Species differences between rat and rabbit renal Na+/H+ exchangers

Friedrich, Thomas; Sablotni, Jutta; Burckhardt, Gerhard

doi:10.1016/s0006-291x(87)80045-1

Cited by 15 publications

(3 citation statements)

References 12 publications

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“…3). The adult IC50 (3.1±0.7 3M) and the fetal ICM (6.5±0.3 AM) were similar and approximate the value previously reported for rabbit BBMV (4.7 AM [27]). Of note, at the highest concentration of EIPA employed, the maximal inhibition obtained at 1 mM Na+ was significantly less in fetal BBMV compared to adult [77.2±6.4% vs. 95.8±0.8%; P < 0.05].…”

Section: Resultssupporting

confidence: 88%

Ontogeny of Na/H antiporter activity in rabbit renal brush border membrane vesicles.

Beck¹,

Lipkowitz²,

Abramson³

1991

J. Clin. Invest.

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The development of the Na/H antiporter was studied in renal brush border membrane vesicles (BBMV) from fetal and adult rabbits using isotopic and fluorescent techniques. The kinetics of the antiporter studied by 'Na' uptake revealed that the V.,. was only 25% of that in the adult; however, the K.'s for Na'were not significantly different. These data were confirmed by a fluorescent assay using the pH-sensitive probe, acridine orange: the V.. was significantly lower in the fetal BBMV. Conductive Na' movement was estimated from amiloride-insensitive 22Na' uptake and the rate of alkalinization induced by K+, an ion whose relative conductance was found to be similar to that of Na'. Although relative Na' conductance was significantly greater in fetal BBMV, the lower V.,,, in fetal vesicles could not be ascribed to this factor. Maternal administration of betamethasone (50 ,ug/kg intramuscularly) for 2 d before delivery significantly increased the V.., of the antiporter to levels observed in the adult; K. was unaffected. Na/K ATPase activity increased fourfold after betamethasone, but the specific activities offour brush border marker enzymes and the kinetics of Na'-glucose cotransport were unchanged. These data indicate that there is a developmental increase in brush border Na/H exchange which is the result of an increase in the number and/ or the turnover number of the carriers. Further, these data suggest that the postnatal increase in antiporter activity may be related to the surge in glucocorticoid concentration that occurs perinatally. (J. Clin.

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Section: Resultssupporting

confidence: 88%

Ontogeny of Na/H antiporter activity in rabbit renal brush border membrane vesicles.

Beck¹,

Lipkowitz²,

Abramson³

1991

J. Clin. Invest.

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“…The apical antiporter exhibits low amiloride sensitivity (IC50 for the amiloride analogue ethylisopropylamiloride, -10 ,uM), whereas the basolateral transporter is very sensitive to ethylisopropylamiloride inhibition (IC5o -20 nM; 12). Thus, based on these inhibition kinetics, the apical form resembles the proximal tubule brush border Na/H antiporter, whereas the basolateral transporter behaves like the ubiquitous transporter found in many epithelial and nonepithelial cells (13). It was postulated, therefore, that LLC-PKl cells contain two different Na/H antiporters: a basolateral, "housekeeping" Na/H antiporter involved in cell pH defense and volume regulation, and an apical Na/H antiporter involved in transcellular proton/bicarbonate and possibly sodium transport.…”

Section: Introductionmentioning

confidence: 99%

Na/H antiporter mRNA expression in single nephron segments of rat kidney cortex.

Krapf¹,

Solioz²

1991

J. Clin. Invest.

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“…PLC cleaves phosphatidylinositol 4$biphosphate in inositol 1,4,5_triphosphate (IP,) and SIZ 1 ,Zdiacylglycerol (DG), which respectively release intracellular Ca*' ions [l] and activate protein kinase C (PKC) [2,3]. A second activating pathway is mediated via phospholipase A, (PLA,) and formation of prostaglandin endoperoxides/thromboxane A,, which induce platelet functions via a secondary, PLC-mediated mechanism [4,5].…”

Section: Introductionmentioning

confidence: 99%

α_2A‐Adrenergic receptors activate protein kinase C in human platelets via a pertussis toxin‐sensitive G‐protein

Nieuwiand¹,

Wijburg²,

Willigen³

et al. 1994

FEBS Letters

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Abstract4,4'-Diisothiocyanato-stilbene-2,2'-dlsulfonic acid (DIDS) stimulates human platelets via cc ,,-adrenerglc receptor-mediated activation of protein kmase C (PKC) independent of the phospholipase C pathway. Here we show, that in permeabilized platelets activation of PKC by DIDS (20 PM), measured as "P incorporation in pleckstrin, is completely inhibited by guanosine 5'-(2-0-thio)diphosphate (200 fiM), an inhibitor of heterotrimeric G-proteins. Also pertussin toxin (4 ,&ml), which ADP-ribosylates the a-subunits of G,'s and G,, prevents pleckstrin phosphorylation by DIDS. N-Ethylmaleimide (SOpM), which uncouples G, from a,,-adrenoceptors, inhibits pleckstrin phosphorylation by DIDS in intact platelets. Activation of PKC by 55 nM phorbol 12-myristate 13-acetate and 500 nM platelet-activating factor are not disturbed by NEM. DIDS inhibits by 40 f 5% (n = 4) the pertussis toxin-catalyzed ["P]ADP-ribosylation of a 41 kDa protein fraction previously shown to contain the a-subunits of G,a-1, G,a-2 and G,a-3. Thus, the a,,-adrenergic receptor activates PKC via a G-protein of the G,-family.

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Species differences between rat and rabbit renal Na+/H+ exchangers

Cited by 15 publications

References 12 publications

Ontogeny of Na/H antiporter activity in rabbit renal brush border membrane vesicles.

Ontogeny of Na/H antiporter activity in rabbit renal brush border membrane vesicles.

Na/H antiporter mRNA expression in single nephron segments of rat kidney cortex.

α_2A‐Adrenergic receptors activate protein kinase C in human platelets via a pertussis toxin‐sensitive G‐protein

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Species differences between rat and rabbit renal Na+/H+ exchangers

Cited by 15 publications

References 12 publications

Ontogeny of Na/H antiporter activity in rabbit renal brush border membrane vesicles.

Ontogeny of Na/H antiporter activity in rabbit renal brush border membrane vesicles.

Na/H antiporter mRNA expression in single nephron segments of rat kidney cortex.

α2A‐Adrenergic receptors activate protein kinase C in human platelets via a pertussis toxin‐sensitive G‐protein

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α_2A‐Adrenergic receptors activate protein kinase C in human platelets via a pertussis toxin‐sensitive G‐protein