The brain: a vulnerable target.

Abstract

This article addresses the description of several endocrine-related functions of the brain. It has emerged that steroids and growth factors may influence brain functions, and that brain cells may metabolize sex steroids. The crosstalk between different types of brain cells (neurons, astrocytes, the LHRH (luteinizing hormone-releasing hormone) producing GT1 cell line, etc.) has been described. Of relevance is that brain enzymes may convert sex steroids into compounds able to bind the GABAa receptor, creating a link between brain steroids and one neurotransmitter system. The data presented also provide the first demonstration that glial-neuronal interactions may intervene, in conjunction with neuronal-neuronal communications, in the control of the secretion of hypothalamic hormones. The detailed discussion of all these mechanisms has provided a long list of possible targets during the aging process. Fortunately, the demonstration that stem cells may be rescued in the "adult" CNS by the proper manipulations with growth factors opens new hope and directions for future interventions.