Independence of salt intake induced by calcium deprivation from the renin-angiotensin-aldosterone system.
We investigated whether the elevated NaCl intake shown by calcium-deprived rats is mediated by the renin-angiotensin-aldosterone system. First, we looked for manifestations of altered renin-angiotensin-aldosterone system activity during the progression of calcium deficiency. There were no differences between control and calcium-deprived rats in plasma aldosterone concentrations, plasma renin activity, plasma sodium concentrations, sodium balance, or blood pressure. Second, we used selective pharmacological antagonists to examine whether disruption of the renin-aldosterone-angiotensin system influenced salt intake. Blockade of aldosterone receptors with spironolactone (25 mg.kg-1 x day-1 sc for 7 days) had no effect on NaCl intake of control or calcium-deprived rats. Angiotensin AT1 receptor blockade with losartan potassium (0.5-10 mg/kg orally) had no effect on NaCl intake of control or calcium-deprived rats but doses > 0.5 mg/kg decreased NaCl intake of adrenalectomized rats. Taken together, these findings indicate that the renin-angiotensin-aldosterone system does not mediate the increased NaCl intake produced by calcium deficiency. The appetite for salt produced by calcium deficiency involves a different physiological substrate from most other models of NaCl intake.
Tordoff
M G
MG
Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104-3308.
Pilchak
D M
DM
Hughes
R L
RL
D000315:Adrenalectomy; D000450:Aldosterone / Q000097:blood*; D000804:Angiotensin II / Q000502:physiology*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001794:Blood Pressure; D002118:Calcium / Q000008:administration & dosage / Q000097:blood / Q000172:deficiency*; D004032:Diet; D008297:Male; D000451:Mineralocorticoid Receptor Antagonists / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000097:blood*; D012964:Sodium / Q000097:blood; D012965:Sodium Chloride / Q000008:administration & dosage*; D012982:Sodium, Dietary / Q000008:administration & dosage; D013148:Spironolactone / Q000494:pharmacology
D057911:Angiotensin Receptor Antagonists; D000451:Mineralocorticoid Receptor Antagonists; D012982:Sodium, Dietary; D000804:Angiotensin II; D013148:Spironolactone; D012965:Sodium Chloride; D000450:Aldosterone; D012964:Sodium; D012083:Renin; D002118:Calcium