Purification and Characterization of Nitric Oxide Synthase-Activating Factor.

A factor activating brain nitric oxide synthase was detected in rat urine and partially purified by reversed-phase high-performance liquid chromatography (HPLC). Its intracerebroventricular injection reduced the blood pressure and heart rate of rats. A similar activating factor was detected in rat brain, heart, kidney, liver, and the adrenal. Since its activity per wet weight was the highest in the adrenal, we decided to purify it from bovine adrenals and obtained a partially purified preparation by FPLC MonoQ column chromatography. The active fraction stimulated cyclic GMP (cGMP) production in primary cultures of neuronal cells from fetal rat brain. These results suggest that an activator of nitric oxide synthase is present in bovine adrenals as well as in the urine and various tissues of rats. This factor showed hypotensive and bradycardiac actions when injected into the brain.