Cellular Binding Proteins for Vitamin A in Colorectal Adenocarcinoma of Rat

摘要: Rat colorectal mucosa was examined during the course of carcinogenesis, induced by chronic administration 1,2-dimethylhydrazine (DMH), for presence and amount cellular retinol-binding protein (CRBP) retinoic acid-binding protein. These two binding proteins are implicated in action vitamin A normal neoplastic tissue. Induced adenocarcinomas were found to contain low levels (10 pmol/g), similar adjacent same animal also from rats or chronically treated with DMH. However, had high CRBP (300 500 these dramatically higher than (40 100 (20 DMH (22 25 pmol/g). Consequently, increase occurred only tumor appearance not general hyperplasia crypts caused administration. The associated endogenous retinol (77 100% saturation) to, if identical with, tissue, as judged fluorescence spectra, sedimentation behavior, elution position on Sephadex G-75.