Effect of Subtotal Nephrectomy upon Estrous Cycle of the Albino Rat

Abstract

In a previous study of experimental hypertension in the rat, 1 it was found that subtotal nephrectomy was followed by a progressive increase in blood pressure over a period of 3 to 4 months. Daily vaginal smears from a few females that had developed hypertension as a result of this operation revealed marked abnormalities in the estrous cycles. In view of the latter observation, it seemed advisable to obtain additional and more conclusive data on the influence of subtotal nephrectomy upon the estrous cycle. Accordingly, the estrous cycles of 40 adult, healthy female albino rats were followed by means of daily vaginal smears for a control period of 50 days. These animals were then subjected to subtotal nephrectomy by a method described previously. 1 After sufficient time had elapsed for the development of hypertension, vaginal smears were made daily for a period of 35 days. Blood pressures were recorded during the control period and again 3 to 4 months after nephrectomy. Blood pressure was measured by the method of Diaz and Levy. 2 At the end of the experimental period the animals were sacrificed and the weights of the ovaries and pituitaries recorded.

Thirteen of the animals subjected to the above procedures survived for 3 to 4 months and remained in good physical condition throughout the experimental period. Observations on these 13 animals and similar observations on 8 rats which were subjected to the same experimental procedures but whose cycles were not observed prior to nephrectomy are presented in Table 1 and Chart 1. The changes in blood pressure (Table 1) were similar to those described previously. 1 Prior to nephrectomy, the estrous cycles were, with few exceptions, normal.