Survival of Adrenalectomized Rats After Cortical Hormone Treatment

Abstract

Within the last few years much work has been done concerning the survival of rats after adrenalectomy. 1 We had supposed that animals kept alive by injections of the cortical hormone following adrenalectomy would show approximately the same life-span after injections were stopped as those untreated after removal of the adrenals. However, in the course of other investigations in which we made prolonged cortical hormone injections into adrenalectomized rats, we found that rats show a much higher percentage of indefinite survival after extract treatment is withdrawn than they do when untreated following adrenalectomy. (Table I.)

The animals used were of a colony which had previously been shown to survive adrenalectomy for 30 days or longer in only 5% of the cases. 1 The average life-span of those not surviving adrenalectomy we had previously found to be 7 days. (A later control series of 15 animals showed an average survival of 10 days, with none surviving indefinitely.) Technique of operation and care was as previously described, except in cases to be subsequently mentioned. In all cases the injections of extract were begun at the time of operation, and given generally in divided doses twice daily—in a few cases once daily. Only the healthiest of animals were used. Ages ranged from 2.5 to 4.5 months. The cortical extract was kindly furnished by Dr. W. W. Swingle of Princeton University and Dr. Oliver Kamm of Parke, Davis & Co., to whom the authors are grateful for making this work possible. The dosage of extract given was probably in all cases far in excess of the minimum needed to maintain life.

We have observed the effects of extract treatment for varying lengths of time on 16 rats. Seven of these 16 cases survived in good condition after extract was discontinued, showed no sign of adrenal insufficiency, and were consistently gaining weight when they were killed for autopsy. In all 7 cases macroscopic cortical accessories, determined to be such by histological examination, were found on the left side near the junction of the adrenal and renal veins.