Collagen prolyl hydroxylase levels in experimental paraquat poisoning.

Collagen prolyl hydroxylase activity was measured in lung, liver, kidney and serum in rats killed on 7 successive days following a single toxic dose of paraquat. The enzyme activity in liver initially fell, then returned to normal, and no change was found in kidney. In contrast a 5-fold rise was observed in lung enzyme level, reaching of maximum on the 5th day. A parallel rise in serum activity was also found. The onset of these enzyme elevations corresponds to the early histological appearance of cellular proliferation in lung alveoli.