Abstract
Tissue homogenates prepared from rat anococcygeus muscle converted L-arginine to L-citrulline indicating the presence of nitric oxide (NO) synthase. NO synthase activity was also found in crude and partially-purified soluble and particulate fractions prepared from the homogenates. Both soluble and particulate NO synthase were dependent on NADPH, 5,6,7,8-tetrahydrobiopterin and calcium, and inhibited by NG-nitro-L-arginine. Tissue homogenates or crude cytosolic and membrane fractions from rat vas deferens, which does not contain NO releasing non-adrenergic non-cholinergic neurones, had no NO synthase activity.