Metabolic alkalosis has been reported in patients with chronic hypoparathyroidism under conditions of uncontrolled diet and medication intake. Hypoparathyroidism has also been reported to result in increased renal bicarbonate reabsorptive capacity in acutely bicarbonate-loaded dogs. However, the acid-base effects of experimentally induced chronic hypoparathyroidism have not been investigated in any species. Accordingly we investigated the chronic effects of hypoparathyroidism by thyroparathyroidectomy (TPTX) plus thyroxine replacement on renal regulation of plasma acid-base composition under metabolic balance conditions of normal dietary acid load (group I) and alkali load (group II, 9.0 meq/kg HCO3- daily) in dogs ingesting a normal Cl-, high Ca2+ diet throughout study. For groups I and II pre-TPTX: [HCO3-](p), 19.7 ± 1.0, 20.1 ± 0.9 meq/liter. Plasma acid-base composition (days 5-10) was unchanged by TPTX: Δ[HCO3-](p), -0.7 ± 0.4, 0.0 ± 0.2 meq/liter; Δ[H±](p), 0 ± 1, -1 ± 0 neq/liter, NS from control. A reduction in plasma total calcium concentration ([Ca(T)](p) occurred and persisted (group I: [Ca(T)](p), -1.6 ± 0.2 mg/10 ml, P < 0.01, day 1 and -1.2 ± 0.9, days 5-10; group II: -1.4 ± 0.3 mg/100 ml, P < 0.01, day 1 and -2.3 ± 0.4, days 5-10). No significant change in net acid or Cl- excretion occurred following TPTX. Thus, chronic hypoparathyroidism characterized by a chronic reduction in [Ca(T)](p) does not result in significant alterations in renal regulation of plasma acid-base composition in the dog.
|Original language||English (US)|
|Number of pages||7|
|Journal||American Journal of Physiology - Renal Fluid and Electrolyte Physiology|
|State||Published - Jan 1 1981|
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