into 24 hour fasted normal and adrenalectomized rats, with and without Nembutal anesthesia. In unanesthetized rats, only comparatively large doses of corticotropin induced ketonemia (10-40 U.S.P. units). There was no correlation between ketogenic and ACTH activity per se. Cortisone aldehyde did not influence blood ketones in unanesthetized rats. In anesthetized rats all samples of corticotropin tested were ketogenic, some in minute doses, i.e. 30 [mu]g. Ketonemia was well established within 30 minutes of injection. Cortisone aldehyde had no appreciable effect on ketonemia in 3.5 hours. The ketogenic response to oxycel purified corticotropin was associated with a concurrent fall in blood sugar, beginning in about 60 minutes while that after commercial corticotropin (Wilson) was not. In the former cases there was a good correlation between the rise in ketones and the fall in blood sugar. The ketogenic response to oxycel purified corticotropin persisted in DCA or cortisone maintained adrenalectomized rats, although 20 times more hormone than in normal rats was necessary to elicit it in the absence of the adrenal. Ketonemia in the adrenalectomized rats was associated, in general, with a fall in blood sugar. The ketogenic response to corticotropin is interpreted as an extra- adrenal response. It appears to be independent of ACTH activity per se, as expressed in units by the adrenal ascorbic acid depletion method, and hence presumably represents a separate principle.