The effect of hypocalcemia on renal bicarbonate absorption.
The effect of hypocalcemia on renal bicarbonate absorption (RHCO3/GFR) was examined in bicarbonate-loaded dogs. Following the infusion of ethylene-bis(oxyethylenitrilo)tetraacetic acid (EGTA) in intact dogs, RHCO3/GFR fell from 23.8 +/- 0.7 to 20.8 +/- 0.6 (p less than 0.005) and in thyroparathyroidectomized (TPTX) dogs from 25.6 +/- 1.44 to 23.6 +/- 2.15 (p less than 0.025). By contrast, infusion of EGTA which had been titrated with calcium had no effect, RHCO3/GFR being 27.7 +/- 1.14, control and 28.5 +/- 0.38, during EGTA (p less than 0.05). Hypocalcemia also significantly depressed the renal absorption of phosphate. There were no effects on renal hemodynamics or electrolyte excretion. These studies suggest that plasma-ionized calcium may play a role in regulating renal bicarbonate and phosphate absorption.
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D004285:Dogs; D004533:Egtazic Acid / Q000494:pharmacology; D005260:Female; D006996:Hypocalcemia / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D010280:Parathyroid Glands / Q000502:physiology; D010710:Phosphates / Q000378:metabolism; D013961:Thyroid Gland / Q000502:physiology
D001639:Bicarbonates; D010710:Phosphates; D004533:Egtazic Acid; D002118:Calcium