THE EFFECT OF ESTROGENIC SUBSTANCES UPON THE PITUITARY, ADRENALS AND OVARIES1

Abstract

Although there is abundant experimental evidence that the estrogenic hormones exert an influence upon the pituitary, the nature and extent of this influence is not entirely clear. The working hypothesis that gonadal hormones suppress the pituitary, making available to the organism a reduced amount of gonad-stimulating secretion was advanced by Moore and Price (1) in 1930. They felt that results obtained by them in a large number of careful experiments, as well as certain observations of other investigators, could be explained on such a basis. In support of this concept is the work of Meyer, Leonard, Hisaw and Martin, who reported that long-continued injections of estrin resulted in a decreased ovarian-stimulating capacity of the pituitary of the adult rat (2) and in an ovarian depression in the immature animal (3). The latter observation was confirmed by Spencer, Gustavson and D’Amour (4) and by Doisy, Curtis and Collier (5). Kunde, D’ Amour, Gustavson and Carlson (6) found a reduction in the size of pituitary and ovaries following prolonged estrin injections in immature dogs. It should be noted, however, that these animals showed a pronounced hyperplasia of the thyroid. Previous to the publication of the above results, an effort to investigate the effect of estrin on the pituitary had been made in this laboratory by Burch and Cunningham (7). The only estrogenic preparation available to us at that time was a commercial alcoholic extract of human placenta2 containing a high percentage of estrin. Castrate rats injected over a short period of time with large doses of this extract showed a marked increase in the ovarian-sitmulating capacity of the anterior pituitary.