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Increased glomerular angiotensin II binding in rats exposed to a maternal low protein diet in utero
Author(s) -
Sahajpal Vandana,
Ashton Nick
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2004.078642
Subject(s) - endocrinology , medicine , angiotensin ii , renin–angiotensin system , offspring , receptor , aldosterone , angiotensin receptor , in utero , in vivo , chemistry , plasma renin activity , biology , blood pressure , pregnancy , fetus , genetics , microbiology and biotechnology
In the rat, protein restriction during pregnancy increases offspring blood pressure by 20–30 mmHg. We have shown in an earlier study that this is associated with a reduction in nephron number and increased glomerular sensitivity to angiotensin II (Ang II) in vivo . Hence, we hypothesized that exposure to a maternal low‐protein diet increases glomerular Ang II AT 1 receptor expression and decreases AT 2 receptor expression. To test this hypothesis, pregnant Wistar rats were fed isocalorific diets containing either 18% (control) or 9% (LP) protein from conception until birth. At 4 weeks of age, the kidneys of male offspring were harvested to measure cortical AT 1 and AT 2 receptor expression, 125 I‐Ang II glomerular binding, tissue renin activity, tissue Ang II and plasma aldosterone concentrations. AT 1 receptor expression was increased (62%) and AT 2 expression was decreased (35%) in LP rats. Maximum 125 I‐Ang II ( 125 I‐Ang II) binding ( B max ) was increased in LP rats (control n = 9, 291.6 ± 27.4 versus LP n = 7, 445.7 ± 27.4 fmol (mg glomerular protein) −1 , P < 0.01), but affinity ( K D ) was not statistically different from controls (control 2.87 ± 0.85 versus LP 0.84 ± 0.20 pmol 125 I‐Ang II, P = 0.059). Renal renin activity, tissue Ang II and plasma aldosterone concentrations did not differ between control and LP rats. Increased AT 1 receptor expression in LP rat kidneys is consistent with greater haemodynamic sensitivity to Ang II in vivo . This may result in an inappropriate reduction in glomerular filtration rate, salt and water retention, and an increase in blood pressure.