Hormonal secretion in male rats chronically treated with [D-Trp6, Pro9-NEt]-LRF.

Effects of various doses of testosterone propionate on intratesticular and plasma testosterone levels and maintenance of spermatogenesis in adult hypophysectomized rats

Hypophysectomized rats maintained with 2 mg pregnenolone have low plasma testosterone levels, but rete testis levels are normal. This model system was used to examine the importance of androgen-binding protein (ABP) in maintaining high luminal androgen concentrations for the development and maintenance of sperm fertilizing ability in the epididymis. Hypophysectomized rats were injected with pregnenolone (1, 0.5, 0.2, or 0.02 mg/100 g BW) for 14 days, starting 1 day after surgery. Sham-operated rats and a group of hypophysectomized rats were injected with oils as controls. At the end of the experimental period, sperm fertilizing ability, tissue weights, ABP, and testosterone levels were determined. The 1- and 0.5- mg doses of pregnenolone resulted in rete testis testosterone levels that were 67% and 29%, respectively, of the levels found in sham-operated animals. Plasma testosterone levels were not different from levels found in hypophysectomized, oil-injected controls with any of the pregnenolone doses. T...

Investigations on the relationship between sperm fertilizing ability and androgen-binding protein in the hypophysectomized, pregnenoloneenolone-injected rat.

Effects of Testosterone and Dihydrotestosterone on Spermatogenesis, Rete Testis Fluid, and Peripheral Androgen Levels in Hypophysectomized Rats

The control of androgen concentrations in the intraluminal fluids of the male reproductive tract is not well understood. The present experiments were performed to determine the effects of hypophysectomy, hypophysectomy plus testosterone (T), and hypophysectomy plus pregnenolone treatment on intraluminal androgen concentrations in the adult rat testis and epididymis. T and 5 alpha-dihydrotestosterone (DHT) concentrations were determined in the vascular, interstitial, and intraluminal compartments of the epididymis. Testicular and epididymal morphology also were examined under light microscopy. Hypophysectomy of at least 5 days duration significantly reduced T and DHT concentrations in serum, tissues, and intraluminal fluids of the reproductive tract. T replacement for 14 days, which produced peripheral T concentrations of 5 ng/ml, did not support intraluminal androgen concentrations in the seminiferous tubules equivalent to controls; rete testis androgen concentrations were similar to controls, however. Pregnenolone administration at 2 mg X rat-1 X day-1 for 14 days did not maintain spermatogenesis nor intraluminal T concentrations in the seminiferous tubules equivalent to controls; however, a low level of spermatogenesis continued when intraluminal and tissue androgen concentrations were maintained at 10-20% of controls by either the testosterone and pregnenolone treatments.

Androgens in male rat reproductive tract fluids: hypophysectomy and steroid replacement.

Adult hypophysectomized male rats were treated with 2 mg⁄day of testosterone propionate, pregnenolone, 17α-hydroxypregnenolone, progesterone or 17α-hydroxyprogesterone. The treatment commenced on the day of surgery and was continued for 4 weeks. In all steroid treated animals, spermatogenesis was qualitatively maintained. Sex accessory organs were maintained only in testosterone propionate treated animals. In C21 steroid-treated rats the sex accessory organs showed atrophy similar to untreated hypophysectomized animals suggesting lack of peripheral conversion to androgens. However, administration of 3Hpregnenolone with the last injection of pregnenolone resulted in the isolation of a considerable amount of 3H-testosterone from testicular tissue of the experimental animals. This finding suggests that maintenance of spermatogenesis in pregnenolone treated animals could have been due to testosterone formed in the testes from the exogenously administered pregnenolone. (Endocrinology 96: 1319, 1975)

H. Roll

Papers

Effects of C21 steroids on sex accessory organs and testes of mature hypophysectomized rats.