title: Distinct mechanisms of upregulation of type 1A angiotensin II receptor gene expression in kidney and adrenal gland.
abstract: We previously demonstrated that type 1A angiotensin II (Ang II) receptor (AT1A) is the predominant renal subtype and is upregulated by a low sodium diet. We have now tested the hypothesis that upregulation of AT1A mRNA induced by sodium deficiency is renal specific and is mediated by activation of type 1 Ang II receptor (AT1). Male Wistar rats were divided into four groups (n = 5 each) and treated for 2 weeks with normal sodium diet (0.5%), normal sodium plus 3 mg/kg per day losartan, low sodium diet (0.07%), or low sodium diet plus losartan. At the end of the 2 weeks, body weight and mean arterial pressure were not different among the four groups (P > .05). Plasma renin activity was elevated by losartan treatment, sodium restriction, or the combination of the two versus control (P < .05). Northern blot analysis showed that the ratio of renal AT1A to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA was increased by losartan treatment, sodium restriction, or the combination of the two versus control (P < .05). In contrast, the ratio of adrenal AT1A to GAPDH mRNA was increased only by sodium restriction versus three other groups (P < .05). Thus, sodium deficiency increases AT1A mRNA in both kidney and adrenal gland, while Ang II receptor blockade by losartan prevents low sodium-induced AT1A mRNA only in adrenal gland.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism*; D000704:Analysis of Variance; D000804:Angiotensin II / Q000235:genetics*; D000818:Animals; D001794:Blood Pressure; D015152:Blotting, Northern; D015342:DNA Probes; D018076:DNA, Complementary / Q000235:genetics; D007668:Kidney / Q000378:metabolism*; D008297:Male; D012313:RNA / Q000302:isolation & purification; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D011945:Receptors, Angiotensin / Q000235:genetics*; D012083:Renin / Q000097:blood; D015854:Up-Regulation
chemical_list: D015342:DNA Probes; D018076:DNA, Complementary; D012333:RNA, Messenger; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D012313:RNA; D012083:Renin