Does age influence the blood pressure and sodium excretion responses to sodium depletion in rats?
Experiments were performed in 3- and 24-month-old male Wistar rats in order to assess the influence of age on the response by systolic blood pressure and sodium excretion to abrupt sodium restriction. In response to the sodium deprivation, urinary sodium excretion was markedly reduced in all animals; however, the cumulative sodium excretion (from days 1 to 6 of depletion) was significantly higher in aged rats (1299 +/- 243 mumol) than in young rats (757 +/- 70 mumol). After 6 days of a low-sodium diet, the systolic blood pressure was similar in both groups. Plasma renin activity was higher in young compared with aged rats (27 +/- 5 versus 14 +/- 3 ng/ml per h). These results indicate that ageing is associated with a significant disturbance in the renal but not the systemic response to an abrupt restriction in sodium intake.
Jover
B
B
Groupe Rein et Hypertension, Hôpital St Charles, Montpellier, France.
Varrault
A
A
Dupont
M
M
Mimran
A
A
D000375:Aging / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D004039:Diet, Sodium-Restricted; D008297:Male; D009318:Natriuresis / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood; D012964:Sodium / Q000008:administration & dosage* / Q000652:urine; D013997:Time Factors
D012964:Sodium; D012083:Renin