Dehydroepiandrosterone (DHEA)

DHEA is different from other sex hormone precursors in that it is also a neurosteroid. A neurosteroid is a steroid that accumulates in the nervous system independently of its production in the endocrine glands. This means that DHEA found in the nervous system was not produced by the adrenal glands. DHEA has been found in the brains of humans, rodents, rabbits, monkeys, and dogs in relatively high concentrations. Recent studies have suggested that the hormone acts directly on the brain. Although the hormone itself has been found in the adult brain, the enzyme needed for its production is only found in the brains of fetuses.

Because the enzyme needed for its production is found only in the brains of fetuses, it is thought that the hormone is somehow related to the organization and development of the brain. When DHEA is added to cultures of developing neurons from the brains of mouse embryos, it causes morphological changes such as increasing axon length. These studies suggest that certain developmental neurological disorders may actually be the result of lower than normal concentrations of DHEA in the fetal brain.