Growth-factor-like substance in amniotic fluid in the rat: effect on the development of fetal colonic goblet cells

Extra- and intrauterine fetuses were studied to explore the effect of amniotic fluid on the development of colonic goblet cells. Significant differences in the density of goblet cells in developing colon were observed during fetal days 19-22 between these two groups, suggesting that amniotic fluid affects the development of the colonic goblet cells, especially during the period between days 19 and 21 when rat fetuses began to swallow amniotic fluid, as demonstrated by injecting India ink into the amniotic cavity. By immunological dot blot analysis, the amniotic fluid and gastric juice from intrauterine fetuses were positive for epidermal growth factor (EGF), whereas maternal abdominal serous fluid and gastric juice from extrauterine fetus were negative for EGF. The present results indicate that the amniotic fluid during late gestation greatly affects the development of the colonic goblet cells in rat fetuses and that the trophic factors for the cells seems to be EGF or an EGF-like substance in the amniotic fluid.