Abstract
Prolactin and growth hormone were studied in their effect on the binding of radiosulfur, S35, in the costal cartilage of the hypophysectomized rat. Both hormones produced a significant increase in the S35 fixation of the costal cartilage of hypophysectomized male and female rats. Gradually increasing binding of S35 occurred with the increasing doses of prolactin. The normal male rat exhibited no change in S35 uptake when treated with prolactin. The increase in S35 fixation occurring in prolactin-treated rats was much smaller than the increment in S35 incorporation observed in animals receiving growth hormone. When both hormones were administered together no alteration in the S35 fixing pattern was noted.