Steroid Hormone Receptors and Sex Differences in Behavior

This chapter discusses how gonadal steroid hormones contribute to broad sex differences in the behavior of adult animals and the underlying molecular mechanisms that mediate hormone action. During ontogeny, gonadal steroid hormones organize many sex differences that are not manifested behaviorally until sexual maturity is attained. Moreover, these hormones act centrally through their specific receptors in discrete brain regions that are critical for integrating external cues, monitoring internal homeostatic conditions, and executing appropriate behavioral responses. Nuclear steroid hormone receptors are widely distributed throughout regions of the brain critical for the normal display of adult sexual behavior in both males and females. These receptors rely on a complex suite of intracellular regulatory proteins that dictate whether the hormone will have an inhibitory or stimulatory effect on subsequent gene transcription. The chapter highlights how the field of neuroendocrinology has substantially advanced the understanding of how the neonatal steroid hormone environment contributes at the molecular, cellular, and behavioral levels to define gender-specific differences.