雄性機能とEstrogenの関係

I. 雄牛性機能に及ぼすEstrogen投与の影響

抄録

We have been interested in the facts that there are many cases of reproductive disorders in the bulls probably caused by hormonal disturbances. Some of those bulls showed a marked increase of estrogen in urine and in blood. It is still unknown whether those reproductive disorderes in the bulls are caused by endogenous or exogenous estrogen, or by the unbalance between estrogen and androgen. Besides these facts, few reports have dealt with the effects of estrogen on the reproductive function of the bull. We made, therefore, an attempt to produce the experimental damage of reproductive function with estrogen to observe the effect of estrogen on the reproductive disorders.
The data presented here were obtained from 5 bulls. The first bull was injected subcutaneously with 2. 5 mg of diethyl-stilbestrol (DES) daily for 110 days. The second one was treated with 5 mg of DES daily for 35 days. The third one was treated with 5 mg of DES daily for 30 days, and 33 days after the last treatment, he was treated additionally with 10 mg of DES daily for 14 days. Remaining 2 bulls were used as controls. The results of the experiments are as follows.
1) There was no remarkable change in the testicular volume of experimental bulls, but swelling and edema of ostium prepuce were observed only in the third bull.
2) Libido was normal or increased in early stage of.the treatment, but decreased in the latest stage of the treatment, and 2 of the treated bulls showed low libido for long time after the treatment. The ability of ejaculation became poor from the middle stage of the treatment and it took a long time befor ejaculation. They showed poor erection and could not ejaculate before they devoted themselves to mount 5-10 times, and one of them leaked out his semen without manifesting a characteristic thrust.3) The decrease in the volume of semen was observed from the middle of the treatment and it lastedto the last stage of the treatment. 'pH of semen inclined slightly to alkaline at the last stage of thetreatment.
4) The sperm motility gradually became poor and the poorest motility or necrospermia was observed at the last stage of the treatment. The recovery of the sperm motility depended on the period of the treatment, and there was a case that poor motility continued for more than 3 months after the treatment.
5) Decrease of sperm count depended on the doses of DES administrated, but at the last stage of the treatment, it was very remarkable in all treated cases. The time for recovery was controled by the degree of damage in the testicular tissue, and 6 months were necessary for the recovery in case of severely damaged one, but only 3 weeks were enough to recover in case of slightly damaged one.
6) Abnormal sperms increased after the treatment of DES. The rate of abnormal sperms became the highest at the last stage of the treatment and the highest rate continued after the final treatment.In case of the treatment of 5 mg, or 10 mg, most of the abnormal sperms were oflooped tail. In case of the treatment of 2 mg, there were many cases of abnormal head sperms and tailless ones, but few looped tail ones.
7) The contents offructose in semen increased at the beginning of the treatment, but decreased repidly at the last stage of the treatment, and kept its lower value for more thanone month. The contents of 17-ketosteroids in blood showed a similar tendency to that of fructose in semen.
8) Normal semen added with the semen plasma ofa treated bull after going removed its plasma and flushing with glycocitrate, showed the decrease its motility and livabi.lity.