Kinetics of triiodothyronine action on Na?K-ATPase in single segments of rabbit nephron

Barlet, C.; Doucet, Alain

doi:10.1007/bf00580716

Cited by 23 publications

(12 citation statements)

References 17 publications

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“…(b) The decrease in Na-K-ATPase activity observed in the CCT of TX rabbits was partially restored (up to 60%) 3 h after a single injection of T3 (50 Ag/kg body wt), as expected for the early response to T3 (2).…”

Section: Resultssupporting

confidence: 52%

“…This study was aimed at evaluating whether aldosterone is implicated in the early stimulation of Na-K-ATPase previously described in the CCT in response to the administration of T3 to thyroidectomized rabbits (2). It was initiated on the basis of the following observations: (a) Mineralocorticoids and thyroid hormones share similar intracellular mechanisms of action which consist in controlling expression of specific genes (1 1-14); (b) These hormones control the activity and the number ofcatalytic sites of Na-K-ATPase at the same sites in the kidney, the col- lecting tubule (1, 15); (c) They produce this control with similar kinetics (2,16) and, (d) Finally, aldosterone secretion rate (17) and plasma level (18) (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…It was initiated on the basis of the following observations: (a) Mineralocorticoids and thyroid hormones share similar intracellular mechanisms of action which consist in controlling expression of specific genes (1 1-14); (b) These hormones control the activity and the number ofcatalytic sites of Na-K-ATPase at the same sites in the kidney, the col- lecting tubule (1, 15); (c) They produce this control with similar kinetics (2,16) and, (d) Finally, aldosterone secretion rate (17) and plasma level (18) (Fig. 1) and, on the other hand, administration of large doses of aldosterone to TX rabbits mimicked the action of-T3 (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, within 1 wk thyroidectomy induces a marked decrease of the activity and number of catalytic sites of Na-K-ATPase in the proximal and collecting tubules exclusively (1). After administration of a physiologic dose of triiodothyronine to thyroidectomized rabbits, Na-K-ATPase was restored according to a biphasic pattern; an early increase was observed within 3 h, whereas the complete restoration up to control level occurred after 12-24 h (2). If the late response, observed in both proximal and collecting tubules is likely to correspond to the general action of thyroid hormones on Na-K-ATPase of most tissues (3)(4)(5)(6), the early response observed in the collecting tubule exclusively might result from another process.…”

Section: Introductionmentioning

confidence: 97%

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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: Resultssupporting

confidence: 52%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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

Barlet¹,

Doucet²

1987

J. Clin. Invest.

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“…Cl − /base exchange in neonatal and adult PST was not affected by cyanide and acetazolamide, CO 2 and bicarbonate, or the addition of formate, consistent with Cl − /OH − exchange (18,25). There was a sixfold maturational increase in apical membrane PST Cl − /OH − exchange activity (25).…”

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confidence: 55%

Maturation of proximal straight tubule NaCl transport: role of thyroid hormone

Shah¹,

Quigley²,

Baum

2000

American Journal of Physiology-Renal Physiology

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We have recently demonstrated that the rates of both active and passive proximal straight tubule (PST) NaCl transport in neonatal rabbits were less than in adults. In this segment NaCl entry across the apical membrane is via parallel Na + /H + and Cl − /OH − exchangers, which increases in activity with maturation. The present in vitro microperfusion study examined whether thyroid hormone plays a role in the maturational increase in PST NaCl transport. Neonatal and adult PST were perfused with a high-chloride-low bicarbonate solution without organic solutes, simulating late proximal tubule fluid. Thyroid hormone-treated neonates had a higher rate of PST total and passive NaCl transport. In 8-wk-old animals that were hypothyroid since birth, the maturational increase in total and passive NaCl transport was prevented. Thyroid treatment for 4 days in hypothyroid 8-wk-old rabbits increased the rate of both total and passive NaCl transport. The maturational increases in both Na + /H + and Cl − /OH − exchange activities were blunted in 8-wk-old hypothyroid animals and increased to control levels with thyroid treatment. This study demonstrates that thyroid hormone is a factor responsible for the maturational increase in both active and passive PST NaCl transport.Keywords sodium/hydrogen antiporter; chloride/base exchanger; kidney development; passive transportThe Proximal Tubule Reabsorbs ~60% of the filtered NaCl. The preferential reabsorption of organic solutes and bicarbonate by the early proximal tubule leaves the luminal fluid with a higher chloride and lower bicarbonate concentration than the peritubular plasma (19,24). In the proximal tubule approximately one-half of NaCl transport is passive and paracellular (4,25). The parallel operation of the apical membrane Na + /H + antiporter and Cl − /base exchangers mediate NaCl entry into the proximal tubule cell (1,18,25 We have recently examined the postnatal developmental changes in proximal straight tubule (PST) NaCl transport (25). In rabbit PST perfused with a high chloride-low bicarbonate solution simulating late proximal tubular fluid and bathed in a serum-like albumin solution, the rate of volume absorption, a reflection of both active and passive NaCl transport, was over twofold higher in the adult than neonatal segment (25). NaCl transport was inhibited by 50% by bath ouabain in adult tubules and totally inhibited in the neonatal segment. Thus the rates of active and passive NaCl transport were higher in the adult tubule than were those in the neonate (25).In the rabbit PST there was a fivefold increase in the Na + /H + antiporter activity during postnatal development (25). Cl − /base exchange in neonatal and adult PST was not affected by cyanide and acetazolamide, CO 2 and bicarbonate, or the addition of formate, consistent with Cl − /OH − exchange (18, 25). There was a sixfold maturational increase in apical membrane PST Cl − /OH − exchange activity (25).The factors that produce the profound postnatal changes in active and passive proximal tubular t...

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Biochemical Characterization of Individual Nephron Segments

Guder

Morel

1992

Comprehensive Physiology

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The sections in this article are: Biochemical Basis of Active Tubular Transport Biochemical Mechanisms of Hormone Action Cyclic AMP as Intracellular Messenger of Hormones Inositol Polyphosphates, Diacylglycerol, and Ca 2+ as Hormone Messengers Insulin and Growth Factors Action of Steroid Hormones Including Vitamin D Hormone Thyroid Hormones Biochemical Functions of the Proximal Tubule Coupling of Metabolism and Transport Brush‐Border Enzymes Renal Gluconeogenesis Amino Acid and Peptide Metabolism Biotransformation Reactions Thin Limbs of Henle's Loop Thick Ascending Limb of Henle's Loop Tamm‐Horsfall Glycoprotein The Distal Convoluted Tubule The Collecting Tubule Metabolism and Transport ATPases Organic Osmolytes

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Kinetics of triiodothyronine action on Na?K-ATPase in single segments of rabbit nephron

Cited by 23 publications

References 17 publications

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

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

Maturation of proximal straight tubule NaCl transport: role of thyroid hormone

Biochemical Characterization of Individual Nephron Segments

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