FAILURE OF ALLELES AT THE NA plus , K plus -ATPASE ALPHA-1 LOCUS TO COSEGREGATE WITH BLOOD-PRESSURE IN DAHL RATS

A previously described Pst I restriction fragment length polymorphism in Dahl rats at the Na+, K+ -adenosine 5′-triphosphatase (ATPase) α1 isoform locus was tested for cosegregation with blood pressure in segregating populations. Inbred Dahl salt-sensitive (S) and inbred Dahl salt-resistant (R) rats were crossed to produce F1 rats, and three segregating populations, F1 × R, F2 and F1 × S, were produced and raised on a high-salt diet for variable periods to attain the maximal blood pressure response in each population. In no segregating population was there a significant difference in blood pressure among genotypes at the Na+, K+ -ATPase α1 locus. Power calculations suggest that single-allele dosage effects of <7.5 mmHg were unlikely to be detected. It is concluded that either the S and R alleles at the Na+, K+ -ATPase α1 locus do not influence blood pressure under the conditions of these experiments (high dietary salt, Dahl rat genetic background) or, if they do, their effect is small. © Current Science Ltd.