Failure of NaHCO3 and KHCO3 to inhibit renin in the rat.
To evaluate the contribution of chloride to NaCl- and KCl-induced renin inhibition, renin responses to NaCl or NaHCO3 and to KCl or KHCO3 loading were compared in NaCl-deprived rats. Sodium balance in animals drinking isotonic NaHCO3 and NaCl for 9 days did not differ (P greater than 0.40); K+ balance was less positive in NaHCO3-drinking animals (P less than 0.005). Plasma renin activity (PRA) in NaCl-loaded (16.5 ng/ml per h +/- 4.4 SE), but not in NaHCO3-loaded rats (57.2 +/- 9.8), was lower (P less than 0.005) than in NaCl-deprived controls (44.8 +/- 4.7). Renal renin content (RRC) of NaCl but not of NaHCO3-drinking animals was also decreased (P less than 0.02). Both PRA and RRC of KCl- but not of KHCO3-loaded rats (5 meq K+/10 g diet) were lower (P less than 0.01) than in NaCl-deprived controls. After acute intravenous expansion with isotonic NaCl or NaHCO3, increases of plasma volume and plasma K+ did not differ (P greater than 0.05). However, PRA of NaCl-expanded rats (11.8 +/- 3.8) was lower (P less than 0.05) than in NaHCO3-expanded animals (29.7 +/- 8.5). The failure of NaHCO3 and KHCO3 to inhibit renin suggests a role for chloride in mediating the renin responses to Na+ and K+.
D000136:Acid-Base Equilibrium; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D001693:Biological Transport, Active; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011188:Potassium / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D012083:Renin / Q000097:blood / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology
D001639:Bicarbonates; D012965:Sodium Chloride; D011189:Potassium Chloride; D012964:Sodium; D012083:Renin; D011188:Potassium