Regional and subcellular localization of [3H]dihydrotestosterone in brain and pituitary of male mice

Genetic variation in hypothalamic methyltrienolone (R1881) binding in male mice

Methyltrienolone (R1881) binding to androgen receptors (AR) from combined hypothalamic-preoptic-septal cytosol was examined in CF-1, CFW, and CD-1 male mice, strains that differ in their sensitivity to the aggression-promoting property of this hormone. Both the affinity of R1881-AR binding and the number of binding sites (Bmax) significantly differed among the genotypes. The dissociation constant (Kd) was lower in CF-1 males (6.7 nM), a behaviorally responsive strain, in comparison to the insensitive CFW and CD-1 males (3.0 nM and 2.0 nM, respectively). The number of binding sites was higher in CF-1 and CFW males (9.07 and 8.81 fmol/mg protein, respectively) than in CD-1 males (5.11 fmol). The results were basically consistent with studies of neural dihydrotestosterone (DHT) binding in these genotypes, and the implications and limits of these data for understanding the androgenic regulation of intermale aggression are discussed.

Estrogen-induced sexual receptivity and localization of 3H-estradiol in brains of female mice: effects of 5 alpha-reduced androgens, progestins and cyproterone acetate

Sexual receptivity induced in ovariectomized CD-1 mice with chronic daily administration of estradiol benzoate (E2 B) was blocked by concurrent administration of the 5 alpha-reduced androgen, dihydrotestosterone (DHT). Receptivity was restored in these females with progesterone-, but not with dihydroprogesterone-priming 6 hr prior to testing. Delaying the DHT injections until 12 hr after the E2 B injections greatly reduced its inhibitory properties. Receptivity in E2 B-primed females was also blocked by concurrent treatment with cyproterone acetate and 3 alpha-, but not 3 beta-adrostanediol. Pretreatment with DHT, or 3 alpha- or 3 beta-androstanediol failed to consistently affects 3H-estradiol accumulation in crude nuclear and supernatant fractions from brain and pituitary.