TGF-ALPHA IS A POTENT MITOGEN FOR PRIMARY CULTURES OF GUINEA-PIG GASTRIC MUCOUS EPITHELIAL-CELLS

TGF-alpha is a potent mitogen for primary cultures of guinea pig gastric mucous epithelial cells. Am. J. Physiol. 265 (Gastrointest. Liver Physiol. 28): G361-G369, 1993.-Transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) are thought to be important in gastric epithelial proliferation and repair. It was therefore of interest to determine if TGF-alpha and EGF promoted the growth of an in vitro primary culture system of guinea pig gastric mucous epithelial cells (MEC). MEC were isolated from guinea pig stomachs and cultured in 24-well Primaria plates with DMEM with or without 10% fetal calf serum (FCS). Growth of MEC was determined by changes in [H-3]thymidine uptake, cell counts, protein, and DNA. The sources of peptides were human recombinant TGF-alpha (recTGF-alpha) and human recombinant EGF (recEGF). Both recTGF-alpha and recEGF were used at equipotent doses as determined by competing activity in a I-125-labeled TGF-alpha radioreceptor binding assay using A-431 cells. Basal growth (no peptides) of MEC in 10% FCS was dependent on the initial plating density. Under serum-free conditions, [H-3]thymidine uptake increased up to 17-fold at 24 h with recTGF-alpha (0.1-10.0 nM) compared with only a 4-fold increase using rec-EGF (0.1-10.0 nM) at this same time period. Under serum-free conditions, recTGF-alpha (0.01-10.0 nM) increased cell counts up to 4.9-fold over control cultures, whereas similar does of recEGF produced a 2.5-fold increase in cell counts. Administration of recEGF (1 ng/ml) resulted in a 1.9-fold increase in the 4.8-kb TGF-alpha mRNA transcript, and TGF-alpha protein immunoreactivity was found in both 24-h conditioned media and cell lysates. We conclude that TGF-alpha is a more potent mitogen for guinea pig gastric mucous cells, and the data suggest that TGF-alpha may act as an autocrine factor for these cells.