Abstract
The ratio of the amounts of thyrotropic hormone in rat and beef hypophyses is entirely different from the ratio of the interrenotropic content in pituitaries of these 2 animal forms. Per unit of weight, adult male rat hypophyses are 7 to 9 times as potent in thyrotropic hormone as beef glands, whereas bovine pituitaries exceed male rat hypophyses in the ability to hypertrophy the adrenal cortex of adult male rats.
Intramuscular implants into immature male guinea pigs and subsequent histological study of the thyroids showed that as good a response can be elicited with 6 mg. of male rat pituitary as with 50 mg. of beef.
The adrenal weight is almost doubled when 1800 mg. of bovine glands are implanted over a 5 to 10 day period into adult male rats, provided the recipients have not been thyroidectomized. 1 On the other hand, as many as 200 (about 1600 mg.) adult male rat hypophyses implanted into intact rats produced no adrenal enlargement whatsoever; however, 350 whole glands administered to one rat did induce adrenal hypertrophy. Preliminary work indicates that adrenalectomy greatly increases the interrenotropic capacity of rat pituitaries, which, as we have just seen, is normally very low compared with the thyrotropic content.
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