抄録
Ovariectomy performed at mid pregnancy increased the specific binding of 125I-prolactin to the mammary gland (expressed as cpm/mg DNA) in rats 40hr after the operation. When adrenals were removed simultaneously at the time of ovariectomy, no increase in the specific binding was observed. An appreciable amount of lactose was found in all mammary glands of ovariectomized-adrenalectomized animals, though the content was less than half of that of the ovariectomized animals. The plasma level of prolactin in ovariectomized and ovariectomized-adrenalectomized rats was slightly higher than that in sham operated control rats, though the differences were not statistically significant. These results seem to indicate that the adrenal gland is necessary for the induction of the site of specific binding of prolactin in the mammary gland of the rat and that an increase in the circulating levels of prolactin does not seem to play an essential role in the initiation of milk synthesis in this species.
