Partial characterization of atrial natriuretic factor in the hearts of Dahl salt-sensitive and salt-resistant rats.

Atria of adult Dahl salt-sensitive rats contain more atrial natriuretic factor (ANF) than those of Dahl salt-resistant rats, as measured by RIA. This strain difference was not seen at 15 days of age, but was observed at and after 30 days of age. Neither a sodium-deficient diet nor an 8% NaCl diet started as early as 2 weeks of age altered this strain difference, although high dietary NaCl was associated with reduced atrial ANF concentration. In addition, no qualitative differences were found in the S and R ANF precursor, as assessed by 1) in vitro translation of atrial mRNA followed by immunoprecipitation of the ANF precursor and polyacrylamide gel electrophoresis, and 2) fractionation of S and R atrial extracts by reverse phase HPLC. These findings support the view that the S vs. R strain difference in atrial ANF concentration is more likely to arise from genetic control of regulatory phenomena than from alterations in the structural part of the ANF gene.