Weiss and Ferris1 of Rockefeller University proposed in 1957 that mature cells synthesize and release a chemical messenger that inhibits further replication of immature cells. This chemical, found mainly in epithelial tissues and supposedly responsible for the regulation of epithelial regeneration, has been named chalone. Epidermal chalone was thoroughly investigated and proved to be a new entity, not a known hormone in the epithelial tissue.
Quite a few types of chalones have been isolated thus far. Most of them appear to be glycoproteins and have a molecular weight of about 30,000 to 50,000 daltons; granulocytic chalones, however, have a mass of less than 3,000 daltons. Much of the original work with chalones, especially on their role in suppressing or stimulating proliferation of malignant tissue, was done by Rytömaa and Kiviniemi2 and by Bullough and Laurence3 in the 1960s.
Recently, chalones have created renewed interest in the medical