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Efficient oxygen utilization in the kidney may be supported by paracellular epithelial transport, a form of passive diffusion that is driven by preexisting transepithelial electrochemical gradients. Claudins are tight-junction transmembrane proteins that act as paracellular ion channels in epithelial cells. In the proximal tubule (PT) of the kidney,(More)
The sodium pump Na,K-ATPase, located in the plasma membrane of all animal cells, is a member of a family of ion-translocating ATPases that share highly homologous catalytic subunits. In this family, only Na,K-ATPase has been established to be a heterodimer of catalytic (alpha) and glycoprotein (beta) subunits. The beta subunit has not been associated with(More)
Fourteen-day adrenal steroid treatment increases [(3)H]ouabain binding sites 22-48% in muscle biopsies from patients treated with adrenal steroids for chronic obstructive lung disease and in rats treated with dexamethasone (Dex). Ouabain binding measures plasma membrane sodium pumps (Na(+)-K(+)-ATPase) with isoform-dependent affinity. In this study we have(More)
The purpose of this study was to determine the pattern of thyroid hormone (triiodothyronine, T3) regulation of the Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase) alpha- and beta-subunit expression in skeletal muscle, which expresses alpha 1-, alpha 2-, beta 1-, and beta 2-subunits, and compare it with that seen in kidney, which expresses only alpha(More)
Effects of chronic nicotine treatment on the relative levels of expression of Na,K-ATPase alpha and beta subunit isoforms were determined in rat cerebral microvessels and capillary-depleted brain homogenates by Western blot analysis. Nicotine, 4.5 mg/kg/day, was administered s.c. by osmotic mini-pumps for 14 days. Expression of alpha 2 isoform in(More)
OBJECTIVES AND METHODS Guanylin and uroguanylin are peptides synthesized in the intestine and kidney that are postulated to have both paracrine and endocrine functions, forming a potential enteric-renal link to coordinate salt ingestion with natriuresis. To explore the in vivo role of guanylin and uroguanylin in the regulation of sodium excretion, we used(More)
Extracellular K(+) concentration ([K(+)]) is closely regulated by the concerted regulatory responses of kidney and muscle. In this study, we aimed to define the responses activated when dietary K(+) was moderately reduced from a control diet (1.0% K(+)) to a 0.33% K(+) diet for 15 days. Although body weight and baseline plasma [K(+)] (4.0 mM) were not(More)
We previously reported that Na(+)/H(+) exchanger type 3 (NHE3) and NaPi2 are acutely retracted from the proximal tubule (PT) microvilli (MV) during acute hypertension [high blood pressure (BP)] or parathyroid hormone (PTH) treatment. By subcellular membrane fractionation, NHE3 and NaPi2 show indistinguishable redistribution patterns out of light-density(More)
Acute hypertension provokes a rapid decrease in proximal tubule sodium reabsorption with a decrease in basolateral membrane sodium-potassium-ATPase activity and an increase in the density of membranes containing apical membrane sodium/hydrogen exchangers (NHE3) [Y. Zhang, A. K. Mircheff, C. B. Hensley, C. E. Magyar, D. G. Warnock, R. Chambrey, K.-P. Yip, D.(More)
Acute arterial hypertension provokes a rapid decrease in proximal tubule (PT) Na+ reabsorption, increasing flow to the macula densa, the signal for tubuloglomerular feedback. We tested the hypothesis, in rats, that Na+ transport is decreased due to rapid redistribution of apical Na+/H+ exchangers and basolateral Na+ pumps to internal membranes. Arterial(More)