Effects of glucocorticosteroids on primary human skin fibroblasts. I. Inhibition of the proliferation of cultured primary human skin and mouse L929 fibroblasts.

Various glucocorticosteroids were added to logarithmically growing cultures of primary human skin fibroblasts and of mouse L929 fibroblasts. These steroids inhibited proliferation of the human fibroblasts at concentrations which fall in a range expected to occur during the topical treatment of skin disorders. In terms of the concentrations required for the inhibition hydrocortisone was least and clobetasol-17-propionate most effective. All other steroids studied (hydrocortisone-17-butyrate, triamcinolone acetonide, betamethasone-17-valerate and hydrocortisone-21-acetate) showed medium effectiveness. Fluorination as such may not enhance the inhibitory effect. The inhibition was independent of the source (baby foreskin or adult arm skin) and passage number (7th to 13th or 15th and 16th passage, respectively) of the cells. The possible relationship between the inhibition of cell proliferation by such steroids and their therapeutic effect in psoriasis and their atrophic side effects is discussed. Mouse L929 fibroblasts were affected at 10(3)--10(4)-fold lower steroid concentrations and the range of the effective concentrations was 10(4)--10(5) times as wide as that for the primary human skin fibroblasts. It was concluded that these mouse fibroblasts are a poor model system for the study of in vivo effects of glucocorticosteroids in man.