[Hypophysian and ovarian function following a single postnatal estradiol injection. II. Studies on rats in parabiosis...

We have studied the functioning of the axis hypophysis-ovary in rats which had received an injection of 100 microgram estradiol benzoate, in the first days of life. The experimental method was the parabiosis of two animals (male or female, normal or estrogenized, intact or spayed) in different combinations. We established that estrogenization damages the hypopysis as well as the ovary to such a degree that both glands cease to function normally. --Injected gonadotrophins can procude luteinization of estrogenized ovaries. This effect, however, appears only as a direct consequence of hormone administration. Exogenous gonadotrophins can never trigger cyclical function of estrogenized ovaries.