ISOLATION OF A CHROMOSOME-1 REGION THAT CONTRIBUTES TO HIGH BLOOD-PRESSURE AND SALT SENSITIVITY

Linkage analyses in the spontaneously hypertensive rat (SHR) suggest t hat a gene involved in blood pressure regulation may be located on rat chromosome 1, in the Sn region. To confirm this possibility, we repla ced a region of chromosome 1 in the Wistar-Kyoto rat (WKY) defined by the markers D1Mit3 and MTPA with the corresponding chromosome segment from SHR. Genotyping using 65 polymorphic microsatellite markers throu ghout the entire genome confirmed the congenic status of this new stra in designated WKY.SHR-D1Mit3/Rat57. In male WKY.SHR-D1Mit3/Rat57, mean blood pressures in the daytime and in the nighttime assessed by radio telemetry were significantly higher than those in male progenitor WKY. Moreover, salt loading significantly increased the mean blood pressur e in male WKY.SHR-D1Mit3/Rat57 but not in male progenitor WKY. The pre sent study confirmed the existence of a gene that contributes to high blood pressure and salt sensitivity in this chromosomal segment. This congenic strain represents a new animal model for fine mapping and cha racterization of the gene in this region involved in salt-sensitive hy pertension.