HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 291/3/F597    most recent 00508.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Riazi, S. Articles by Ecelbarger, C. A. Search for Related Content PubMed PubMed Citation Articles by Riazi, S. Articles by Ecelbarger, C. A.

Aldosterone infusion with high-NaCl diet increases blood pressure in obese but not lean Zucker rats

¹Department of Medicine, Division of Endocrinology and Metabolism, and ²Center for the Study of Sex Differences in Health, Aging and Disease, Georgetown University, Washington, District of Columbia

Submitted 16 December 2005 ; accepted in final form 26 March 2006

Insulin-resistant, obese Zucker rats have blunted pressure natriuresis and are mildly hypertensive. This may involve inappropriate regulation of the renin-angiotensin-aldosterone system. To evaluate mechanisms underlying this defect, we employed the model of aldosterone escape. Male lean (L) and obese (O) Zucker rats were infused with aldosterone (2.8 µg/g body wt^3/4) via osmotic minipump while being fed a 0.02% NaCl diet (LS). After 4 days, six rats of each type were switched to a high-NaCl (HS) diet (4%) for 4 additional days. Mean arterial blood pressure measured by radiotelemetry was significantly increased by the HS diet only in obese rats (final mean mmHg): 104 (LLS), 99 (LHS), 103 (OLS), and 115 (OHS). Obese rats had relatively increased renal cortical abundance of the bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) and whole kidney - and -ENaC (epithelial sodium channel) relative to lean rats. However, band density for the thiazide-sensitive (Na-Cl) cotransporter (NCC) was similarly reduced by HS in lean and obese rats (50%). Obese rats had relatively reduced creatinine clearances and plasma renin activities, effects exacerbated by HS. Furthermore, HS resulted in a 129% increase in urinary nitrates plus nitrites excretion in lean rats and led to, in contrast, a 46% reduction in obese rats. Plasma sodium and potassium concentrations were increased by HS in obese but not lean rats. Thus we demonstrate an impaired response to aldosterone infusion in obese relative to lean Zucker rats. This impairment may involve increased sodium reabsorption via NKCC2 or ENaC, decreased glomerular filtration rate, and/or nitric oxide bioavailability.

kidney; epithelial sodium channel; natriuresis; diuresis; NaPi-2; sodium hydrogen exchanger type 3; Na-K-2Cl cotransporter; BSC1; TSC; NCC; aquaporin; Na-Cl cotransporter; hyperglycemia; proteomics

This article has been cited by other articles:

				V. K. Madala Halagappa, S. Tiwari, S. Riazi, X. Hu, and C. M. Ecelbarger Chronic candesartan alters expression and activity of NKCC2, NCC, and ENaC in the obese Zucker rat Am J Physiol Renal Physiol, May 1, 2008; 294(5): F1222 - F1231. [Abstract] [Full Text] [PDF]

				K. A. Griffin, H. Kramer, and A. K. Bidani Adverse renal consequences of obesity Am J Physiol Renal Physiol, April 1, 2008; 294(4): F685 - F696. [Abstract] [Full Text] [PDF]

				D. Z. I. Cherney, J. W. Scholey, D. C. Cattran, A. K. Kang, J. Zimpelmann, C. Kennedy, V. Lai, K. D. Burns, and J. A. Miller The effect of oral contraceptives on the nitric oxide system and renal function Am J Physiol Renal Physiol, November 1, 2007; 293(5): F1539 - F1544. [Abstract] [Full Text] [PDF]

				S. Tiwari, S. Riazi, and C. A. Ecelbarger Insulin's impact on renal sodium transport and blood pressure in health, obesity, and diabetes Am J Physiol Renal Physiol, October 1, 2007; 293(4): F974 - F984. [Abstract] [Full Text] [PDF]