Minireview: Role of glia in neuroendocrine function.

Long relegated to the backwaters of neuroendocrinology, it is becoming increasingly apparent that glial cells of the central and peripheral nervous system are key participants because they are capable of both sending and receiving hormonal signals. Hormones are also a critical component of neuronal/glial cross talk, leading to neuromodulatory and neurotrophic actions under physiological and pathological conditions. In the peripheral nervous system, hormonal actions on Schwann cells and hormonal metabolites produced by these glial cells promote myelin formation and the remyelination and regeneration of injured nerves. In the central nervous system, glial cells participate in the hormonal regulation of synaptic function, synaptic plasticity, myelin formation, cognition, sleep, and the response of nervous tissue to injury. In addition, central glial cells participate in the regulation of hormonal secretion by hypothalamic neurons. Therefore, glial cells are a key element to understanding hormonal actions in the nervous system and the regulation of neuroendocrine events.