Free Water Excretion and Washout of Renal Medullary Urea by Prostaglandin E1

Prostaglandin E1 (PGE1) was infused directly into the left renal artery of anesthetized dogs. In the infused kidney, there occurred increases in sodium and water excretion with increased RPF and decreased EPAH. Distinctly hypotonic urine was excreted even without solute diuresis in the infused kidney, when control urine and urine in contralateral kidney was hypertonic. Rapid washout of renal medullary urea was also observed in the infused kidney and transitory increase in urea excretion made urea to creatinine clearance ratio more than unity. The effects may have resulted from either hemodynamic effect alone or from both hemodynamic and anti-ADH effect of PGE1. The present study may seem to support the presence of a direct anti-ADH action of PGE1 in vivo.