THE EFFECT OF TESTOSTERONE OR OESTRADIOL UPON THE SEXUAL AND ASSOCIATED BEHAVIOUR OF THE ADULT FEMALE RHESUS MONKEY

Abstract

SUMMARY The effect on sexual behaviour of testosterone propionate (1, 5 or 25 mg./day) or oestradiol monobenzoate (50 μg./day) administered to ovariectomized female rhesus monkeys was studied in the laboratory in six females and three males. One milligram testosterone increased the frequency with which the females 'presented' to the males—that is, invited them to mount. But the proportion of these presentations effective in stimulating the male, and the males' sexual activity, remained low. Oestradiol had a similar, but lesser, effect on the females' behaviour but resulted in marked stimulation of the males' mounting activity, and increased the sexual response of the males to the females' sexual presentations. Larger doses of testosterone had a decreasing effect upon the females' presentations, but increased their aggression towards the males; some females became progressively less receptive to the males' attempts to mount. The effects of these hormones on behaviour and on the females' vaginal smears, sexual skins and clitorides were compared. These studies did not finally establish the site of action of administered hormone, but suggested that testosterone may have stimulated the females' receptivity by an action mainly on their central nervous systems, whereas oestrogen increased their sexual attractiveness to the male principally by an action on their genitalia.