Intercellular hormones

Abstract

It has been demonstrated that factors of the vitamin B complex account in part for the proliferationpromoting activity ('wound hormone' effect) of pro- ducts from yeast cells slowly damaged by sublethal ultra-violet radiation, and that the living, damaged cells appear to elaborate considerable quantities of certain of these factors (notably biotin and panto- thenic acid) during the course of injury (Webb & Loofbourow, 1947).