Age-related changes in secretion and metabolic effects of a trial natriuretic factor in rats.
The effects of aging on the secretion of and renal sensitivity to atrial natriuretic factor (ANF) were studied concomitantly in both senescent (25- to 34-month-old) and in adult (7- to 13 month-old) female and male Long-Evans rats. The plasma concentrations of ANF, measured in response to either a mild stimulation induced by a hypertonic volume expansion (i.e., 20 min after the onset of a continuous infusion during 15 min of a 2.5% NaCl solution; n = 18 old and 23 adult rats) or an intense stimulation produced by morphine injection (i.e., 30 min after an intraperitoneal injection of 5 mg morphine/100 g body weight; n = 11 old and 12 adult rats), were significantly lower (approximately -34 and -80%, respectively) in old as compared with adult animals. Acute intravenous injection of exogenous rat ANF (0.10 and 0.40 mu g/100 g body weight) induced similar natriuretic, diuretic, and kaliuretic effects in aged (n = 18) and in adult (n = 23) rats. The present data suggest that the significantly reduced (about -20%) natriuretic and kaliuretic responses of the aged rat, observed 20 min after the onset of hypertonic volume expansion, could be partly due to a primary defect in cardiac production and/or release of ANF rather than to a reduction of renal responsivity to ANF.
Rakotondrazafy
J
J
Laboratoire d'Endocrinologie Comparee, UFR de Biologie, Universite Bordeaux I, Talence, France.
Davicco
M J
MJ
Barlet
J R
JR
Brudieux
R
R
D000375:Aging / Q000378:metabolism*; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006982:Hypertonic Solutions / Q000008:administration & dosage / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology; D009294:Narcotics / Q000008:administration & dosage / Q000494:pharmacology; D009318:Natriuresis / Q000187:drug effects; D011188:Potassium / Q000652:urine; D011863:Radioimmunoassay; D051381:Rats; D012964:Sodium / Q000652:urine; D013268:Stimulation, Chemical
D006982:Hypertonic Solutions; D009294:Narcotics; D009020:Morphine; D009320:Atrial Natriuretic Factor; D012964:Sodium; D011188:Potassium