The proliferative response of mouse jejunal crypt cells to radiation-induced cell depletion is not mediated exclusively by transforming growth factoralpha

Several lines of correlative evidence link transforming growth factor alpha (Tgfa, also known as TGF-alpha) to proliferative activity in jejunal crypt cells. It is therefore tempting to hypothesize that, as a ligand of the ep idermal growth factor, it mediates the compensatory proliferative burst in the crypts after radiation-induced cell killing. We have tested this hypoth esis by comparing the repopulation response of wild-type and Tgfa-null mice , using the microcolony assay. Mice were exposed whole-body to Cs-137 gamma rays at a dose of approximately 1.6 Gy/min, Single doses and equal doses s eparated by 4 and 54 h were given. The rightward shift of the dose-response curves for 54 h was identical for wild-type and Tgfa-null mice, and there was no indication of a difference in radiosensitivity, This result indicate s that Tgfa is not an essential component of the proliferative response of tissue to radiation-induced cell killing. (C) 2001 by Radiation Research So ciety.