[Quantitative determination of the epidermal G2-chalonelike factor in rat tissues by means of radial immunodiffusion].

A high-molecular glycoprotein (epidermal G2 chalone) shown to be homogeneous by electrophoresis and immunochemistry was isolated from rat skin. It exerts a strong tissue-rather than species-specific antimitotic effect on the keratinizing epithelium. The paper is concerned with its quantitative immunodiffusion determination in some tissues by means of monospecific antiserum. A clear-cut correlation between the mitotic index and the epidermal G2 chalone level in the mucosa is shown with special reference to vaginal epithelium of rats during the estrual cycle.