Multiple molecular actions for steroids in the regulation of reproductive behaviors

Steroid hormones control brain functions and behaviors by several molecular actions that include the well-known genomic mechanism, in which intracellular steroid receptors regulate gene expression, and mechanisms that involve cell-surface receptors for steroids. Examples of the latter include the steroid modulation of the GABA_A receptor complex and the recently discovered corticosteroid receptor in neuronal membranes from an amphibian (Taricha granulosa). This cortico steroid receptor meets the major criteria for being a bona fide receptor, is neuroanatomically and pharmacologically distinct from intracellular glucocorticoid receptors and seems to be coupled to G proteins. Furthermore, this membrane receptor seems to be physiologically relevant, functioning in the inhibitory pathways that control reproductive behaviors in Taricha.