EFFECTS OF CALCITRIOL ON PROLIFERATION AND DIFFERENTIATION OF HUMAN FETAL JEJUNUM

Several lines of evidence suggest a role for calcitriol in the regulat ory mechanisms of intestinal development. Using organ culture as a mod el, we have verified whether this hormone influenced the cellular prol iferation and differentiation processes of the developing human jejunu m. We show that calcitriol supports a proliferative process in the fet al human jejunum at II weeks of gestation and a differentiating activi ty in samples obtained between 16 and 20 weeks. The present data there fore suggest that calcitriol has a biphasic effect on the development of the human intestinal epithelium and warrants caution in extrapolati ng to human, data observed in developing rodents and human carcinoma c ell lines.