下垂体抽出液投与によるラットの過排卵誘起と初期胚発生の観察

抄録

As a part of studies to research the possibility of superpregnancy, the early development of fertilized ova which were induced superovulation by the administration of pituitary extract to female rat was observed. Pituitary gland removed from 3-10 months old male rat was homogenized and centrifuged. The supernatant fluid extracted from one pituitary was administered to 3-6 months old female rat at rletestrus. Effects of the pituitary extract injection on ovulation, recovery rate of ova and development of ova in pregnant rat were investigated.
1. In all immature rats treated, the age at vaginal opening was advanced. But the timing of the first ovulation was not affected by administration of pituitary extract.
2. In most of 3-6 months old rats ovulated, the number of ova ovulated was more than 20 and the average of them was 22.8±8.9. On the other hand, in most of rats over 7 months old, the number of ova ovulated was less than 20 and the average of them was 13.3±5.8.
3. Nine of nineteen treated adult female rats were induced superovulation at following estrus and were copulated by fertile male. Mean number of ovulated ova of treated rat was about twofold that of control one on day 1 of pregnancy.
4. Recovery rate of ova on day 3 and 5 of pregnancy in the treated rats were lower (68.9 and 67.0%, respectively) than those of control rats (88.6 and 82.7%, respectively).
5. Large vesicular ovarian follicles were not observed during their early pregnancy.
In conclusion, the pituitary extract acted on ovaries of all treated rats and promoted the growth of their ovarian follicles. Especially, in 3-6 months old rats, administration of the pituitary extract induced superovulation frequently and did not interfere with the early development of fertilized ova in pregnant rats.