Effect of acute and chronic calcium administration on plasma renin.
To evaluate the effect of Ca(++) on renin release, plasma renin activity (PRA) was measured after acute and chronic Ca(++) administration. 1% CaCl(2) was infused into one renal artery of 10 anesthetized dogs (0.3 mg/kg/min). The excreted fraction of filtered calcium (EF(ca++)) and EF(Na+) from the infused kidney were elevated (P < 0.04) during three successive 15-min infusion periods. Serum calcium concentration was significantly elevated (P < 0.001). Creatinine clearance, systemic arterial pressure, and renal blood flow did not change (P > 0.10). Compared to control (45 ng/ml/h+/-5.2 SE), renal venous PRA was suppressed (P < 0.0001) after infusion of Ca(++) for 15, 30, and 45 min (20 ng/ml/h+/-4.6, 16 ng/ml/h+/-4.0, and 13 ng/ml/h+/-2.7, respectively). 15 and 30-min after infusion, PRA did not differ from control (P > 0.20). Chronic Ca(++) loading was achieved in Sprague-Dawley rats by replacing drinking water with 1% CaCl(2) for 17 days. At sacrifice, serum Ca(++), Na(+), and K(+) of controls (n = 12) did not differ (P > 0.60) from Ca(++)-loaded rats (n = 12). Ca(++) excretion (467 mueq/24 h+/-51) was elevated (P < 0.001) compared to controls (85 mueq/24 h+/-12). PRA (8.6 ng/ml/h+/-1.4) and renal renin content of Ca(++)-loaded rats did not differ from controls (P > 0.80). However, after 8 days of sodium deprivation, both PRA and renal renin content of calcium-loaded animals were significantly lower than the respective values in pair-fed controls (P < 0.005). During the period of sodium deprivation, calcium-drinking animals were in greater negative sodium balance than controls (P < 0.005). The data are consistent with the hypothesis that acute and chronic calcium administration inhibit renin secretion.
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002122:Calcium Chloride / Q000008:administration & dosage; D002136:Calcium, Dietary / Q000494:pharmacology; D003404:Creatinine / Q000378:metabolism; D003864:Depression, Chemical; D004285:Dogs; D007263:Infusions, Parenteral; D007668:Kidney / Q000201:enzymology; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D012077:Renal Artery; D012082:Renal Veins; D012083:Renin / Q000032:analysis / Q000097:blood* / Q000378:metabolism; D012964:Sodium / Q000172:deficiency / Q000652:urine
D002136:Calcium, Dietary; D012964:Sodium; D003404:Creatinine; D012083:Renin; D002122:Calcium Chloride; D002118:Calcium