Enhancement of Biosynthesis of Na,K-ATPase in the Toad Urinary Bladder by Aldosterone but Not T3

Geering, Käthi; Girardet, M.; Bron, Claude; Kraehenbuhl, J. P.; Rossier, Bernard C.

doi:10.1016/s0070-2161(08)60639-5

Cited by 14 publications

(19 citation statements)

References 5 publications

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“…This antagonism occurs through the occupancy of specific nuclear receptors to T3 (21) and, in the absence ofalterations ofthe rate of synthesis ofNa-K-ATPase (22), is probably brought about via induction and/or repression ofproteins which, in turn, interfere with the physiological action of aldosterone (23). Although the interaction between T3 and aldosterone described in amphibians is different from that depicted in the present paper, which may reflect differences between poikilotherms and homeotherms, its molecular basis might be similar in mammalians and amphibians.…”

Section: Discussionmentioning

confidence: 99%

Triiodothyronine enhances renal response to aldosterone in the rabbit collecting tubule.

Barlet¹,

Doucet²

1987

J. Clin. Invest.

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Since thyroid hormones and mineralocorticoids were observed to stimulate kidney Na-K-ATPase in similar sites and with similar time courses, this study was initiated to evaluate whether aldosterone is involved in the stimulation of Na-K-ATPase observed in collecting tubules 3 h after triiodothyronine (T3) administration to thyroidectomized (TX) rabbits. Results indicate that: (a) Plasma aldosterone level decreased markedly in TX rabbits but was not restored 3 h after T3 injection; (b) Early stimulation of Na-K-ATPase by T3 was abolished when plasma aldosterone level was suppressed by adrenalectomy or when aldosterone effects were blocked by spironolactone; (c) Administration of aldosterone to TX rabbits mimicked the action of T3; (d) Sensitivity of Na-K-ATPase to aldosterone markedly decreased after thyroidectomy. These results demonstrate an interaction between aldosterone and T3 in the control of Na-KATPase in the collecting tubule. Triliodothyronine enhances the sensitivity of Na-K-ATPase to aldosterone which, in turn, produces a stimulatory action despite the decreased plasma level observed during hypothyroidism.

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Section: Discussionmentioning

confidence: 99%

Triiodothyronine enhances renal response to aldosterone in the rabbit collecting tubule.

Barlet¹,

Doucet²

1987

J. Clin. Invest.

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“…Microsomes were prepared as described (20) and the immunoprecipitations were performed as described (21) under nondenaturing conditions, resolved by 5-8% gradient SDS-PAGE and revealed by fluorography. The polyclonal antibodies used were raised against the amino acids: 10 to 77 of the rat ␣ENaC subunit, 559 to 636 of the rat ␤ENaC subunit, and 570 to 650 of the rat ␥ENaC subunit (2).…”

Section: Methodsmentioning

confidence: 99%

Mutational Analysis of Cysteine-rich Domains of the Epithelium Sodium Channel (ENaC)

Firsov¹,

Robert-Nicoud²,

Gründer

et al. 1999

Journal of Biological Chemistry

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One of the characteristic features of the structure of the epithelial sodium channel family (ENaC) is the presence of two highly conserved cysteine-rich domains (CRD1 and CRD2) in the large extracellular loops of the proteins. We have studied the role of CRDs in the functional expression of rat ␣␤␥ ENaC subunits by systematically mutating cysteine residues (singly or in combinations) into either serine or alanine. In the Xenopus oocyte expression system, mutations of two cysteines in CRD1 of ␣, ␤, or ␥ ENaC subunits led to a temperaturedependent inactivation of the channel. In CRD1, one of the cysteines of the rat ␣ENaC subunit (Cys 158 ) is homologous to Cys 133 of the corresponding human subunit causing, when mutated to tyrosine (C133Y), pseudohypoaldosteronism type 1, a severe salt-loosing syndrome in neonates. In CRD2, mutation of two cysteines in ␣ and ␤ but not in the ␥ subunit also produced a temperaturedependent inactivation of the channel. The main features of the mutant cysteine channels are: (i) a decrease in cell surface expression of channel molecules that parallels the decrease in channel activity and (ii) a normal assembly or rate of degradation as assessed by nondenaturing co-immunoprecipitation of [35 S]methionine-labeled channel protein. These data indicate that the two cysteines in CRD1 and CRD2 are not a prerequisite for subunit assembly and/or intrinsic channel activity. We propose that they play an essential role in the efficient transport of assembled channels to the plasma membrane.The amiloride-sensitive epithelial sodium channel (ENaC) 1 belongs to the rapidly growing ENaC/DEG (degenerins) family of ion channels implicated in a variety of physiological functions. The specific tissue and species expression patterns of the channels allow us to classify them in four subfamilies: (i) ␣, ␤, and ␥ ENaC subunits, mainly expressed in epithelia; (ii) MDEG1, MDEG2, ASIC, and DRASIC genes, recently identified in the nervous system of mammals; (iii) FaNaCh involved in synaptic transmission in snail; (iv) MEC-4, MEC-10, DEG-1 (degenerins), and UNC 105 of the Caenorhabditis elegans nematode expressed in sensory neurons and muscles, respectively (1). All proteins of this supergene family share a common membrane topology with two transmembrane domains, short intracellular N and C termini and a large extracellular loop (2). An heterotetrameric structure has been recently proposed for ENaC (3, 4), whereas an homo-tetrameric structure has been proposed for FaNaCh (5). It is therefore likely that this gene family of cation channel is tetrameric, despite a study suggesting a nonameric architecture for ENaC (6).Structure-function studies performed on ENaC subunits have indicated some specific functional roles of different domains of the proteins. Schild et al. , an important mechanism controlling Na ϩ reabsorption (12). In intact cells (i.e. Xenopus oocytes) phosphorylation studies have also demonstrated a possible role of the C termini, as the target sequences for hormone-stimulated protein kinases A-and C-...

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“…At present, relatively little is known about this topic. Concerning upregulation, it has been shown that thyroid hormones in mammals (Lo & Edelmann, 1976;Lin & Akera, 1978), aldosterone in amphibia (Geering et al, 1982(Geering et al, , 1984 or salt stress in marine ducks (Hossler et al, 1978;Lingham et al, 1980) stimulate the biosynthesis of Na,K-ATPase molecules and their insertion into the plasma membrane.…”

Section: Receptor Recyclingmentioning

confidence: 99%

The receptor function of the Na+, K+-activated adenosine triphosphatase system

Anner¹

1985

Biochemical Journal

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Enhancement of Biosynthesis of Na,K-ATPase in the Toad Urinary Bladder by Aldosterone but Not T3

Cited by 14 publications

References 5 publications

Triiodothyronine enhances renal response to aldosterone in the rabbit collecting tubule.

Triiodothyronine enhances renal response to aldosterone in the rabbit collecting tubule.

Mutational Analysis of Cysteine-rich Domains of the Epithelium Sodium Channel (ENaC)

The receptor function of the Na+, K+-activated adenosine triphosphatase system

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