The effect of cytostatic drugs on collagen metabolism in guinea pigs.

Azathiprine (0.25 mg/100 g body wt.) and cyclophosphamide (0.2 mg/100 g body wt.) were administered to guinea pigs, orally every day during 4 weeks. Azathioprine caused a decrease in total collagen content in skin, liver and bone and decreased hydroxyproline and hydroxylysine concentration in blood serum, and urinary excretion of collagen catabolites. No effect of cyclophosphamide on total collagen in skin and liver was observed. An increase in collagen content in bone in cyclophosphamide-treated guinea pigs was found. A decrease of hydroxyproline and hydroxylysine in blood serum and urine was observed after cyclophosphamide treatment. The results support the view that cytostatic drugs inhibit collagen metabolism, and azathioprine significantly affects collagen biosynthesis, and cyclophosphamide influences inhibition of catabolic processes of collagen.