Actions of parathyroid hormone are not impaired during chronic metabolic acidosis.
The effect of parathyroid hormone (PTH) on renal excretion of calcium, phosphate, and bicarbonate was studied in acutely thyroparathyroidectomized dogs with metabolic acidosis. Ammonium chloride 10 gm/day for 3 days was given to 15 dogs to induce chronic metabolic acidosis. Clearance results obtained from these experiments showed that infusion of Beckman 1-34 PTH into normal and acidotic dogs resulted in a marked increase in phosphate and bicarbonate excretion, accompanied by a small reduction in calcium excretion and a slight but significant increase in plasma ultrafilterable calcium. Complementing our clearance data, micropuncture results obtained from the proximal and distal tubules of these animals indicated an enhancement of calcium reabsorption in the distal tubule after administration of PTH. Phosphate reabsorption by the proximal and distal tubules was reduced after infusion of PTH in both normal and acidotic dogs. The fraction of bicarbonate reabsorbed in the proximal tubule was reduced after PTH infusion, but the fraction of bicarbonate reabsorbed in the distal tubule remained unchanged. These data suggest that the phosphaturic, the hypocalciuric, and the bicarbonaturic effects of PTH were not impaired during chronic metabolic acidosis.
D000138:Acidosis / Q000139:chemically induced / Q000378:metabolism*; D000818:Animals; D001639:Bicarbonates / Q000097:blood / Q000652:urine; D002118:Calcium / Q000378:metabolism / Q000652:urine; D004285:Dogs; D005260:Female; D005919:Glomerular Filtration Rate; D006400:Hematocrit; D007263:Infusions, Parenteral; D007668:Kidney / Q000187:drug effects; D008297:Male; D010280:Parathyroid Glands / Q000502:physiology; D010281:Parathyroid Hormone / Q000494:pharmacology / Q000502:physiology*; D010710:Phosphates / Q000097:blood / Q000652:urine; D012964:Sodium / Q000378:metabolism
D001639:Bicarbonates; D010281:Parathyroid Hormone; D010710:Phosphates; D012964:Sodium; D002118:Calcium