Flow and composition of renal hilar lymph during volume expansion and saline diuresis

Volume expansion of 5-10% body weight in dogs was achieved by infusion of 0.9%, 1.2% or 0.4% saline. The average diuretic response for each group was 9.9 +/- 2.1, 5.5 +/- 0.6 and 3.3 +/- 0.9 (mean +/- S.E.) ml/hr/kg respectively. Flow from single hilar lymphatics increased by an average of 150%, there being no significant difference between the groups. A significant (p less than 0.02) positive correlation was found between the increase in hilar lymph flow and thoracic duct lymph flow. No correlation was found between hilar lymph flow and the extent of the diuresis. Control hilar lymph contained higher concentrations of Na+ (L/P = 1.05) and C1- (L/P = 1.12) (p less than 0.001) and lower concentrations of glucose (L/P = 0.86) (P LESS than 0.001) than did simultaneous plasma. The electrolyte lymph-to-plasma differences were maintained despite increases or decreases in plasma concentrations. The results indicate that changes in hilar lymph flow are related to volume expansion rather than to the diuresis, and that the processes responsible for lymph-to-plasma compositional differences are relatively unaffected by changes in plasma levels.