Local maintenance of spermatogenesis by intratesticularly implanted pellets of testosterone in hypophysectomized rats

Abstract

The maintenance of spermatogenesis in hypophysectomized rats by means of the injection of androgen in oil was first reported by Wdsh, Cuyler and McCullagh in 1934. I n these experiments, spermatogenesis was maintained for 20 days by the daily injection of an extract of male urine. This finding was confirmed by Nelson and Gallagher ('36) who extended the period of maintenance to 39 days. Nelson ('3'7) obtained maintenance for 60 days, and later ('40) for 178 days. The animals sired litters during the latter part of the period of treatment. From control experiments in which it was found that fertility persisted in androgen-treated hypophysectoinized animals longer than did motility of sperm in androgen-treated castrates, Nelson ( '37) demonstrated that the androgen injections caused a true maintenance of spermatogenesis, not merely the prolongation of the life of the sperm which were present at the time of hypophysectomy.The injection of a large number of synthetic androgens which have not been found to occur in nature, as well as crystal-Foundation. of Philosophy, in the Faculty of Pure Science, Columbia University. 'Aided by a grant, administered by Dr. P. E. Smith, from the Rockefeller * Submitted in partial fulfillment of the requirements for the degree of Doctor TABLr; 1-Absolute and relative weights of ventral prostates and seminal vesicles of hypophysectomiaed (Hypx.), crnoperated normal and castrute rats. One group of hypophysoctomi2ed rats was untreated; the others, at the t h e the hypophysis was ablated, received implants of pellets which contained various percentages of testosterone. Autopsie8 were performed 20 days later except for the last two groups which were autopsied after 40 days. Relative Hypx.contr. = 11.00

Effect of Testosterone on Development of the Lumen in Seminiferous Tubules of the Rat*

“…The failure of testosterone to do so may indicate that an insufficient amount reaches the seminiferous cords. This possibility is consistent with the findings of Dvoskin (1944) that lower doses of testosterone are needed to maintain spermatogenesis in hypophysectomized rats when the hormone is implanted intratesticularly than when it is systemically administered. From this viewpoint it is interesting that precocious spermatogenesis has been observed in cases of androgen secreting Leydig cell tumors in prepubertal boys (Gittes et al -1970;Steinberger et al -1973).…”

Effect of Chronic Neutralization of Endogenous FSH on Testicular Function in the Adult Male Bonnet Monkey – Assessment Using Biochemical Parameters

“…The apparent discrepancy between the results observed in the rat (Males & Turkington 1970) and the monkey regarding maintenance of testicular hyaluronidase activity by testosterone in the absence of FSH and I,H could, perhaps, be due to species variation. It is well known tha.t in hypophysectomized adult rat, testosterone alone can maintain spermatogenesis, if the treatment is initiated soon after hypophysectomy (Walsh et al 1934;Dvotskin 1944;Woods 8c Simpson 1961;Lostroh 1963;Clermont Rc Harvey 1967;Steinberger 1971;Berndtson et al 1974). In man, on the other hand, testosterone treatment in cases of hypophyseal insufficiency has been repcrted to be unable to restore spermatogenesis and gonadotrophins appear to be necessary to achieve this (Gemzell E;Kjessler 1964;Mellinger & Thomson 1966;MacLeod et al 196fi;MacLeod 1972).…”