Atrial natriuretic factor in Dahl rats. Atrial content and renal and aortic responses.
Inbred Dahl salt-sensitive rats had a higher content of atrial natriuretic factor by bioassay in their atria than did inbred Dahl salt-resistant rats. This finding was true both in young 1- to 2-month-old rats, when blood pressure differences between strains were small, and in 7-month-old rats, when blood pressure differences were marked. Atria from salt-sensitive rats had more atrial natriuretic factor than did atria from salt-resistant rats when the rats were fed either low (0.3% NaCl) or high (8% NaCl) salt diet, but a high salt diet suppressed the atrial content of atrial natriuretic factor equally in both strains. In young, prehypertensive salt-sensitive rats, intravenous injections of atrial natriuretic factor caused significantly less natriuresis and diuresis than in salt-resistant rats (p less than 0.05). As the rats aged and salt-sensitive rats became markedly hypertensive, the strain responses to atrial natriuretic factor were reversed, that is, the salt-sensitive rats became more sensitive to atrial natriuretic factor than did the salt-resistant rats. Aortic vascular smooth muscle response to contraction with KCl was equally inhibited in both strains by atrial extracts or atriopeptin II. Thus, the salt-sensitive rat renal hyporesponsiveness to atrial natriuretic factor was not associated with a generalized hyporesponsiveness of vascular tissue to atrial natriuretic factor. It is argued that salt-sensitive rats could have two defects relating to atrial natriuretic factor, one involving hyporesponsive kidneys and another involving decreased release of atrial natriuretic factor from the atria.
Snajdar
R M
RM
Rapp
J P
JP
D000375:Aging; D000818:Animals; D001011:Aorta / Q000187:drug effects; D009320:Atrial Natriuretic Factor; D001808:Blood Vessels / Q000187:drug effects; D004032:Diet; D004305:Dose-Response Relationship, Drug; D007668:Kidney / Q000187:drug effects; D008297:Male; D009124:Muscle Proteins / Q000032:analysis* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains / Q000378:metabolism*; D012965:Sodium Chloride / Q000008:administration & dosage
D009124:Muscle Proteins; D012965:Sodium Chloride; D009320:Atrial Natriuretic Factor