The effect of the sex hormones on the growth of transplanted mammary adenofibroma in rats.

Abstract

This study reports on an experiment involving normal female rats, castrates of both sexes, and estrogen-injected castrates to determine whether or not estrogenic hormones are capable of influencing transplanted adenofibroma. A total of 469 normal and castrated rats were given injections of estrogen and testosterone after tumor implantation in the region of the right inguinal mammary gland. The injection of estrogen raised the growth rate of tumors in castrates to 2.0 mm/week. Castration does not appreciably affect the number of successful implants in males, the takes in the normal males being 24.3% and in the castrates 22.2%. Injection of testosterone propionate in a small group of castrate females resulted in successful growth in 40%; in castrated males there was a 46.1% take. These results do not indicate any inhibitory effect of testosterone on adenofibroma. Estrogenic hormone is the important endocrine factor determining the successful transplantation of mammary adenofibroma in rats. The stimulatory effect of estrogenic hormone upon mammary adenofibroma is probably exerted indirectly through the "mammogenic hormone" of the anterior pituitary. The transplantibility and growth rate of adenofibromas may be altered by hormonal means since this tumor responds like the normal mammary gland to the ovarian and pituitary hormones.