Neuroendocrinology of Male Reproductive Behavior

Abstract:

Berthold, working in the mid-nineteenth century, first published data linking the endocrine secretions of the rooster testes to the display of masculine courtship behavior. Since then hundreds of experiments have been published showing that testosterone is the endocrine signal produced by the Leydig cells of the testes, which in male mammals contributes both to the activation of mating behavior in adulthood and to the organization during perinatal life of neural mechanisms that control this behavior. The broader topic of the neural basis of male sex behavior has recently been reviewed (Hull et al., 2002). Therefore, the present review will concentrate selectively on neuroendocrine variables that control the adult activation as well as the perinatal development of brain mechanisms controlling male-typical sexual motivation, courtship, penile erection, and coital behaviors, with an emphasis on common mammalian models including the rat, mouse, hamster, ferret, and monkey. A common theme to all of these studies is that testosterone exerts its actions in the neural systems controlling male-typical sexual behavior both by acting directly via neural androgen receptors and after neural aromatization to estradiol or 5α−reduction to dihydrotestosterone. Estradiol, in turn, affects neural morphology and function via estradiol receptors of the alpha- or beta-subtypes, whereas dihydrotestosterone, like testosterone, acts via androgen receptors. The evidence reviewed indicates that there are many similarities and a few differences among mammalian species, including higher primates, in the principles of neuroendocrine regulation that control the development and expression of male sexual behavior.