2 CASES SUGGESTING A ROLE FOR THE L-ARGININE NITRIC-OXIDE PATHWAY IN NEONATAL BLOOD-PRESSURE REGULATION

Endogenous nitric oxide produced from L-arginine is a potent vasodilat or that may be involved in blood pressure regulation. A male infant wi th argininosuccinate lyase deficiency, who could not synthesize L-argi nine, was hypertensive prior to L-arginine replacement. The infusion o f L-arginine resulted in a decrease in blood pressure. A three-fold in crease in the dose of L-arginine further decreased blood pressure. On discontinuing the infusion of L-arginine, the patient's blood pressure increased. A female infant undergoing an L-arginine challenge test ha d a decrease in blood pressure during L-arginine infusion which resolv ed when the L-arginine infusion was discontinued. These two cases sugg est that nitric oxide production from L-arginine may play a role in th e normal regulation of systemic blood pressure.