Glucocorticoids Change the Ratio of Type III to Type I Procollagen Extracellularly

Abstract Rat skin fibroblasts were treated with dexamethasone and labeled with radioactive proline for 2 hours. Intracellular and extracellular procollagens were immunoprecipitated with monospecific polyclonal antibodies. Both intracellular and extracellular types I and III procollagen were decreased coordinately by glucocorticoid treatment. The ratio of type III to type I procollagen was -the same for control and dexamethasonetreated cell cultures. However, when rat skin fibroblasts were prelabeled with radioactive proline and chased in the presence of unlabeled proline the ratio of type III to type I extracellular procollagens remained constant in the glucocorticoid-treated cells and increased in control fibroblasts.