The proliferative response of mouse jejunal crypt cells to radiation-induced cell depletion is not mediated exclusively by transforming growth factor alpha.
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 epidermal growth factor, it mediates the compensatory proliferative burst in the crypts after radiation-induced cell killing. We have tested this hypothesis by comparing the repopulation response of wild-type and Tgfa-null mice, using the microcolony assay. Mice were exposed whole-body to (137)Cs gamma rays at a dose of approximately 1.6 Gy/min. Single doses and equal doses separated 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 indicates that Tgfa is not an essential component of the proliferative response of tissue to radiation-induced cell killing.
Evans
S C
SC
Department of Molecular Genetics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
Mack
D C
DC
Mason
K A
KA
Thames
H D
HD
D000818:Animals; D002455:Cell Division / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D007583:Jejunum / Q000166:cytology / Q000528:radiation effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016211:Transforming Growth Factor alpha / Q000235:genetics / Q000502:physiology*
D016211:Transforming Growth Factor alpha