Ultrastructure of rat initial collecting tubule. Effect of adrenal corticosteroid treatment.

Stanton, Bruce A.; Janzen, A.; Klein-Robbenhaar, G.; DeFronzo, Ralph A.; Giebisch, Gerhard; Wade, James B.

doi:10.1172/jci111833

Cited by 55 publications

(25 citation statements)

References 34 publications

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“…A high K intake is a particularly powerful stimulus ofion transport across the collecting tubule epithelium, activating aldosterone release, Na reabsorption and K secretion, basolateral membrane amplification, and ATPase expression (8,9). Similar functional and morphological changes have also been Portions of this work have been published in abstract form (1986.…”

Section: Introductionmentioning

confidence: 89%

“…Microperfusion studies (1)(2)(3), electrophysiological experiments (4-7), and morphological (8)(9)(10) and enzyme analyses (11)(12)(13)(14)(15)(16) have identified the cortical collecting tubule of the rabbit as a key nephron site of regulation of Na and K transport. A high K intake is a particularly powerful stimulus ofion transport across the collecting tubule epithelium, activating aldosterone release, Na reabsorption and K secretion, basolateral membrane amplification, and ATPase expression (8,9).…”

Section: Introductionmentioning

confidence: 99%

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Effects of a high potassium diet on electrical properties of cortical collecting ducts from adrenalectomized rabbits.

Muto¹,

Sansom²,

Giebisch³

1988

J. Clin. Invest.

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The cortical collecting tubule is one of the main nephron sites where mineralocorticoids and a high potassium diet modulate sodium (Na) and potassium (K) transport. In this study we explored the steroid-independent effects of a high K diet on the electrical transport properties of the isolated rabbit cortical collecting tubule principal cells. The electrophysiological analysis included transepithelial and single-cell potential measurements and equivalent circuit analysis. Rabbits were adrenalectomized (ADX) and received either a control diet (300 meq K/kg diet) or a high K diet (600 meq/kg diet) for 10 d before the experiment. The mean plasma K of ADX control animals was 6.9 mM, that of ADX animals on the high K diet 8.3 mM. The transepithelial potential difference was significantly elevated in the high K group (-3.5 mV, lumen negative), compared with ADX controls (-1.4 mV). The basolateral membrane potential in high K animals was also significantly elevated (-73 mV, cell negative, compared with -63 mV in controls). Estimates of the apical membrane partial Na and K conductances (GN. and GIK) and of ion currents (INa and IK) also demonstrated stimulation by the high K diet. In the high K group, both GN. and GK (0.56 and 2.67 mS * cm-2) were higher than control values (0.27 and 1.17 mS. cm-2). INa and IK were also higher in high K animals (47.8 and -26.2 IA * cm-2) compared with control animals (22.4 and -11.6 AA * cm-2). Thus, a high K intake per se can induce electrophysiological changes consistent with stimulation of Na reabsorption and K secretion.

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Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Effects of a high potassium diet on electrical properties of cortical collecting ducts from adrenalectomized rabbits.

Muto¹,

Sansom²,

Giebisch³

1988

J. Clin. Invest.

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“…Kidneys were prepared for electron microscopy as described previously (1,26). Two to four initial collecting tubules, from each kidney, that were in contact with the renal capsule were selected for study.…”

Section: Methodsmentioning

confidence: 99%

“…Otherwise, preliminary inspection ofthe data was done by a one-way analysis of variance. Ifthere was a significant value ofFat P < 0.05, the Least Significant Difference test was used to identify statistical significance between means (25,26).…”

Section: Methodsmentioning

confidence: 99%

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Independent effects of aldosterone and potassium on induction of potassium adaptation in rat kidney.

Stanton¹,

Pan²,

Deetjen³

et al. 1987

J. Clin. Invest.

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We examined the independent effects of a high potassium diet and increased aldosterone levels on the development of renal potassium adaptation. This condition is defined by the increased ability of the kidneys to excrete an acute infusion of potassium. Rats were adrenalectomized (ADX) and received aldosterone at basal levels (0.5 Asg/100 g * d) or at high levels (2.0 ;g/100 go d) for 10 d. In each experimental group, animals received either a control diet or a high potassium diet. In ADX animals with basal aldosterone levels, a high potassium intake increased but did not completely restore the ability to excrete potassium and induced proliferation of the basolateral membrane of principal cells in the collecting tubule (i.e, morphologic adaptation). In contrast, increased aldosterone did not induce functional adaptation. Elevated aldosterone and dietary potassium intake were required to produce functional potassium adaptation indistinguishable from that in potassium-loaded, adrenal-intact animals.

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Decreased Adenosine Triphosphatase Activity in the Absence of Adrenocorticosteroids

Rarey

Tyneway²,

Patterson³

1989

Archives of Otolaryngology - Head and Neck Surgery

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\s=b\ Changes in adenosine triphosphatase activity and cellular integrity of rat innerear tissues were observed after removal of adrenal steroids via bilateral adrenalectomy. Statistical significance of total and magnesium ion-dependent adenosine triphosphatase activities of the stria vascularis, spiral ligament, and ampullar dark cells from adrenalectomized animals was detected when compared with those of controls as demonstrated by fluorometric microassay. Although there was a similar reduction of activity in utricular dark-cell tissues, no significant difference between the treated and control animals was observed. An increase of intercellular space and a decrease in basolateral infoldings of cells of the stria vascularis and dark cell regions of adrenalectomized animals were observed. Such data collectively provide indirect evidence that adrenal steroids are involved in the cellular regulation of inner-ear tissues that are concerned with fluid and ionic microhomeostasis.(Arch Otolaryngol Head Neck Surg. 1989;115:817-821) Adenosine triphosphatase (ATPase) has been demonstrated to be a vital enzyme in active transport mech¬ anisms of cells involved in ionic and fluid homeostasis throughout the body. Despite localization and quantitation of inner-ear ATPase by numerous investigators,18 regulation of such in¬ ner-ear activity remains an enigma. Recently, significant change in the sodium -potassium -ATPase (Na --ATPase) activity of selected inner-ear tissues was reported after bilateral adrenalectomy.9 Such data suggested that inner-ear microhomeostasis may be partially influenced by the effect of adrenal steroids on inner-ear ATPase activity.To define further inner-ear ATPase regulation by adrenal steroids, total and magnesium ion (Mg++)-dependent ATPase activities and cellular mor¬ phology of selected inner-ear tissues were determined. The hypothesis tested was that changes in serum levels of adrenal steroids can affect ATPases (eg, calcium and magnesium ions) other than Na-K-ATPase and can affect cellular features of certain inner-ear tissues, leading to fluid and ionic imbalance that may be associated with patients with inner-ear dysfunc¬ tion.The rationale of this investigation was based on the fact that the adrenal gland secretes mineralocorticoids (eg, aldosterone) and glucocorticoids (eg, Cortisol in humans and corticosterone in rats) (Fig 1). Mineralocorticoids af¬ fect ion-transporting epithelial cells by activating the transport of Na+ from the apical side to the vascular side and transport of K+ from the vas¬ cular side to the apical epithelial side. Glucocorticoids increase blood glucose concentration as well as affecting both plasma and fat metabolism. Both min¬ eralocorticoids and glucocorticoids are known to bind to receptor proteins and increase Na-K-ATPase activity.The approach used in this study was to remove endogenous steroids by bi¬ lateral adrenalectomy, thereby creat¬ ing a condition in which inner-ear en¬ zymatic activity and morphological changes could be examined in the ab¬ sence ...

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Ultrastructure of rat initial collecting tubule. Effect of adrenal corticosteroid treatment.

Cited by 55 publications

References 34 publications

Effects of a high potassium diet on electrical properties of cortical collecting ducts from adrenalectomized rabbits.

Effects of a high potassium diet on electrical properties of cortical collecting ducts from adrenalectomized rabbits.

Independent effects of aldosterone and potassium on induction of potassium adaptation in rat kidney.

Decreased Adenosine Triphosphatase Activity in the Absence of Adrenocorticosteroids

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