Estrogen and progesterone receptors in uterine leiomyomas

The purpose of our study was to evaluate the contrasting data between estrogen receptors (ER) and progesterone receptors (PgR) in uterine leiomyomas, endometrium and myometrium. Uteri were obtained from 30 women undergoing hysterectomy for uterine leiomyomas (24 premenopausal and 6 postmenopausal patients). Cytosolic and nuclear ER and PgR were analysed in uterine tissues by the method of single saturation point assay at a final concentration 5 nM of [3H-17 beta]estradiol and [3H]ORG-2058. Our results confirm that leiomyomas undergo changes similar to those observed in other uterine tissues during the menstrual cycle. The ER levels show decreased values during the postovulatory phase. After subdividing leiomyomas according to their topographic criteria, as submucous or subserosal, we observed that ER and PgR are significantly more numerous in submucous than in subserosal myomas, both in proliferative and in the secretive phase of the cycle. These results agree with the hypothesis that leiomyomas have a different etiology and may explain why some myomas decrease after progestin therapy (submucous), while others (subserosal) remain unchanged.