[Effect of isoproterenol on collagen synthesis in cultured skin fibroblasts in patients with systemic scleroderma]

Production of collagen and intracellular content of 3,5'-cAMP were studied after treatment with isoproterenol of fibroblast cultures of II-XI passages obtained from healthy donors and from patients with systemic scleroderma. Incubation of control fibroblasts with isoproterenol within 6 hrs caused an increase in the cell cAMP concentration by 260-385% and inhibited the collagen synthesis by 27-58%. Distinct correlation (r = -0.951) was found in fibroblasts of the patients with sclerodermia between the capacity of the cells to accumulate cAMP in presence of isoproterenol and their ability to produce collagen. The inhibitory effect of isoproterenol on collagen synthesis was not found in the cells with initially increased collagen-producing activity, but the effect was maintained in the strains with the decreased rate of collagen synthesis. The data obtained suggest that impairments in beta-adrenergic functions and the decrease in cAMP concentration in fibroblasts may be responsible for the elevated rate of collagen synthesis in the patients with systemic sclerodermia.