Morphological Comparison of Anterior Pituitaries of Normal Castrated Female Rats and Those Receiving Injections of Pregnancy Urine Extracts.

Abstract

It has been reported by Severinghaus and Wolfe, Ellison and Rosenfeld, that while injections of extracts of pregnancy urine result in marked changes in the anterior pituitaries of normal female rats, such extracts are without action on the anterior pituitaries of castrated female rats. In our previous reports, detailed data were not given; in this report we wish to present quantitative data which demonstrate that the anterior pituitaries of non-injected castrated female rats (both mature and immature) are morphologically indistinguishable from those of female rats receiving injections of extracts of pregnancy urine. Sixty-five virgin mature and 31 immature female rats were castrated. The mature females were sacrificed at 15 and 30 day intervals after operation. Forty-one of these rats received from 25 to 75 units of an extract of pregnancy urinet daily throughout the 15 day castration period or for the last 15 days of the 30 day castration period in those rats which were sacrificed after 30 days. All immature rats were between 25 and 30 days old at operation, and were sacrificed 15 days after operation. Sixteen received 25 units of pregnancy urine extract daily for the entire period; 15 littermate sisters served as controls. At autopsy the pituitaries were weighed and fixed in Regaud's fluid. Serial sections of all glands were cut. Complete cell counts were made on 5 sections from each of the 90 glands, A total of 331,056 cells were counted. The quantitative results of these studies are presented statistically in Table 1. (Frequency distribution, means and standard deviations are given). Analysis of this table reveals that the percentages of the various cell types in the anterior pituitaries of the injected rats were almost identical to the percentages of these cells in the anterior pituitaries of the control rats castrated for a similar period of time.