Renal Handling of Salt and Water in the Early Stage of Obstructive Jaundice in Rabbits

Abstract

Renal handling of salt and water in the early stage of obstructive jaundice was studied in rabbits 10 days after the ligation of the common bile duct (BDL). Sham-operated (SO) animals served as controls. No sodium retention was found in BDL rabbits, despite reduced renal perfusion and elevated plasma aldosterone level. A redistribution of intrarenal blood flow was not found. The filtration fraction did not change. A saline load resulted in decreases in arterial hematocrit and total serum proteins, and increases in urine output, urinary sodium excretion and osmolal clearance. Blood pressure, glomerular filtration rate (GFR), RPF, the filtration fraction and the intrarenal flow distribution were not significantly affected by the saline load. No significant difference was found in the natriuretic response to the saline load between the BDL and SO groups. After 60 h of water deprivation, there was no significant difference in urine-to-plasma osmolality ratios or renal tissue fluid osmolality between the BDL and SO animals. The findings indicate that renal handling of salt and water was well maintained in the early phase of obstructive jaundice in rabbits. The data also suggest the critical role of the redistribution of intrarenal blood flow rather than of GFR or aldosterone in determining sodium retention in obstructive jaundice.