| Abstract: | ![]()
The steroidogenic capacity of cells cultured from the definitive zone and fetal zone of the human fetal adrenal cortex was compared, using a serum-free medium without lipoproteins. Comparison of [3H]pregnenolone and [3H]progesterone metabolism in cultures from each zone incubated without ACTH indicated that only 3 beta-hydroxysteroid dehydrogenase, delta 4,5-isomerase (3 beta-HSD) activity was deficient in fetal zone cultures. Basal 3 beta-HSD activity was 3- to 5-fold lower in fetal zone cultures than in definitive zone cultures assayed after 3 or 10 days in culture. Although basal hydroxysteroid sulfotransferase activity was 2- to 4-fold greater in 3-day-old fetal zone cultures than in definitive zone cultures, this difference was not found in 10-day-old cultures due to a 3-fold decrease in fetal zone basal hydroxysteroid sulfotransferase activity. However, older cultures of fetal zone cells did maintain the characteristic high delta 5-steroid sulfate and low delta 4,3-ketosteroid basal production from [3H] pregnenolone as compared to definitive zone cultures. ACTH treatment for 48 h in serum-free medium increased the steroidogenic capacity of cell cultures from both zones and stimulated delta 4,3-ketosteroid production from [3H]pregnenolone and 3 beta-HSD activity in fetal zone cultures to levels characteristic of the definitive zone. These studies show that in the absence of ACTH the difference in steroidogenic capacity between the fetal zone and the definitive zone (due to the lower 3 beta-HSD activity in fetal zone cells) was maintained in cell cultures for a period up to 10 days. |
