Prostaglandins PGE2 and PGF2 alpha in human fetal lung: immunohistochemistry and release from organ culture.

Immunohistochemical studies in human fetal lung have shown that epithelial and endothelial cells are both strongly and equally reactive for PGE2. In contrast, epithelial PGF2 alpha reactivity varied between fetuses, in some as intense as endothelial staining and in others very much less. As lung organ cultures differentiated, the intensity of PGE2 staining declined in airways and blood vessels, although it was still weakly positive at 10 days. In contrast, epithelial cells rapidly became negative for PGF2 alpha, whereas PGF2 alpha positivity was retained in blood vessels, albeit less obviously. PGF2 alpha and PGE2 were released into the media of organ cultures in decreasing amounts as cultures progressed. Amounts of released PGF2 alpha were greater by 2- to 10-fold than PGE2. Our findings suggest that the endogenous production of prostaglandins by human fetal lung in organ culture has a key role in the self-differentiation process that occurs in the absence of sera or added growth factors or hormones.