Protein Metabolism among Lobes of the Rat Liver in Relation to Site of Radioisotope Injection 1

Abstract

Summary

Protein metabolism among rat liver lobes was studied by leucine-³H injections coupled with liquid scintillation spectrometry of TCA-tungstate soluble and insoluble fractions. All liver lobes appeared to metabolize protein in identical fashion when the label was injected in the external jugular vein. On a per milligram of wet weight basis, the lobes exhibited similar values of radioactivity at the various experimental times. When this data was converted to total radioactivity per lobe a positive correlation was revealed between total lobe radioactivity and lobe weight. However, when the radioisotope was injected directly into the spleen, it was the right side of the liver which contained most radioactivity 15 min later. Whereas leucine-³H injection into the lumen of the jejunum resulted in lobes of the left side having most radioactivity 15 min later. This was interpreted as a crossing-over of streamlined blood flow in the rat portal vein under these experimental conditions.

The authors gratefully acknowledge the suggestions and advice of Drs. G. W. Bernard, J. H. Campbell, J. N. Hayward, D. C. Shepard, and J. D. Thrasher.