Effect of cystamine on protein, phospholipid and RNA synthesis or degradation.

Cystamine administration to rats partially inhibited (14C)-leucine incorporation to microsomal proteins, and (14C) orotic acid incorporation to RNA but markedly stimulated (32P) incorporation to liver microsomal phospholipids. Cystamine administration did not modify the decay of radioactivity of liver microsomal lipids prelabeled with (32P) or of microsomal protein prelabeled with [(14C)-guanidino]arginine. Notwithstanding cystamine increased the RNA content in total liver. Results suggest that cystamine inhibits protein synthesis, stimulates phospholipid synthesis and inhibits RNA synthesis and degradation.