Androgens stimulate preoptic area Na+,K+-ATPase activity in male rats.

This paper describes the effects of castration and testosterone replacement on the Na+,K+-ATPase activity levels of the cerebral cortex (CC), preoptic-suprachiasmatic region (POSC) and mediobasal hypothalamus (MBH) in male rats. Na+,K+-ATPase activity was estimated as the ouabain-sensitive fraction of ADP and AMP generation rate, measured by high-pressure liquid chromatography (HPLC) with UV detection, from a standard incubation mixture containing 3 mM ATP. Orchidectomy, performed 4 weeks before sacrifice, decreased ATPase activity of MBH. Testosterone propionate treatment (50 micrograms/day X 2 days) to castrated animals resulted in a 4-fold increase in enzyme activity in the POSC, an effect that might be related to the behavioral effects of androgens. None of the treatments seemed to influence the enzyme activity of the cerebral cortex.