Effect of saline infusion on net reabsorption of endogenous sulfate relative to that of phosphate in intact and thyroparathyroidectomized rats.

Clearance experiments have been performed to study the effects of saline infusion on the reabsorption of inorganic sulfate (SO4) at endogenous levels. Adult female Sprague-Dawley rats on a standard diet were used. Both intact and thyroparathyroidectomized (TPTX) animals were infused with a 130 mmol/l sodium chloride solution at a low (0.15 ml/min) and a high (0.375 ml/min) rate. This increase of the infusion rate decreased the reabsorption of SO4 in both groups of animals significantly. The fractional excretion of SO4 in the intact rats increased from 9.9 +/- 5.6 to 18.4 +/- 3.6% (mean values +/- SD, p less than 0.001) and in the TPTX rats from 5.3 +/- 2.5 to 22.4 +/- 6.3% (p less than 0.001). It is concluded that endogenous parathyroid hormone has no major effect on the saline-induced inhibition of reabsorption of SO4.