Evaluation of hepatic functional reserve in rats with obstructive jaundice by asyaloglycoprotein receptor

Until now, there has been no adequate means of evaluating the liver functional reserve in cases with obstructive jaundice. 99mTC-GSA (99mTechnetium-DTPA-Galactosyl-human serum albumin) is a new liver-imaging agent which binds specifically to the asyaloglycoprotein-receptor on the membrane of hepatocytes. So, the liver imaging by GSA excludes the influence of the reticuloendothelial system. Therefore, the uptake of 99mTC-GSA is considered to be a useful method for the estimation of liver functional reserve in cases with obstructive jaundice.

In this study, we examined the uptake rate and specific binding capacities of 99mTC-GSA to receptors on the membrane of hepatocytes following 1, and 2 weeks of bile-duct ligation and 1 week after reduction of jaundice using the rat model.

The hepatic uptake rate decreased as the period of jaundice was prolonged and returned to nearly normal by the reduction of jaundice. The value of specific binding capacities at 2 weeks after bile-duct ligation decreased significantly compared to the value of the control and the reduced group (P < 0.05). The cause of decrease in specific binding capacities was indicated as the decrease of affinity constant especially in the high affinity part. These results coincide with the change of binding capacities of insulin and glucagon receptors with obstructive jaundice, which accurately reflect the severity of hepatocyte injury.

Taking together these results, 99mTC-GSA liver scintigraphy is thought to be a useful method to evaluate the liver functional reserve in cases with jaundice.