Electrophoresis of collagen proteins in MeT-5A cell culture supernatant. Supernatant of cultured fibroblasts was used as standard (STD) for the bands of types I and III collagen. Recombinant HGF (10 and 50 ng/ml), serum, and peritoneal fluid of patients with peritonitis (CAPDP serum, CAPDP fluid) increased the production of collagen types I and III, and the phenomenon was abolished by neutralizing anti-HGF antibody (Ab HGF). Note that type I collagen produced by mesothelial cells consists only of α1 chain, i.e., is a homotrimeric (α1)3 form.