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.

Molybdate and the molecular properties of the vervet monkey estrogen receptor.

The Vervet monkey (Cercopithecus aethiops pygerythrus) uterine estrogen receptor was partially characterised. The effect of the molybdate oxyanion on various molecular properties of the receptor was investigated. Molybdate appeared to affect the subunit structure and apparent heterogeneity of the receptor. Anion exchange chromatography of uterine cytosols yielded two ligand binding subunits in a 1:1 ratio in the absence of sodium molybdate, while only a single labelled complex could be demonstrated in cytosols prepared in molybdate containing buffers. Chromatofocussing of the nonstabilized cytosols revealed substantial receptor heterogeneity (7 peaks) while a much simpler pattern (2 peaks) could be observed in the presence of the molybdate. Likewise, iso-electric focussing of labelled cytosols on agarose gels yielded at least 3 high affinity binding components (pI:6.8, 6.2, 5.9) in the absence and only one major band in the presence of sodium molybdate (pI 5.9).