[Influence of anabolic agents on behavior].

Abstract

Sexual steroids are involved not only in the triggering of sexual activity but also in sex-linked social behaviour (aggressiveness etc.) The use of anabolic agents (particularly steroids) raises the problem of their possible interference with these mechanisms. In the normal male, an injection of androgen does not alter the level of sexual activity, which seems to be determined by nervous mechanisms. On the contrary, by feed-back in the hypothalamo-hypophysial mechanisms it exerts a depressive effect on the endogenous secretion. Female hormones have an inhibiting effect which works both by reducing the actual secretion of androgen and by direct action at two levels: the nervous receptors and the target organs of the genital apparatus. In the female, injections of exogenous hormones may interfere with the mechanisms regulating the oestrous cycle, e.g. inhibition of oestrous and of ovulation by progestagens, and luteotrophic or luteolytic action in the case of the estrogens. In an ovariectomized female the injection of testosterone propionate causes the appearance of sexual receptivity. The behaviour induced in this way is completely normal and free from any abnormal male component. The importance of this action has led to the presumption of a role played by the androgens in the normal triggering off of female sexual behaviour. It therefore seems that the nervous system of the female, but not of the male, possesses a potential bisexuality. The rate at which the hormone passes into the circulation appears to be more important than the actual type of hormone (estrogen or androgen) in causing the appearance in the female of sexual behaviour of one or the other sex. It has been suggested that estrogens might be the active steroid form necessary at the nervous structure level for initiating sexual behaviour in the two sexes, while the androgens would have to undergo aromatization in order to acquire their effectiveness at that level. Aggressiveness depends on the sexual hormones; the androgens are normally responsible for the high level of aggressiveness in males. On the other hand, in some species the characteristic aggressiveness of the female is explained by the presence of progesterone (e.g. hamsters). The territorial marking typical of the male of, for example, the dog, cat and rabbit species etc. is also due to the androgens. The pheromones usually depend on the sexual hormones (pheromones of sexual attraction which promote or inhibit aggression, etc.) A "sexualization" of the nervous system exists---e.g. of the hypothalamus---which is refelcted not only in the modes of hypophysial secretion but also in the type of sexual behaviour. This sexualization occurs through the loss of the possibility of a female-type reaction that occurs in the male under the influence of the androgenic secretions of the foetal or neonatal testicle. Therefore this action appears at an early stage and is conclusive...