Intracerebroventricular ANP(1-28) has no obvious effects on renal blood flow and function in conscious sheep

1. The study examines whether intracerebroventricular (ICV) infusion of atrial natriuretic peptide (human ANP,1-28) influences renal electrolyte and water excretion, vasopressin release, renal and femoral blood flows in conscious ewes. The blood flow was measured by chronically implanted ultrasonic flow probes. 2. ICV infusion of ANP(1-28) at 25 pmol/min for 60 min did not affect renal Na and K excretion or plasma vasopressin levels. In two out of six animals a mild water diuresis developed at about 50 min post-infusion. 3. The plasma osmolality, Na, K and protein concentrations did not change during the experiments. 4. The renal and femoral arterial blood flows were not influenced by 30 min ICV infusions of ANP(1-28) at 25 and 85 pmol/min. 5. It is concluded that human ANP(1-28) has no, or negligible, effects on renal function, femoral and renal blood flow when given ICV in amounts obviously elevating cerebrospinal fluid levels far above normal.