Changes in the ribonucleic acid metabolism of aging mouse tissues with particular reference to the prostate gland

1. Mouse mast-cell tumours P815 Y and HC were shown to contain glycoprotein material composed of glucosamine, galactosamine, sialic acid, galactose and mannose. 2. The major amino acids released after acid hydrolysis of Pronase-treated digests of the glycoprotein are aspartic acid, glutamic acid, serine, threonine, proline, glycine and alanine. The Pronase-digested material is not degraded in alkaline solution. 3. On incubation of mast cells with (35)S]sulphate, heparin is the major radioactive product. However, 1-(14)C]glucosamine and d-(14)C]glucose are incorporated largely into the glycoprotein. 4. The fate of (35)S]sulphate-labelled and 1-(14)C]glucosamine-labelled material was studied. In each case high-molecular-weight radioactive material is released from the cells into the culture medium. The t((1/2)) of (35)S]sulphate-labelled material in cells is 70hr. and that of 1-(14)C]-glucosamine-labelled material in cells is 40hr. 5. About 60% of the (35)S]sulphate-labelled material is present in the mitochondrial and granular fraction. 1-(14)C]-Glucosamine-labelled material is present in both microsomal and mitochondrial and granular fractions, (14)C]sialic acid being concentrated in the microsomal fraction.