A new restriction fragment length polymorphism in the first intron of the spontaneously hypertensive rat renin gene.

1. Amplification of the entire first intron of the renin gene of spontaneously hypertensive rat (SHR), Wistar-Kyoto (WKY) and Sprague-Dawley rats (SD) followed by Bgl II digestion uncovered a new deletion (approximately 50 bp) which exists upstream of the SHR renin gene first intron tandem repeat element. 2. The SHR tandem repeat element was 600 bp shorter than that in the WKY while the WKY tandem repeat element was 280 bp shorter than that in the SD. 3. Since elements regulating gene expression are known to exist in the first intron of other genes, this new restriction fragment length polymorphism (RFLP) might play a role in the reported overexpression of the SHR renin gene independent of changes in the length of the tandem repeat element.