Effect of prostaglandin inhibitors on renal function in the hypothyroid rat

The mechanisms of the abnormal renal tubular handling of sodium and water in hypothyroidism are still unexplained. Since prostaglandins (PG) have been shown to diminish the tubular reabsorption of both sodium and water, this study was undertaken to examine the possibility that the tubular abnormalities observed in hypothyroidism are prostaglandin mediated. Renal clearance studies were performed in rats before and after administration of two prostaglandin synthetase inhibitors. There was no significant difference in the PG-inhibitor induced absolute and percentage decrease of sodium and fluid excretion between the normal and hypothyroid rats during mild volume expansion. This indicates that prostaglandins are not responsible for the increased fractional sodium and water excretion in hypothyroid animals.