title: Role of the renin-angiotensin system during alterations of sodium intake in conscious mice.
abstract: The present studies were performed to quantify circulating components of the renin-angiotensin-aldosterone axis and to determine the functional importance of this system during alterations in sodium intake in conscious mice. Increasing sodium intake from approximately 200 to 1,000 microeq/day significantly decreased plasma renin concentration from 472 +/- 96 to 304 +/- 83 ng ANG I. ml(-1). h(-1) (n = 5) but did not alter plasma renin activity from the low-sodium level of 7.7 +/- 1.1 ng ANG I. ml(-1). h(-1). Despite the elevated plasma renin concentration, plasma ANG II in mice on low-sodium level averaged 14 +/- 3 pg/ml and was significantly suppressed to 6 +/- 1 pg/ml by high-sodium intake (n = 7). Consistent with the modulation of ANG II, plasma aldosterone significantly decreased from 41 +/- 8 to 8 +/- 3 ng/dl when sodium intake was elevated (n = 6). In a final set of experiments, the continuous infusion of ANG II (20 ng. kg(-1). min(-1)) led to a mild salt-sensitive increase in mean arterial pressure from 108 +/- 2 to 131 +/- 2 mmHg as sodium intake was varied from low to high (n = 7). In vehicle-infused mice, mean arterial pressure was unaltered from 109 +/- 2 mmHg when sodium intake was increased (n = 6). These studies indicate that the physiological suppression of circulating ANG II may be required to maintain a constancy of arterial pressure during alterations in sodium intake in normal mice.
authors.affiliation: Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
authors.forename: B C
authors.initials: BC
authors.lastname: Cholewa
authors.forename: D L
authors.initials: DL
authors.lastname: Mattson
mesh_terms: D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000008:administration & dosage / Q000097:blood; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003243:Consciousness / Q000502:physiology*; D003404:Creatinine / Q000097:blood; D004573:Electrolytes / Q000097:blood; D005665:Furosemide / Q000494:pharmacology; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D008297:Male; D051379:Mice; D011188:Potassium / Q000097:blood; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology*; D012964:Sodium / Q000097:blood; D012982:Sodium, Dietary / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D004573:Electrolytes; D012982:Sodium, Dietary; D000804:Angiotensin II; D000450:Aldosterone; D005665:Furosemide; D012964:Sodium; D003404:Creatinine; D012083:Renin; D011188:Potassium