title: [The role of hormones in the sex differentiation of the central nervous system in animal and man. Critical study].
abstract: According with experiments, it appears that hormonal environment plays a major role on anatomical, neuroendocrinological and behavioral sexual differentiation in animals. This environment occurs at a critical period, which is specific for each specie, either during fetal life or soon after birth. Sexually dimorphic behavior appears to be influenced by androgens who act either directly or after chemical modification on specific central receptors. In the absence of androgens during the critical specific period, these central structures and consequent behavior differentiate in a feminine pattern. In the presence of androgens during this period, structures and behavior differentiate in a masculine pattern. But this influence of androgens require a double component, defeminization and masculinization, variable among species, as it is observed in rats and mice when defeminization can not be obtained in primates. In human beings, "nature experiments" such as congenital adrenal hyperplasia in feminine foetuses and abnormalities in testosterone metabolism in masculine foetuses are more difficult to study. Fetal hyperandrogenization is responsible of an anatomical and perhaps behavioral masculinization. Neuroendocrine and behavioral defeminization seems not to occur as ovulatory menstrual cycles are possible with a regular treatment, and as sexual identity is feminine when sex of rearing is feminine even if some aspects of sexual roles are unusual. Moreover, these peculiar behavioral traits and changes in sexual orientation in a masculine way at puberty are difficult to explain : fetal hyperandrogenization seems to play a role, as it is observed in animals and as seem to demonstrate Dr J. Imperato-Mc Ginley's observations, but other factors seem to predominate, such as parental attitude in regard with sexual ambiguity and psychological consequences of the acknowledgment of ambiguous genitalia.
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000503:physiopathology; D013734:Androgen-Insensitivity Syndrome / Q000503:physiopathology; D000728:Androgens / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002490:Central Nervous System / Q000254:growth & development*; D012734:Disorders of Sex Development / Q000503:physiopathology; D004958:Estradiol / Q000502:physiology; D005260:Female; D005783:Gender Identity; D006801:Humans; D008297:Male; D011247:Pregnancy; D051381:Rats; D011944:Receptors, Androgen / Q000502:physiology; D011960:Receptors, Estrogen / Q000502:physiology; D012733:Sex Differentiation; D012726:Sexual Behavior, Animal / Q000502:physiology; D013739:Testosterone / Q000502:physiology
chemical_list: D000728:Androgens; D011944:Receptors, Androgen; D011960:Receptors, Estrogen; D013739:Testosterone; D004958:Estradiol
vernacular_title: Role des hormones dans la différenciation sexuelle du système nerveux central chez l'animal et chez l'homme. Etude critique.