Regulation of collagen secretion by ascorbic acid in 3T3 and chick embryo fibroblasts

Abstract

Ascorbate is required for optimal collagen secretion in Balb 3T3 fibroblasts and chick embryo bone fibroblasts. When 3T3 cultures are supplemented with ascorbate, there is a lag phase of approximately 45 min. before collagen secretion begins while in the absence of the vitamin, collagen accumulates in the cells until secretion begins at a slower rate after 1.5–2 hr. Collagen synthesized and secreted in the absence of ascorbate is extensively underhydroxylated (10–20% of optimum). In chick embryo cells, collagen secretion is also stimulated by ascorbate but, in addition, total collagen synthesis is decreased in the absence of the vitamin. It is suggested that the reduced secretion of collagen, which is probably caused by a deficiency of hydroxylation of proline and lysine in the absence of ascorbate, may eventually produce the defect in collagen synthesis which is observed in scorbutic animals.