Abstract
A 51 year old male with features typical of Bartter's syndrome is described. Several theories have been proposed to explain the pathogenesis of this disorder. Lataly, loss of sodium at the proximal tubule or ascending limb of Henle's loop was disclosed These tubular defect led to extracellular fluid volume depletion and consequent stimulation of the renin-angiotensin-aldosterone (RAA) axis. On the other hand, it is well known that prostaglandins have a potent natriuretic action. We therefore investigated the response of this patient to β-adrenergic blockade with propranolol, and indomethacin, potent inhibitor of prostaglandin biosynthesis. Prostaglandin E1(PGE1), plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured by radioi mmunoassay. Measured PGE1 ranged from 10.1 to 25.4 ng/ml and clearly exceeded the normal range for adults of 1. 56 ±0.98ng/ml. Treatment with indomethacin, which decreased plasma PGE1 level by 73.5 per cent, did not affect blood pressure, significantly. And PRA decreased from 10.1 to 1.8 ng/ml/hr and PAC, from 44.0 to 10.2ng/dl. Serum potassium level and angiotensin sensitivity recovered to normal level with the treatment of indomethacin. Angiotensin II analogue which acted antagonistically before treatment, acted agonistically after treatment as in normal adults. Propranolol suppressed the elevation of PRA and PGE1, but they remained still over the normal range, and serum potassium level stayed within normal range. These results suggest that the renal salt wasting caused by excessive prostaglandins in this disorder, stimulates the RAA axis and results in secondary hyperaldosteronism. Suppresed prostaglandin synthesis by indomethacin may have a important role on dramatic improvement of clinical features of Eartter's syndrome.
