Steroid metabolism by cells from human chorion laeve isolated on Percoll gradients.

Collagenase-dispersed cells from human chorion laeve were examined on Percoll gradients. The 3 beta-hydroxysteroid dehydrogenase (a trophoblast marker) and steroid sulfatase activities of the cells were measured and a system was developed to isolate enriched preparations of the trophoblast cells. No cells were found to sediment at Percoll concentrations greater than 50%, and using continuous gradients of Percoll there appeared to be cells with different 3 beta-hydroxysteroid dehydrogenase (3 beta HSD): steroid sulfatase ratios sedimenting in different regions of the gradient. Cells with a high ratio were found in the denser region of the gradient. Continuous gradients provided inadequate separations of distinct populations of cells, thus to obtain a more reproducible system to isolate cells, discontinuous gradients of Percoll were studied. A discontinuous gradient composed of 5, 20, 40, and 60% Percoll was developed and three bands of cells were found sedimenting at the 20, 40 and 60% interfaces, respectively. The number and appearance of cells at the 20 and 60% interfaces varied from tissue to tissue. In contrast, the cells sedimenting at the 40% interface were less variable, a substantial number was found to be present in every tissue studied, they were similar in appearance to the trophoblast cells and had high 3 beta HSD:sulfatase ratios.