Calcium (Ca) Mediated Phosphate (PO4) Transport in the Proximal Convoluted Tubule (PCT) of the Rabbit
Several clearance studies have suggested a direct effect of calcium (Ca) on phosphate (PO4) handling by the kidney. Micropuncture studies by Amiel and colleagues1 have shown enhancement of fractional phosphate reabsorption in the proximal convoluted tubule when plasma calcium was raised from low towards normal values in parathyroidectomized rats. Conversely, Goldfarb et al 2 have shown a decline in fractional phosphate reabsorption in this portion of the nephron with the induction of mild hypercalcemia in thyroparathyroidectomized dogs. The divergence of these results may be due to species differences, the level of plasma phosphate or ionized calcium before and after calcium chloride administration, or the other various indirect effects of calcium on phosphate handling by the nephron.
KeywordsProximal Convoluted Tubule Tubule Segment Phosphate Reabsorption Plasma Phosphate Micropuncture Study
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