Metabolism in hypothermically perfused human kidney carcinoma: incorporation rate of leucine into proteins.

Protein synthesis in tumour-involved human kidneys was studied before, during and after hypothermic perfusion. Before and after perfusion the incorporation rate of leucine into tumour and kidney cortex proteins was determined by incubation of tissue slices at 37 degrees C. During perfusion the incorporation of leucine from the perfusate into tumour and kidney cortex proteins was determined. Before hypothermic perfusion the incorporation rate of leucine into proteins at 37 degrees C was almost the same in kidney cortex and tumour. Leucine was incorporated linearly with time into kidney cortex and tumour proteins during hypothermic perfusion but the incorporation rate was 3-4 times higher into kidney cortex proteins than into tumour proteins. After 6 days of hypothermic perfusion the leucine incorporation rate into proteins at 37 degrees C was depressed by 50% in kidney cortex and by 90% in tumour tissue. The specific activity of leucine in the perfusate decreased during the perfusion period indicating a release of leucine from degradation of proteins. It is concluded that the effect of hypothermic perfusion on protein synthesis was more pronounced in the tumour than in the normal renal parenchyma.