TGF-alpha and olfactory marker protein enhance mitosis in rat olfactory epithelium in vivo

Previous studies demonstrated that both transforming growth factor-alpha (TGF-alpha) and olfactory marker protein (OMP) are potent enhancers of mitosis in fetal rat olfactory epithelium grown in organotypic culture. Here we show that when either of these two peptides is administered to adult rats they elicit a significant increase in uptake of tritiated thymidine ([3H]TdR) by olfactory epithelium. In addition OMP promotes an increase in uptake of [3H]TdR in liver, but TGF-alpha has no effect. The data argue that both peptides regulate the rate of cell division in rat olfactory epithelium in vivo and in vitro, and suggest there may be redundancy in the regulatory apparatus modulating cell division in this tissue.