Abstract
Hypophysectomized adult rats were injected daily with (1) testosterone propionate (TP, 1, 600 or 100μg), (2) TP (100μg) and cyproterone acetate (3) NIH-ICSH-S18 (9, 3μg), (4) NIH-FSH-S9 (300, 150, 100μg), (5) NIH-FSH (300μg), rabbit ICSH-antiserum (3ml) and CA (20mg), (6) PMSG(8 or 1 IU), (7) PMSG (1 lU) and CA (10mg) for15days, or (8) testosterone depot (testosteronepro-pionate, testosterone phenylpropionate, testosterone isocaproate, and testosterone decanoate; 2mg) for a long time (30, 151, and 313 days) beginning with the next day of hypophysectomy. They were examined for the effects of these hormones on the stage of spermiogenesis by counting germ cells in stages V, VII and XII of the cycle of the seminiferous epithelium.
1.The counts of spermatocytes and spermatids in rats administered with 1, 600μg of TP or 8 lU of PMSG were close to those in normal intact controls.
2. Spermatocytes in the transitional stage from zygotene to pachytene ands permatid in the acrosomic stage and maturation phases decreased in number in rats injected with a small dose of TP or ICSH.
3. A marked decrease was observed in the number of spermatocytes in the transitional stage from zygotene to pachytene in rats of fourdifferent groups which were administerd with FSH (100 or 150μg) or TP (100μg) alone, simultaneously with PMSG and CA, or simultaneously with FSH, rabbit ICSH-antiserum, and CA respectively. There were no or only a few cap-phase spermatids which were in the process of maturation to step 8 of the acrosomic phase.
4. Many spermatids in every step of the cap-phase of spermiogenesis were observed in rats in-jected with 300μg of FSH alone. In these rats, however, the development of spermatids was disturbed remarkably in the acrosomic phase.
5. The testes decreased in weight in proportion to the prolongation of the period of injection with testosterone. The testicular weight measured on the 313th day after the beginning of injection was almost the same as that in the hypophysectomized contro1. In rats on the 313th day, germ cells of every stage were reduced in number and especially spermatids in and after the acrosomic phase decreased remarkably in number.
6. Testosterone might play a leading role in the maintenance of spermatocytes in the transitional stage from zygotene to pachytene and in the process of metamorphosis in and after step 8 of spermio-genesis. It was observed that FSH itself had no effect on hypophysectomized adult rats. It was suggested that the action of testosterone itself might be insuffcient to maintain spermatogenesis for a long time and that the synergistic action of FSH might be necessary for testosterone to continue its action in such case.
