DIVALPROEX SODIUM ATTENUATES GROWTH-HORMONE RESPONSE TO BACLOFEN IN HEALTHY-HUMAN MALES

The effect of divalproex sodium (DVP) on gamma-aminobutyric acid-B (GA BA(B)) receptor function in humans was assessed by measuring growth ho rmone (GH) responses to a challenge with a GAGA(B) receptor agonist, b aclofen, in 10 male healthy volunteers. Each subject received 20 mg of baclofen at 10:00 A.M., and blood samples were collected for measurin g GH before and 30, 60, 90, 120, 150, 180 min after baclofen administr ation. The baclofen challenge test was repeated after 1 week of treatm ent with DVP (1000 mg/day). The results showed that the plasma GH resp onse to baclofen was significantly attenuated by the DVP treatment and that the degree of attenuation was positively correlated with the blo od levels of valproic acid. Our findings suggest that DVP downregulate s hypothalamic GABA(B) receptor function in humans.