Reactions of Ant. Pituitaries of Male Rats to Administration of Ant. Pituitary-Like Substance and to Oestrin.

Abstract

Recent studies indicated that injections of massive amounts of oestrin into normal female rats induced weight and morphologic reactions in the anterior pituitary similar to those obtained by the injection of the anterior pituitary-like substance of pregnancy urine. Both of these substances induced a marked weight increase in the gland, a marked loss of granules from the basophiles and a less evident loss of granules from the eosinophiles (in A.P.L. rats whose ovaries contained active corpora lutea). Furthermore, it has been found that administration of the A. P. L. factor has no action on the anterior hypophysis of the castrated rat, but that oestrin is capable of direct action on the anterior lobe of the castrated rat. The experiments described below were carried out in order to compare the reaction of normal male rat pituitaries to administration of these 2 factors. Fourteen adult male rats received daily injections of 25 rat units of an extract of pregnancy urine for 10 days. Another group of 10 rats received daily injections of 200 rat units of oestrin for 10 days. A third group of 30 normal mature male rats served as controls. At autopsy, body, pituitary, testes and prostate and seminal vesicle weights were secured. Serial sections of all glands were cut. 5 representative sections from each series were studied and cell counts made. Quantitative results are presented in Table I. Administration of the A. P. L. substance to male rats did not increase the weight of the pituitary gland over that found in the controls (Table I). This was in contrast to previous findings in female rats. Confirming the findings of Severinghaus the anterior pituitaries of the injected male rats exhibited a marked loss of granules from practically all the basophiles although a few granular basophiles were present (Table I).