Abstract
The effects of experimentaly induced hypo-and hyperthyroidism on the ovarian response to pregnant mares' serum, or chorionic gonadotrophin were determined in immature rats by administering thiouracil for 7 to 14 days and desiccated thyroid solution for 7 days. A constant dose of PMS or HCG was injected into each animal. It was found that administration of thiouracil or thyroidectomy significantly increased the action of the pregnant mares' serum on the ovaries. However, this effect was not observed in hypophysectomized rats, the same was not observed on the action of HCG. When desiccated thyroid solution was administered to rats, there were significant decreases in ovarian response to PMS. The same results were also obtained in hypophysectomized rats. Furthermore, action of estrogen on the uterus was altered by the amount of thyroxine administered.
