Injurious Action of Pitressin on the Rat Testis. ∗

Abstract

Some of the biological effects of adrenocorticotropic pituitary preparations suggested the presence of a pressor substance. A temporary prostration of the rats was observed invariably to follow injections of high levels of these partially purified preparations. Co-incidentally it was noted that there were injurious effects of high levels of these preparations on the testes of normal and hypophysectomized males. Two methods have been employed in the effort to determine whether the injurious effects on the testes may be referred to pressor principles. First, attempts were made to remove any pressor substance from ACT preparations and to compare the biological properties of the crude and purer materials. This phase of the subject will be discussed later. Second, effects of the pressor principle itself on the testis have been studied and are here reported.

As a maximum of 5 dog pressor units per mg have been found in ACT preparations, pitressin† was injected into normal 40-day-was old male rats for a period of 15 days, at a dose of 5 pressor units daily. As can be seen in Table I, the tetis was definitely decreased in weight by this treatment—almost halved.‡ Spermatozoa were absent in the epididymis, or were present in small numbers only, whereas the epididymis of the normal controls (55 days old) contained abundant spermatozoa. Histologically, the testes showed varying degrees of injury. The normal testis of the rat at this age contains tubules of uniform caliber, which have not yet attained their maximum diameter, and mature spermatozoa or spermatids are found in practically all tubules. The interstitial cells have acquired a considerable body of cytoplasm and are epithelioid rather than “connective tissue like.” After pitressin treatment, the tubules were usually lined by spermatocytes; sometimes spermatids were present and occasionally a few abnormal spermatozoa.