THE BIOLOGICAL ASSAY OF THE MAMMOGENIC DUCT GROWTH FACTOR OF THE ANTERIOR PITUITARY¹,²

Abstract

IT HAS BEEN established that the ovarian hormones are ineffective in stimulating mammary gland growth in hypophysectomiz,ed male guinea pigs, mice and rats, and in female rabbits, cats, ground squirrels and guinea pigs (1, 2, 3, 4, 5,6, 7). That the pituitary was necessary for the action of estrogen upon the mammary gland was concluded by Selye et al. (8). Contrary results, however, have been reported by several investigators (9, 10). Ruinen (10), was unable to secure localised growth of mammary glands with estrogen painted on the skin. A large number of experiments always gave equal development of all glands. Injection of desiccated whole pituitary powder from non-pregnant sheep was ineffective in stimulating mammary gland growth in three hypophysectomiz; ed immature female guinea pigs (4). One hypophysectomised and one castrated male rat showed no mammary gland growth after 30 daily implants of normal adult rat pituitaries.