Differential distribution of transforming growth factor beta and receptors in the hyper or hypoproliferative gastric mucosa of developing and adult rats.

Transforming growth factor beta (TGFbeta) isoforms are known for their antiproliferative effect on epithelial cells in vitro, but the role of each isoform in vivo is poorly understood, mainly when non-pathological conditions are considered. We correlated the presence and distribution of isoforms and receptors to physiological changes in gastric cell proliferation in developing and adult rats. We used fasting to induce either the hyper (14-day-old pups) or hypoproliferation (60-day-old rats) of the gastric epithelium. In 14-d-old pups fasting reduced only TGFbeta3 labelling in the gland. Conversely, in 60-d-old rats there was an increase of TGFbeta1 and TGFbeta3 immunolabelled cells. Receptors were detected at both ages. Therefore, the changes induced by fasting in the constitutive TGFbeta expression can be correlated to the differential epithelial proliferation in the stomach of developing and adult rats. These results suggest that one of the functional roles of TGFbeta in vivo is to locally regulate cell proliferation.