Dehydroepiandrosterone regulates insulin-like growth factor-1 system in adult rat hypothalamus

Dehydroepiandrosterone (DHEA) and its sulfate ester (DHEA-S) exert multiple effects in rodent and human brain. Several findings suggest that insulin-like growth factor-1 (IGF-1) is involved in the actions of DHEA. In this study, we assessed whether systemic administration of DHEA regulates the IGF-1 system in the hypothalamus, hippocampus, cerebral cortex, and cerebellum of adult rats. DHEA resulted in a significant reduction in IGF-1 receptor protein levels. This effect was dose dependent and restricted to the hypothalamus. In contrast to IGF-1 receptor, IGF-1-binding protein 2 levels were unaffected by DHEA treatment. IGF-1 levels were significantly increased in the hypothalamus of the rats treated with DHEA, whereas IGF-1 serum levels were not affected by DHEA. The effects of DHEA on the hypothalamic IGF-1 system may be highly relevant to the control and maintenance of hypothalamic neuroendocrine function.