Changes in elastin composition in aorta of spontaneously hypertensive rats (SHR).

Tropoelastin and elastin preparations obtained from aortae of spontaneously hypertensive rats (SHR) show an increased proportion of polar amino acids (aspartic acid, glutamic acid, arginine and tyrosine). The content of these amino acids is 1.43-3.04 times higher in SHR rats than in similar elastin or tropoelastin preparations obtained from normotensive animals. On the other hand elastin and tropoelastin preparations obtained from SHR rats show a lower frequency of the Val-Pro sequence; this was found to be 35.93 per 1000 amino acid residues in SHR rats as compared to 51.04 per 1000 amino acids in the preparations obtained from control animals. Since similar differences were found not only in elastin preparations but also in tropoelastin, contamination of these preparations with an acidic protein seems unlikely. In general the results obtained are similar to those seen in animals kept on a long term high fat diet. It appears feasible to suggest that these differences are caused by a changed proportion of two different elastin type.