Steroid hormones use non-genomic mechanisms to control brain functions andbehaviors: A review of evidence

Progestins, estrogens, androgens, and corticosteroids are capable of modify ing brain functions and behaviors by mechanisms that involve the classic ge nomic model for steroid action. However, experimental evidence indicates th at some responses to steroid hormones use non-classical, non-genomic mechan isms, This paper reviews the evidence that steroids can bind to receptors i n the plasma membrane, activate cell signaling pathways, and regulate respo nses on a time scale of seconds or a few minutes. The existence of these al ternative regulatory pathways for steroid hormones should make endocrinolog ists and neurobiologists change how they think about steroid hormones. It i s no longer valid to assume that minute-to-minute changes in steroid concen trations are not regulating biologically important, short-term responses, o r that the only steroids with biological functions are the ones that bind w ith high affinity to intracellular steroid receptors.