Relationship of renal prostaglandins to distal transport of sodium chloride in normokalemic and hypokalemic man.

The relationship between renal prostaglandins (PG) and electrolyte transport in the thick ascending limb of Henle's loop (TALH) was examined in 8 normal subjects and in 7 patients with hypokalemia, the latter including 4 cases of Bartter's syndrome. Distal fractional delivery and distal reabsorption of chloride and sodium were determined using clearance techniques under maximal volume expansion, and urinary excretion rates of PGE2 and PGF2 alpha were measured. In the normal subjects, suppression of PG synthesis by indomethacin decreased distal delivery without changing distal reabsorption, suggesting that PG may influence solute transport at a site proximal to the diluting segment. In the subjects with Bartter's syndrome, however, distal reabsorption was impaired, this defect being apparently independent of PG as it was unaffected by inhibition of PG synthesis. In the patients with hypokalemia due to non-renal causes, distal reabsorption of chloride was increased, resulting in a decreased chloride clearance. These results suggest a link between renal PG and solute transport in normal man and also provide evidence that Bartter's syndrome is characterized by a prostaglandin-independent defect in distal reabsorption which is not found in hypokalemia due to other causes.