Effect of induced elevated plasma levels of homocystine and methionine in rats on collagen and elastin structures.

Young growing rats were intraperitoneally injected with mixtures of homocystine and methionine for several weeks. The growth of the animals was inhibited. After 3 weeks 25% of the rats died and isolation of tail tendon collagen and aorta elastin showed that these proteins were deficient in chemical cross-links. Seventy-five % of the rats survived further injections for another 3 weeks and isolated collagen and elastin were found to be normal in cross-linking. The variability in susceptibility of these rats to homocystine-methionine treatment is discussed in relationship to human homocystinuria. It is speculated that the variability is due to variability in in vivo homocysteine levels.