[Hypothalamus-hypophysis-thyroid gland system activity in altered functional state of the sex glands. 2].

The role played by the hypophysis and the hypothalamus in the interrelationship of the gonads and the thyroid gland was studied on female albino rats. Their interaction could be realized only in the presence of the intact hypophysis. The content of the thyrotropin-releasing-hormone (TRH) determined in the hypothalamic extracts altered depending on the blood estrogen level. Ovariectomy decreased the TRH content, whereas the administration of estradiol dipropionate to the operated animals increased the content of this hormone. Besides, ovariectomy caused a disturbance of the reaction of the hypophysis to TRH. Possibly the hypophysis of the castrated animals became refractory (to some extent) to the stimulating action of the TRH.