EFFECT OF ADRENALECTOMY ON THE LACTOGENIC HORMONE AND INITIATION OF LACTATION1,2

Abstract

The effect of adrenalectomy on the lactogen content of the pituitary was detd. in 2 groups of [female] albino rats totalling 33 animals. There was a reduction of 27.5 and 25.7%, respectively, in hormone content on a body-wt. basis, as compared with normal intact rats of the same sp. This reduction in pituitary lactogen following adrenalectomy may be due to a direct inhibitory effect on the pituitary, suspension of the estrous cycle, or reduction in food intake. The adm. of 1000 I.U. of estrone to 10 intact [female] albino rats increased the average lactogen content of the pituitary by 216.9% on a body-wt. basis, while the same amt. of estrone injected into 14 adrenalectomized rats increased the avg. lactogen content of the pituitary by only 104.5 per cent. [male] and [female] guinea pigs which were adrenalectomized and received estrogen showed increases in pituitary lactogen equal to those obtained in intact guinea pigs. However, inasmuch as most of these guinea pigs survived but a few days after adrenalectomy, it is impossible to conclude that the full effects of adrenalectomy were operative on the pituitary. Adrenalectomy of [female] albino and white-hooded rats during the last wk. of pregnancy did not prevent the postpartum rise in the lactogen content of the pituitary, which was found to be equal to that present in intact rats at 48 hrs. after parturition. Milk was present in the mammary glands of the adrenalectomized mother rats and also in the stomachs of their living young, but not in amts. equaling that found in intact rats and their offspring. The failure of rats adrenalectomized during pregnancy to lactate sufficiently following parturition is evidently not due to a deficiency of lactogenic hormone in the pituitary.