ALLELES OF THE SPONTANEOUSLY HYPERTENSIVE RAT DECREASE BLOOD-PRESSUREAT LOCI ON CHROMOSOME-4 AND CHROMOSOME-13

In this study the spontaneously hypertensive rat (SHR/Mol) and the spo ntaneously diabetic BB/OK rat were crossed, and the Fl hybrids were ba ckcrossed onto the BB/OK rat in order to search for cosegregation betw een blood pressure and loci on chromosomes 4 and 13. Cosegregation of microsatellites on chromosomes 4 (Spr, Npy, D4mit6, Il-6) and 13 (Atp1 a2, D13Mit1, D13Uwm1) with blood pressure was evaluated using one-way analysis of variance. On chromosome 4 linkage of the Npy and D4Mit6 ma rkers to systolic blood pressure was observed. A blood pressure QTL wa s also found on chromosome 13 within the renin locus. Surprisingly, al leles of the SHR strain at loci showing linkage to blood pressure on c hromosome 4 and 13 promote lower blood pressure than the same alleles from the BB/OK strain. The transfer of D4Mit6 and renin locus from the SHR rat onto the genetic background of BB/OK rat will probably not le ad to a model of diabetic hypertension, but the thorough characterisat ion of such congenics could contribute to the explanation of genetics and pathophysiology of hypertension in the SHR rat. (C) 1997 Academic Press.