Renin-aldosterone axis and arginine-vasopressin responses to sodium depletion in camels.
Urinary output, urinary sodium and potassium excretion, plasma electrolyte concentrations and osmolality, plasma renin activity (PRA), and plasma aldosterone and arginine-vasopressin (AVP) concentrations were determined in eight camels in Tadla (Morocco). After administration of furosemide (2 mg.kg-1 body wt) urinary water, sodium and potassium excretions increased, inducing hypovolemia (as reflected by 14.6% increase in hematocrit), hyponatremia (142 +/- 1.0 vs 150 +/- 2.1 mmol.liter-1 in controls; P < 0.05), plasma hypo-osmolality (287.5 +/- 11.5 vs 307 +/- 1.4 mOsm.kg-1 H2O in controls; P < 0.05), and hypokalemia (3.7 +/- 0.2 vs 4.6 +/- 0.1 mmol.liter-1 in controls; P < 0.05). Such body fluid volume and composition changes were associated with parallel increases in PRA and plasma aldosterone concentrations (5.9 +/- 0.6 vs 0.9 +/- 0.2 ng AI.ml-1.hr-1 and 132.4 +/- 35.5 vs 25.1 +/- 6.5 pg.ml-1 in controls, respectively; P < 0.05). They were also associated with a fourfold increase in plasma arginine-vasopressin concentrations (0.8 +/- 0.2 vs 0.2 +/- 0.1 pg.ml-1; P < 0.05). In furosemide-treated animals, plasma aldosterone concentrations correlated positively with PRA (r = 0.85; n = 64; P < 0.01) and negatively with plasma sodium concentrations (r = -0.80; n = 64; P < 0.01), suggesting that in sodium-depleted camels the nexus between the renin-angiotensin system and aldosterone was restored.
Riad
F
F
Département de Biologie, Faculté des Sciences II, Université Hassan II, Casablanca, Morocco.
Ben Goumi
M
M
Giry
J
J
Davicco
M J
MJ
Safwate
A
A
Barlet
J P
JP
D000450:Aldosterone / Q000097:blood; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood*; D002162:Camelus / Q000378:metabolism*; D003681:Dehydration / Q000097:blood; D005260:Female; D005665:Furosemide / Q000494:pharmacology; D006400:Hematocrit; D009994:Osmolar Concentration; D011188:Potassium / Q000097:blood / Q000652:urine; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000502:physiology*; D012964:Sodium / Q000097:blood / Q000172:deficiency* / Q000652:urine; D014563:Urodynamics / Q000187:drug effects
D001127:Arginine Vasopressin; D000450:Aldosterone; D005665:Furosemide; D012964:Sodium; D012083:Renin; D011188:Potassium