Isolation of a lipocyte-rich fraction from rat liver nonparenchymal cells

A modified pronase digestion procedure is described for isolating nonparenchymal liver cells from vitamin A treated rats, which yielded a 15-23% population of lipocytes in the total cell suspension. The criteria for defining a lipocyte was the appearance of vitamin A containing cells as determined by fluorescent microscopy. Measurement of alcohol dehydrogenase and retinol dehydrogenase activities indicated that these enzyme activities were not present in the isolated nonparenchymal cells. A lipocyte-rich fraction of nonparenchymal cells was obtained by centrifugation of purified nonparenchymal cells in a linear Metrizamide gradient. Vitamin A fluorescence and chemical assay of vitamin A in the cell fractions indicated a four-fold enrichment of lipocytes in the cell fraction with d = 1.043 g/ml. Fractions high in vitamin A also had numerous cells with fat droplets as shown by transmission electron microscopy.