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Dietary sodium and the renal responses to Angiotensin1–7 (ANG1–7)
Author(s) -
Johns Edward J,
Corbett Alan,
Albulushi Arif,
O'Neill Julie
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.812.19
Subject(s) - saline , endocrinology , medicine , chemistry , sodium , excretory system , excretion , renin–angiotensin system , natriuresis , kidney , diuresis , blood pressure , organic chemistry
This study investigated how the renal excretory actions of ANG1–7 were altered when the renin‐angiotensin system (RAS) was activated or suppressed following a period of low or high dietary sodium intake. Male Wistar rats were fed a low (0.03%), normal (0.3%) or a high (3.0%) sodium diet for 2 weeks. The animals were anaesthetised with chloralose/urethane and prepared for the measurement of blood pressure (BP), iv infusion of saline (0.9%NaCl, 3.0 ml/h). Cannulae were placed in the left ureter for urine collection and at the cortico‐medullary border for saline or ANG1–7 infusion at 1.0ml/h. Four 20 min clearances were taken, two before and two 45min after either saline or ANG1–7 (9×10 −7 M) infusion. Data, means ±SEM were analysed using Student's t test. Infusion of saline had no effect on BP or any renal functional parameter. ANG1–7 infusion in rats on the normal diet did not change BP, at 99±4mmHg, but urine flow, at 18.1±1.3μl/min/kg, and fractional sodium excretion (FENa), at 0.6±0.1, were increased by 24 and 25% (both P<0.05). In the low salt rats, ANG1–7 caused a greater response in FENa, of some 2–3 fold (P<0.05) whereas in the high salt rats, it was blunted, being only 60% of the response in normal rats. These findings demonstrate a dependency of the excretory responses to ANG1–7 on the endogenous levels of RAS.