Stimulation of renin release by intrarenal calcium infusion.
The effects of intrarenal infusions of calcium gluconate (10 and 100 micrograms Ca/kg/min) on renin secretion were studied in anesthetized mongrel dogs. In one group, the two doses of calcium were infused for 30 minutes each (1 ml/min). In a second group, the same doses were administered 30 minutes after the start of infusion of prostaglandin synthesis inhibitors (indomethacin 10 micrograms/kg/min intrarenal or injection of meclofenamate 5 mg/kg i.v. bolus). Mean arterial pressure, renal blood flow, and glomerular filtration rate remained unchanged during the infusion of calcium in both groups. The infusion of 10 micrograms Ca/kg/min increased renin secretion 77% and sodium excretion 123%. During the infusion of 100 micrograms Ca/kg/min, renin secretion was not different from precalcium values, whereas urinary 6-keto-PGF1 alpha, urine flow, sodium, potassium, and calcium excretion rates were increased (p less than 0.05). During the administration of prostaglandin synthesis inhibitors, the urinary 6-keto-PGF1 alpha levels were reduced, and the infusion of 10 micrograms Ca/kg/min failed to increase renin secretion, sodium excretion, or 6-keto-PGF1 alpha excretion rates. The infusion of 100 micrograms Ca/kg/min during prostaglandin synthesis inhibition did not modify urine flow or sodium excretion; however, potassium and calcium excretions increased. It is concluded that 1) the intrarenal infusion of small doses of calcium gluconate is capable of stimulating renin secretion through a prostaglandin-mediated mechanism, and 2) the stimulation of renin secretion as well as the increase in sodium excretion induced by calcium are independent of hemodynamic alterations.
Department of Physiology and Biophysics, Mayo Clinic, Rochester, MN 55905.
V
V
Lahera
M J
MJ
Fiksen-Olsen
J C
JC
Romero
D015121:6-Ketoprostaglandin F1 alpha / Q000652:urine; D000803:Angiotensin I / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000652:urine; D002125:Calcium Gluconate / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D005942:Gluconates / Q000494:pharmacology*; D007269:Injections, Intra-Arterial; D007668:Kidney / Q000502:physiology*; D008297:Male; D009318:Natriuresis / Q000187:drug effects; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D012077:Renal Artery; D012079:Renal Circulation / Q000187:drug effects; D012083:Renin / Q000378:metabolism*
D005942:Gluconates; D011448:Prostaglandin Antagonists; D015121:6-Ketoprostaglandin F1 alpha; D000803:Angiotensin I; D012083:Renin; D002125:Calcium Gluconate; D002118:Calcium