[Changes of sex steroid hormone receptors in rat uterine cytosol during experimental induction of endometrial carcinoma (author's transl)].

The sex steroid hormone receptor levels of uterine cytosol were assayed in the course of experimental induction of endometrial carcinoma in rats. Effects of administration of various hormones on the receptor levels were examined with each histological pattern of endometrium. 1) The dissociation constants for E2 and R5020 bindings with uterine cytosol were almost fixed in spite of various histological patterns of endometrium. 2) The influence of administrated hormones on the receptor assay system could be neglected by the preincubation of uterine cytosol with DCC for five times. 3) By the administration of DES for six weeks, estrogen receptor levels were increased significantly in adenocarcinoma, while progesterone receptor levels did not show the tendency of decreasing. 4) By the administration of MPA combined with DES, estrogen receptor levels were not decreased significantly in both atypical adenomatous hyperplasia and adenocarcinoma; progesterone receptor levels were decreased in all groups. 5) By the administration of MPA, estrogen receptor levels were decreased significantly in adenocarcinoma. These data suggest that receptor levels can be controlled by the administration of sex hormones in the course of development of endometrial carcinoma.