Neural retinal and pigment epithelial cells in culture: patterns of differentiation and effects of prostaglandins and cyclic-AMP on pigmentation

Cluck neural retinal cells are relatively undifferentiated in appearance for several weeks in culture. Cells with long, thin processes are subsequently observed as well as foci of small, pigmented cells and large semi-transparent masses of cells or other material. Retinal cells thus appear to be able to differentiate into several divergent cell types in vitro. Chick pigment epithelial (PE) cells rapidly differentiate in culture, forming microvilli, pigment granules and other specialized subcellular organelles. 5-Bromodeoxyuridine greatly inhibits cellular differentiation of cultured PE cells as assessed by decreased visible pigmentation and by colonial disorganization. In contrast, several prostaglandins and dibutyryl cyclic-AMP plus isobutylmethylxanthine increase pigmentation and induce a more mature type of cell morphology and colonial development. By electron microscopy, increased numbers of pigment granules are apparent as well as an increase in the length of microvilli. Prostaglandins also increase glutathione levels in the cells. Prostaglandins and cyclic-AMP thus promote the general state of differentiation of PE cells in culture.