Abstract
The work of Gardner and Turner 1 suggests that the immediate stimulus for mammary growth is due to the ovarian hormones, theelin and progestin. But Corner 2 and others have obtained growth with anterior pituitary preparations in rabbits which have not been exposed to the influence of corpora lutea. The possibility arises that the ovarian hormones act through the pituitary. To test this point we ovariectomized 40 rabbits and kept them for 2 months to exhaust their supply of ovarian hormones. Then by the use of Firor's 3 technique we attempted to remove their pituitaries, We were completely successful in 10 cases; of these successes, 2 occurred while we were perfecting our techniques, 4 died during the 2 months after the operation before we commenced injections. This left us with 4 successful operations which were used for injection work. We sectioned the contents of the sella turcica in each case after the experiments. Doctor B. F. Kingsbury kindly examined the sections and confirmed the fact that the pituitaries had been completely removed.
Two months after the second operation all the rabbits were injected daily with 25 R.U. of Progynon B (kindly supplied by Doctor E. Schwenk of the Schering Corporation) and of 0.5 cc. of Progestin (equal to about 4 rabbit units) made in this laboratory. These injections were made over a period of 15 days and the rabbits were then killed. The dosage used was found by Turner and Frank 4 to be effective in producing mammary development in the ovariectomized rabbit, but it cannot be considered ideal for causing progestational proliferation of the uterus. When the rabbits were killed, the mammary glands were dissected out on their muscular plates, trimmed of fat and weighed. Later, they were stained with hematoxylin, stripped from the muscle and mounted. A single ovariectomized rabbit was kept as an uninjected control and killed 4 months after the ovariectomy.
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