Clinical implications of circulating neurosteroids

Neurosteroids' effects and mechanisms for social, cognitive, emotional, and physical functions

Hormones are trophic factors that integrate central and peripheral nervous system functions, and can influence social, cognitive, emotional and physical (SCEP) processes. Greater understanding of behavioral and neurobiological underpinnings of mental, cognitive, and/or physical changes with maturation is becoming increasingly important as the world's population ages. There are individual differences in how people age, but the factors that influence these differences are not well understood. Social supports are one factor that may influence the trajectory of age-related processes. The loss of close relationships, especially among older persons, is one of the greatest risk factors for mental and physical decline. Progesterone, secreted by the ovaries, or produced de novo in the brain, is readily converted centrally to 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), and can influence SCEP, through rapid, non-classical steroid-mediated actions. Our hypothesis is that 3alpha,5alpha-THP is a key trophic factor in SCEP and development. Our research has demonstrated that 3alpha,5alpha-THP facilitates social and sexual behavior of rodents, which evokes further increases in 3alpha,5alpha-THP in midbrain and hippocampus, brain areas involved in SCEP. The role of 3alpha,5alpha-THP to influence social and/or sexual experience, and thereby SCEP, is discussed in this review. Further understanding of these neurobiological and/or behavioral factors may lead to findings that ultimately can promote health and prevent disease.

Neurosteroids and neuroactive drugs in mental disorders

Clinical and preclinical studies have suggested that fluctuations in the peripheral and brain concentrations of progesterone and deoxycorticosterone and its metabolites 3alpha,5alpha-tetrahydroprogesterone and 3alpha,5alpha-tetrahydrodeoxycorticosterone, respectively, might play an important role in certain pathological conditions characterized by emotional or affective disturbances, including major depression, anxiety disorders, and schizophrenia. Moreover, it has been shown that administration of drugs having clinical relevance in the treatment of these pathologies influence the secretion of these steroids. It remains to be determined, however, whether such changes in the concentrations of neuroactive steroids are a cause of, a risk factor for, or a consequence of mental disorders. The observation that effective pharmacological treatment of some of these pathologies influences the concentrations of neuroactive steroids suggests that these endogenous compounds might themselves prove to be efficacious in the treatment of mental illness.