Collagen synthesis regulation by the aminopropeptide of procollagen i in normal and scleroderma fibroblasts

The effect of the aminopropeptide of type I procollagen, Col 1(I), on collagen synthesis by normal and scleroderma fibroblasts was investigated. Collagen synthesis was inhibited by about 42% when normal fibroblasts were labeled with 3H-proline in the presence of 4 microM Col 1(I). In contrast, collagen synthesis by scleroderma fibroblasts was inhibited to a lesser degree, about 19%. Furthermore, scleroderma fibroblasts with elevated rates of collagen synthesis (2.5-5 times normal) were inhibited by only about 10%. The data suggest that the increased accumulation of collagen in the skin of scleroderma patients may be related to a defect in the regulation of collagen synthesis by the aminopropeptide.