Effects of atrial natriuretic peptide on urinary kallikrein excretion and renal function in rats

We investigated whether the renal kallikrein-kinin system is involved in the renal effects of atrial natriuretic peptide (ANP) by measuring the glomerular filtration rate (GFR), urine volume (UV) and urinary excretion of sodium (UNaV) and kallikrein (UkkV) in 4 groups of 10 anesthetized rats before and during (two 10 min periods) the i.v. infusion of Ringer solution (control group) or different doses of ANP (0.25, 0.5 and 1 microgram, respectively). The administration of ANP was associated with a marked and significant increase in UV, UNaV, UkkV and GFR. The diuretic and natriuretic responses to ANP were dose-related, while the changes in GFR and UkkV were short-lived and not related to the dose of ANP. There was no relationship between UV or UNaV and UkkV after ANP administration. In contrast, UkkV correlated closely with GFR (r = 0.675, P less than 0.001). These data do not support the hypothesis that the kallikrein-kinin system contributes to the diuretic and natriuretic effects of ANP, but it might be involved in the renal hemodynamic action of this peptide.