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.
Lahera
V
V
Department of Physiology and Biophysics, Mayo Clinic, Rochester, MN 55905.
Fiksen-Olsen
M J
MJ
Romero
J C
JC
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