PROGESTERONE AND ITS METABOLITES IN THE F UNCTIONS OF THE CENTRAL-NERVOUS-SYSTEM

Progesterone (P-4) and its metabolites are involved in several functio ns of the central nervous system (CNS). These steroids participate in neuronal excitability, reproduction and sexual behavior. P-4 and its m etabolites exert their effects on neurons and glial cells through seve ral mechanisms that include the interaction of the steroids with: 1) i ntracellular specific receptors; 2) modulatory sites located in neurot ransmitter receptors; and 3) ionic channels. By these mechanisms, modi fications in gene expression, second messengers' production and ion co nductance are induced. The activities of the P-4 metabolites have been mainly related to membrane effects, whereas for P-4, the transcriptio nal and translational effects are mediated by intracellular receptors. Thus, these steroids can modify the CNS functions at short (milliseco nds), medium (minutes) or long term (hours or days) lapses. The knowle dge of the molecular mechanisms involved in the actions of P-4 and its metabolites in the CNS will contribute to the understanding of fundam ental biological processes such as sexual behavior and reproduction, a nd it will open the possibility of alternative therapies in the treatm ent of some neurologic and psychiatric disorders such as epilepsy, anx iety, premenstrual syndrome, and cerebral tumors which possess hormona l regulation.