RETINOIC ACID-BINDING PROTEIN IN NORMAL TISSUES AND EXPERIMENTAL-TUMORS

Abstract

The tissue distribution of retinoic acid-binding protein (RABP) was determined for tissues of chick embryos and young and adult rats and mice and was compared with other published data. Although no species variability was detected with tissue distribution of RABP, relatively more of the protein is detected in the tissues of young animals than in those of adults. This protein is below the limits of detection in adult rat or mouse brains, whereas it was present in abundance in embryonic and young brains. RABP is present in epithelial cells but not in the connective tissue of skin. Besides brain, skin, testis and eye, RABP is also detected in small quantities in the bladder, prostate, uterus, trachea and mammary glands of rats and mice. Although RABP could not be detected in normal lungs, this protein is present in Lewis lung tumors and in lungs with metastatic Lewis lung foci. Of 4 chemically induced transplantable colon tumors of mice, 2 highly metastatic ones contained RABP, whereas the 2 nonmetastatic lines as well as normal colon did not.