ANDROGEN RECEPTOR IN THE HARDERIAN GLANDS OF THE GOLDEN-HAMSTER - CHARACTERIZATION AND THE EFFECTS OF ANDROGEN DEPRIVATION, THE PITUITARY, AND GENDER

The Harderian glands of the golden hamster were found, by a competitiv e binding assay using H-3mibolerone as the ligand, to have a high af finity androgen receptor. In intact male hamsters, this receptor was p resent in both cytosolic and nuclear KCl-extractable fractions. Castra tion or hypophysectomy led to 3- to 5-fold increases in the concentrat ions of cytosolic receptor with decreased dissociation constants. Hypo physectomy with maintenance of prolactin levels (by removal of pituita ries and their implantation either in the sella turcica or under the k idney capsule) had no effect on androgen receptor binding, compared to hypophysectomy alone. Female hamsters had androgen receptor levels wh ich were 2 to 4 times higher than those of intact males. Hypophysectom y led to elevated receptor binding in ovariectomized female hamsters a nd this rise was prevented by maintaining prolactin levels. Binding of H-3mibolerone in male glands was effectively inhibited by 5 alpha-d ihydrotestosterone, whereas the parent molecule, testosterone, require d approximately a 10-fold greater molar excess to achieve the same amo unt of inhibition. Estradiol and progesterone were relatively poor inh ibitors of the observed binding of H-3mibolerone, while dexamethason e was ineffective. Sucrose gradient studies indicated that the Harderi an androgen receptor migrated to the 8S region, as expected for this r eceptor in molybdate-containing gradients. These results indicate that the androgen receptor in the hamster Harderian gland is a 5 alpha-dih ydrotestosterone receptor. (C) 1994 Wiley-Liss, Inc.