Determination of nitric oxide synthase activity in rat, pig and rabbit prostate glands

The conversion of L-arginine to L-citrulline by nitric oxide synthase and other enzymes was studied in rat, pig and rabbit prostate glands by incubating preparations of the glands with [H-3]L-arginine and measuring [H-3]L-citrulline formation. The nitric oxide synthase inhibitor N-G-nitro-L-arginine, (100 mu M) reduced [H-3]L-citrulline production in preparations from ail three species. The arginase inhibitor L-valine (60 mM) inhibited [H-3]L-citrulline production in rat and pig but not in rabbit prostate preparations. Omission of calcium or NADPH significantly reduced nitric oxide synthase-like activity in preparations from all three species but arginase-like activity was not significantly affected. The results indicate that the rabbit prostate contains the greatest amount of calcium-dependent nitric oxide synthase activity, the rat and pig prostates also have arginase-like enzymatic activity and the rat prostate contains an additional unidentified enzyme that converts L-arginine to L-citrulline. (C) 1997 Elsevier Science B.V.