Influence of sex and gonadectomy on sex steroid receptors in rat adrenal gland.

Abstract

Abstract The number of androgen (AR) and estrogen receptor (ER) binding sites was quantitated in cytosol fractions from adult intact male and female rats. The apparent equilibrium constants of dissociation were: 0.8 × 10 −9 M for the AR measured with [ 3 H]-R 1881 and 0.6 × 10 −9 M for the ER labelled with [ 3 H]-estradiol. The mean (±SD) number of available binding sites were (fmol/mg cytosol protein): male: AR: 88.6 ± 7.7 ER: 8.5 ± 1.4; female: AR: 23.8 ± 1.6 and ER: 7.6 ± 0.5. Orchidectomy Caused a two-fold increase in the number of available androgen and estrogen binding sites with a clear-cut reduction 10 days after castration. Ovariectomy elicited an unexpected decrease of ER one day after gonadectomy and full recovery of binding sites was found at 10 days. A significant increase in AR was seen 4 days following ovariectomy.