GENETIC-MAPPING OF 2 NEW BLOOD-PRESSURE QUANTITATIVE TRAIT LOCI IN THE RAT BY GENOTYPING ENDOTHELIN SYSTEM GENES

The endothelin system, consisting of a series of potent vasoconstricto r peptides and their receptors, is potentially important in the contro l of blood pressure. We found that the gene coding for endothelin-2 (E T2), also known as vasoactive intestine peptide, cosegregated strongly with systolic blood pressure in a F-2 population [F-2(S x LEW)] deriv ed from a cross of the Dahl salt-sensitive (S) rat and the Lewis (LEW/ NCrlBR) (LEW) rat. The ET2 locus was assigned to rat chromosome 5. The testis-specific histone (HITH) locus also strongly cosegregated with blood pressure in the F-2(S x LEW) population and was assigned to rat chromosome 17. Genetic maps of the regions containing the quantitative trait loci (QTL) for blood pressure on chromosomes 5 and 17 were cons tructed and the QTL were localized using the MAPMAKER/QTL program. The rat genes for endothelin-1, endothelin-3, and endothelin receptor A d id not cosegregate with blood pressure in several F-2 populations test ed and were assigned to rat chromosomes 17, 3, and 19, respectively. E ndothelin receptor B cosegregated weakly with blood pressure and was p rovisionally assigned to rat chromosome 15. We conclude that, in the r at, one new blood pressure QTL is located on chromosome 5 marked by th e ET2 locus and another new QTL is located on chromosome 17 near the H ITH locus.