Role of prostaglandins in the renal response to calcium infusion.
The effects of intrarenal infusions of calcium gluconate (10 and 100 micrograms Ca.kg-1.min-1) on renal hemodynamics and on renal excretory function were studied in anesthetized mongrel dogs. In one group, the two doses of calcium were infused for 30 min each (1 ml/min). In a second group, the same doses were administered 30 min after the start of an infusion of prostaglandin (PG) inhibitors (intrarenal indomethacin, 10 micrograms.kg-1.min-1, or intravenous bolus injection of meclofenamate, 5 mg/kg). No change with physiological significance was observed during the infusion of 10 micrograms Ca.kg-1.min-1. However, the infusion of 100 micrograms Ca.kg-1.min-1 induced increases (P less than 0.05) in glomerular filtration rate (50%), sodium excretion rate (180%), and fractional excretion of sodium (160%), with respect to control precalcium values. All these changes were prevented by the concurrent administration of PG synthesis inhibitors. Urinary PGE2 and 6-keto-PGF1 alpha increased 220 and 85%, respectively, during the infusion of 100 micrograms Ca.kg-1.min-1, but both decreased (P less than 0.05) below basal levels during the concurrent administration of PG synthesis inhibitors. The infusion of 100 micrograms Ca.kg-1.min-1 decreased (P less than 0.05) renal blood flow by 16% during the administration of PG synthesis inhibitors. These results suggest that PGs are mediating the increase in hemodynamic and excretory factors induced by the intrarenal infusion of 100 micrograms Ca.kg-1.min-1.
Lahera
V
V
Department of Physiology and Biophysics, Mayo Clinic, Rochester, Minnesota 55905.
Fiksen-Olsen
M J
MJ
Romero
J C
JC
D015121:6-Ketoprostaglandin F1 alpha / Q000652:urine; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D015232:Dinoprostone / Q000652:urine; D004285:Dogs; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D007213:Indomethacin / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008469:Meclofenamic Acid / Q000494:pharmacology; D011453:Prostaglandins / Q000502:physiology*; D012079:Renal Circulation / Q000187:drug effects
D011453:Prostaglandins; D008469:Meclofenamic Acid; D015121:6-Ketoprostaglandin F1 alpha; D015232:Dinoprostone; D002118:Calcium; D007213:Indomethacin