Recruitment of the left ventricle for production of atrial natriuretic factor in Dahl salt-hypertension sensitive rats.

Dahl salt-sensitive (S) rats on normal salt intake develop a chronic form of hypertension with aging whereas Dahl salt-resistant (R) rats do not. In old hypertensive S rats the left ventricle is recruited for the production of ANF as evidenced by a seven- to ten-fold increase in atrial natriuretic factor (ANF) mRNA and increased ANF in ventricular tissue. Plasma ANF is also markedly increased in hypertensive S rats but there is no direct proof that ventricular production of ANF contributes to high plasma ANF. Atrial ANF is higher in S than R rats but this strain difference is not associated with strain differences in ANF mRNA in atria and atrial ANF mRNA does not increase dramatically in hypertensive S rats as does ventricular mRNA. Recruitment of the ventricle to produce ANF is clearly a secondary consequence of hypertension, but its functional significance is not established.