Male and Female Sexual Responses in Male Rats Given Estradiol Benzoate and 5α-Androstan-17β-ol-3-one Propionate

Abstract

Varying doses of estradiol benzoate (EB) were injected systemically into sexually experienced, castrated, male rats. The daily EB injections were given in combination with dihydrotestosterone propionate (DHTP, 125 µg/rat/ day). This dose of DHTP is, by itself, ineffective in activating male behavior, but effective in stimulating growth of penile “spines.” At dose levels of 0.5 ng or 10 µg/rat, EB activated mounting with thrusting and intromission. At 167 ng/rat, EB activated the complete male copulatory pattern, including ejaculation. In addition to displaying male behavior, the EB plus DHTP-treated rats displayed lordosis. Percentages of animals showing lordosis were 50, 86 and 93 for the 0.5, 10 and 167 µg EB dosage groups, respectively. Testosterone propionate (TP, 150 µg/day/rat) administered in combination with DHTP (125 µg/ rat/day) activated complete male copulatory patterns in castrated males, but only 9% of such males displayed lordosis. Additionally, 0 of 20 intact, untreated males displayed lordosis. This experiment demonstrates that EB can activate complete male sexual behavior in males possessing adequate penile histology. However, it does not prove that aromatization of androgens is a prerequisite for display of such behavior in normal, intact rats. (Endocrinology94: 136, 1974)