Dehydroepiandrosterone (DHEA) decreases open-field spontaneous activity of Zucker rats

The behavioral endpoint of open-field spontaneous activity was used to characterize further the central nervous system actions of dehydroepiandrosterone. DHEA, administered by intraperitoneal injection, causes a dose-dependent decrease in the spontaneous activity of lean and obese Zucker rats when exposed to a novel environment. The midpoint of DHEA's effect is around 50 mg/kg, a dose similar to that which reduces caloric intake of the rat by nearly 50%. d-Fenfluramine, a known anorectic agent, decreases spontaneous activity under the same conditions. Administration of either DHEA or d-fenfluramine leads to changes in serotonin or its metabolite, 5-hydroxyindole acetic acid, in select regions of the brain. These results emphasize that DHEA given peripherally can affect both the level of neurotransimitters and central nervous system function.