The collagen composition of the dystrophic hamster diaphragm.

1. Diaphragms from BIO 14.6 dystrophic hamsters had lower dry weights and higher collagen content than did controls, BIO F1B. 2. The increase in pepsin-solubilized collagen affected mainly types III and V, and there was a concomitant decrease in the beta and high molecular weight (HMW) collagen aggregates. 3. These findings are similar to the observations in myotonia congenita and imply that the dystrophic process increases collagen synthesis. 4. In addition, there is possibly a genetic mutation of amino acids at points of contact of collagen monomers. 5. Alternatively, there may be reduced hydroxylation of lysine residues and hence in the degree of glycosylation of collagen resulting in decreased cross-linking and aggregation.