Oestrogen and progesterone receptor status and PgR/ER ratios in normal and myomatous human myometrium

The concentration and molecular properties of the oestrogen (ER) and the progesterone (PgR), present in normal myometria and uterine leiomyometria, obtained from a group of age-matched, pre-menopausal, negroid female patients were investigated. Serum oestrogen and progesterone levels did not differ significantly in the two groups. Significant differences were detected in ER and PgR levels between normal and leiomyomatous myometria. Both ER (154%; p < 0.0001) and PgR (33%; p < 0.05) were significantly increased in uterine leiomyomas. PgR levels were less affected than the ER levels, causing a significant decrease (44%; p < 0.05) in the PgR/ER ratio in myomatous myometria. Dissociation and sedimentation constants, as well as iso-electric points of ER and PgR were essentially similar in normal and in myomatous myometria. According to our results, tissue pathology does not appear to be associated with defects in the molecular properties of ER and PgR, but with differential changes in the ER and PgR levels, subsequently affecting the PgR/ER ratio.