Resumen de Diferenciación sexual: el factor de Jost
Ana María Pascual-Leone Pascual
Sexual differentiation in mammals is a good example of the epigenetic process produced by the interaction between the genome and hormones secreted by the fetal testes: testosterone and anti- Müllerian hormone (AMH). Sexual differentiation takes place in the gonads and brain (hypothalamus) in two branches: neuroendocrine and sexual behavior. Both branches of the cerebral sexual dimorphism can be studied in the rat. The former by the ovulation pattern of an ovary transplanted in the abdominal cavity of male or female rats which are castrated at birth. The latter can be examined by the response of lordosis of female rats with plain sexual differentiation in front of the male. The different brain regions containing estrogen receptors have been localized. Fetal testes regulate gonadal differentiation through two hormones; testosterone an anti-Müllerian hormone. Testosterone differentiates Wolff channels in deferent vessels, epididimus and seminal vesicles, and AMH induces the regression of Müller channels in the genetically male embryo, in which testes are previously differentiated in the last fetal stage of gonad development. In the female, with no testosterone or AMH, the Wolff channels undergo involution and those of Müller spontaneously differentiate to uterus, Fallopian trumps and upper part of vagina. The credit for the knowledge of these matters should be given to Prof. Alfred Jost (Paris, 1947-50), who discovered AMH in rabbit fetuses. Currently, AMH has been endowed with many biological functions, the most important being the involution of Müllerian channels in genetically male fetuses. AMH is a biomarker of diseases such as ovarian tumors and abnormal steroid synthesis in ovary and its finding helped explain a heterogeneous number of sexual-related pathologies. AMH gene has been cloned and anti-AMH monoclonal antibodies obtained. Since AMH has been associated with the transforming- growth factor beta (TGF-ß) family, whose members are involved in cancer processes, its biological functions and potential therapeutic applications are currently and will certainly be subject of intense studies.
