Urinary excretion of prostaglandin E2 and prostaglandin F2alpha in potassium-deficient rats.

Potassium-deficiency was induced in rats by dietary deprivation of potassium. The animals became polyuric and urine osmolality decreased more then three-fold compared to controls. Urinary excretion of prostaglandin E2 (PGE2) and prostaglandin F2alpha (PGF2alpha) did not increase during 2 weeks of potassium depletion. Partial inhibition of renal prostaglandin synthesis by meclofenamate did not increase the urine osmolality after water deprivation. These results make unlikely the hypothesis that the polyuria of potassium-deficiency, is the result of enhanced renal synthesis of prostaglandins with subsequent antagonism of the hydro-osmotic effect of vasopressin. Male animals consistently excreted less PGE2 than female animals.