Antidiuresis and decreased sodium excretion during cyclo-oxygenase inhibition in the conscious dog

Studies were undertaken to further elucidate the role of endogenous prostaglandins in normal renal function in the awake dog. Meclofenamate (2 mg/kg and 2 mg/kg/h, i.v.) was administered after control measurements. Parallel time control experiments were also performed. Inhibition of renal prostaglandin synthesis was documented by significant reduction in urinary prostaglandin E2 excretion rate. Urine flow and sodium excretion were reduced by meclofenamate infusion. In addition, fractional excretion of sodium was reduced, implying enhanced sodium reabsorption during prostaglandin synthesis inhibition. Renal hemodynamics, glomerular filtration and systemic hemodynamics were unaffected. It is concluded that endogenous prostaglandin release is important in influencing sodium and water excretion in the conscious dog.