Molecular Mechanisms of Steroid Hormone Actions in the Brain

Abstract

As evidenced by the diversity and comprehensiveness of the other chapters in this book, the hypothesis that endogenous and exogenous steroid hormones can have direct effects on neurons in specific regions of the brain that may in turn precipitate and/or regulate the expression of aggressive behaviors is now widely accepted, even though we still know surprisingly little about the molecular mechanisms of these hormone actions. This paucity of information is striking in view of the long history of experimental behavioral neuroendocrinology dating back for literally thousands of years, to when castration was first used to curb sexual and aggressive behaviors in man and other animals (see Luttge, 1971). Over a century ago, Berthold (1849/1944) was the first to report that castration and subsequent testis transplantation could reversibly inhibit sexual, aggressive, and crowing behaviors in roosters, thus setting the pattern for future studies on the endocrine bases of these and other behaviors in many species. The present chapter reviews recent literature on the molecular mechanisms of estrogen, progestin, androgen, and glucocorticoid hormone actions in the mammalian brain. Each of these classes of steroids has been shown to influence the display of agonistic behaviors in mammals. No attempt will be made to relate the biochemical and behavioral actions of these steroids, because this material is reviewed in other chapters in this book.