[Biochemical study of cultured hepatocytes obtained from normal adult rats].

A method has been developed for the preparation of hepatocytes that contained 98.6% of that cell type with a yield of 50%. No change was detected in the DNA content per nucleus but losses were noted in RNA and proteins in freshly isolated hepatocytes.

Ribonucleases and neoplasia.

Biochemical data provide good evidence of a lack of acid and alkaline RNase activities in ascites tumour cells. Analyses of whole solid tumours appear of doubtful value, but fractionation studies reveal RNase deficiencies in mitochondrial fractions whereas inconsistent results are reported for microsomal fractions. Nuclei, nucleoli, and ribosomes isolated from tumours show relatively weak activities.

Biochemical estimation of the basic dye-binding capacity of RNA from rat hepatoma.

Areas of hyperplastic livers that acquire hyperbasophilic properties at advanced stages of carcinogenesis apparently represent the sites of neoplastic trasnformation, and hyperstaining of cytoplasmic RNA with basic dyes also characterizes the cancer cells. Estimations of the RNA content of cell fractions from normal rat liver and solid Novikoff hepatoma provided no evidence that the intense staining of cancer cells could be explained on the basis of an increase in cytoplasmic RNA content. The possibility that cytoplasmic fractions of Novikoff hepatoma show greater affinity for basic dyes than corresponding normal fractions has been examined by means of a test-tube toluidine blue-binding assay.

Isolation of arginine acceptor-proteins from normal rat liver and Novikoff hepatoma supernatant.

In the present report a procedure for the isolation of more specific arginine receptors from the soluble fraction of rat liver and Novikoff hepatoma is described. In normal rat liver the specific activity of these receptors from the soluble fraction of rat liver and Novikoff hepatoma is described. In normal rat liver the specific activity of these receptors is fifteen times greater than that of the other proteins whereas in the Novikoff it is only three to four times higher.