THE QUANTITATIVE HISTOCHEMISTRY OF THE NORMAL HUMAN LIVER LOBULE.

Abstract

Abstract With the use of microdissection and microchemical techniques, measurements were made of protein, desoxyribosenucleic acid, and seven enzymes in periportal and centrolobular areas of the normal human liver lobule. The whole portal tracts and their components were also studied. The enzymes measured participate in one or more systems in the metabolism of carbohydrates: glycolysis, glucogenesis, the pentose pathway, the tricarboxylic acid cycle, and gluconeogenesis. Alkaline phosphatase was also measured. Activities being expressed on either a protein or a desoxyribosenucleic acid basis, phosphoglucoisomerase and lactic dehydrogenase were demonstrated to be more active in periportal areas of the normal, human liver lobule, but isocitric dehydrogenase, ,glucose-6-phosphate dehydrogenase, and alkaline phosphatase were more active in centrolobular areas. Malic dehydrogenase and glutamic-pyruvic transaminase had comparable periportal and centrolobular activities. On both a protein and a desoxyribosenucleic acid basis, the whole portal tract revealed a greater activity for glucose-6-phosphate dehydrogenase than did parenchymal cells, but relatively lower activities for the other six enzymes. A study of the components of the portal tract on a desoxyribosenucleic acid basis revealed that arterioles and venules contribute importantly to the activity of each enzyme in the portal tract as a whole. Halt, ever, in the bile ducts, only alkaline phosphatase, malic dehydrogenase, glucose-6-phosphate dehydrogenase, and phosphoglucoisomerase contributed importantly to the activity in complete portal tracts. These -results in the human liner lobule are compared to our previously reported intralobular distributions of enzyme activities in the normal rat liver. In both species, enzymes participating in anaerobic glycolysis have higher periportal activities, while those participating in the aerobic metabolism of carbohydrates have higher centrolobular activities.