REGULATION OF URINARY PROSTAGLANDINS IN BARTTERS-SYNDROME

Enhanced prostaglandin production, possibly stimulated by hypokalemia, may mediate the manifestations of Bartter's syndrome. To investigate the cause of increased urinary prostaglandin excretion, we measured urinary immunoreactive prostaglandin E (iPGE) during the oral administration of potassium and the parenteral administration of magnesium, and during water restriction and oral water loading in two subjects with Bartter's syndrome. In one patient (Case 1), iPGE was 0.91 μg/day (normal 0.50 ± 0.20 μg/day, SD). Following the administration of indomethacin, 200 mg/day, iPGE, plasma renin activity (PRA), plasma aldosterone and angiotensin pressor sensitivity returned to normal but serum potassium did not. The oral administration of potassium citrate, acetate, bicarbonate, (Potassium Triplex), 240 meq/day for four days, increased iPGE to 2:3 μg/day and PRA from 47 to 73 ng/ml/hour (normal 1 to 3 ng/ml/hour). In the second patient (Case 2), iPGE was 1.4 μg/day. Therapy with ibuprofen, 1,600 mg/day, and indomethacin, 200 mg/day, again resulted in the return of iPGE, PRA, plasma aldosterone and angiotensin pressor sensitivity to normal, but serum potassium increased only transiently from 2.1 to 3.1 meq/liter. The oral administration of potassium chloride, 240 meq/day for four days, increased potassium to 3.0 meq/liter and increased iPGE to 8.0 μg/day. The administration of potassium triplex, 240 meq/day for four more days, further increased potassium to 3.4 meq/liter and iPGE to 9.3 μg/day, and PRA increased from 7.1 to 13.8 ng/ml/hour. This patient (Case 2) was hypomagnesemic (1.0 meq/liter, normal 1.5 to 2.4 meq/liter), and the intravenous administration of magnesium transiently increased iPGE by 15-fold. Following water restriction iPGE returned to normal (0.35 μg/day), and water loading increased iPGE to 3.0 μg/day, but neither maneuver altered PRA, aldosterone or serum electrolytes. The findings that potassium administration failed to reduce iPGE excretion and that water restriction renormalized iPGE excretion suggest that hypokalemia is not the primary stimulus to prostaglandin excretion. © 1979.