PROSTATIC CANCER/BENIGN PROSTATIC HYPERTROPHY. SUBCELLULAR DISTRIBUTION OF ESTRADIOL/ANDROGEN RECEPTORS

Hormone catalysis: role of protecting and modifying reagents of sulfhydryl groups on estrogen receptor in breast cancer

We have studied the modulation and differential sensitivity of the estrogen receptor (ER) in breast cancer in the presence of protecting or modifying agents of disulfide bonds and sulfhydryl groups present in the ER steroid-binding domain. Protecting agents such as mercaptoethanol and dithiotreitol increased the [(3)H]estradiol binding to ER by 25% and 50%, respectively. Modifying agents such as p-chloromercuribenzensulfonate decreased the [(3)H]estradiol binding by 70% and this was nearly completely abolished by N-ethylmaleimide (94%). These data indicate that disulfide bonds and sulfhydryl groups in the steroid-binding domain are intimately involved in the maintenance of a receptor structure necessary for estradiol binding.

The role of progesterone in endometrial estradiol- and progesterone-receptor synthesis in women with menstrual disorders and habitual abortion

The objective of this comparative study was to determine the influence of changes in estradiol and progesterone during ovulatory vs. anovulatory cycles on levels of estradiol receptor (ER) and progesterone receptor (PgR) in endometrium. Thirty women (range age 20-35 years) were divided into three groups: women with a history of habitual abortion, obese women with menstrual disorders, and women with regular ovulatory cycles as well as proven fertility. A single venous blood sample and an endometrial sample were simultaneously obtained during the secretory phase of the menstrual cycle, in order to measure estradiol and progesterone levels and ER and PgR concentrations in cytosol and salt-extracted nucleosol. Plasma estradiol levels were not different between groups. Plasma progesterone was two times higher in fertile women than in habitual aborters. In endometrial tissue, progesterone content was 200 times higher in fertile women than in habitual aborters. ER and PgR were lower in the cytosol than in the nuclear fraction in fertile and obese women. Both receptors were at their lowest level in the cytosol and nuclear compartment of women with recurrent miscarriage. Fluctuations mainly in the sex hormone progesterone, in plasma and endometrium tissue, could interfere with ER and PgR levels.