Effect of corticosteroids on the morphology and proliferation of two salmonid cell lines.

In medium with cortisol at 5 ng/ml and greater, cells of the rainbow trout cell line, RTG-2, lost their fibroblast-like morphology and became flattened and epithelial-like. This also occurred with dexamethasone triamcinolone acetonide, and fluocinolone acetonide but not with cortisone, progesterone, estradiol, or testosterone. Maintenance in medium with cortisol but not with cortisone caused these cells to adhere more tightly to the growth surface. The addition of cortisol at 100 ng/ml to RTG-2 cultures reduced the saturation densities that were achieved after monolayers had formed but had no effect on the times to reach confluency. Cortisone had no influence on cell population growth. Neither cortisol nor cortisone altered the morphology, adhesion, or proliferation of the Chinook salmon embryo cells, CHSE-214.