Effects of Transforming Growth Factor α and β on Rabbit Gastric Epithelial Cell Proliferation

The effects of epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha), insulin-like growth factor-I (IGF-I), and transforming growth factor beta (TGF beta) on tritiated thymidine incorporation into DNA by rabbit gastric epithelial cells were investigated. EGF, TGF alpha, and IGF-I at concentrations of 10(-10) and 10(-9) M all produced a serum-like stimulatory effect, whereas TGF beta at both concentrations was inhibitory. Coadministration of TGF alpha had no additional effect on EGF-stimulated tritiated thymidine incorporation into DNA. On the other hand, coadministration of TGF beta abolished EGF-stimulated tritiated thymidine incorporation into DNA, suggesting possible interactions between the two growth factors.