1. Rats treated orally with vinyl chloride (30 mg/kg) daily for 2 years developed a syndrome which included thickening of the skin.
2. Analysis of the skin showed a 26% increase in collagen deposition per unit weight, and a corresponding 30% increase in the levels of glycosylated lysine and hydroxylysine. There was a significant increase in the amounts of the labile borohydride reducible cross-links, such as the intermolecular hydroxylysinonorleucine (+ 31%) and histidinomerodesmosine (+ 42%) as well as the intramolecular allysine aldol cross-links (+ 17%).
3. These results provide evidence that fibrosis of the skin is one of the pathological consequences of exposure to vinyl chloride.