Regulation of L-leucine transport in rat kidney by dexamethasone and triiodothyronine

被引：0

作者：

M. Schwertfeger

K. Pissowotzki

Ch. Fleck

P. M. Taylor

机构：

[1] Institute of Pharmacology and Toxicology,

[2] University of Jena,undefined

[3] Germany,undefined

[4] ,undefined

[5] Department of Anatomy and Physiology,undefined

[6] University of Dundee,undefined

[7] Scotland,undefined

[8] United Kingdom,undefined

来源：

Amino Acids | 2003年 / 25卷

关键词：

Keywords: Amino acid transport; Kidney; Glucocorticoid hormones; Thyroid hormones; Leucine;

D O I：

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学科分类号：

摘要：

We have investigated the transport mechanisms involved in the stimulation of renal tubular reabsorption of large amino acids by glucocorticoids in vivo through the examination of activity and expression of specific transport systems L and y+L for L-leucine in membrane preparations of rat kidneys. Kidneys were removed from adult female Wistar rats treated with dexamethasone or triiodothyronine, and the fractions of brush-border and basolateral membranes were isolated by density gradient centrifugation. Functional analysis of L-leucine uptake using rapid filtration technique revealed induction of a sodium-dependent, arginine-inhibitable system y+L transport component in the basolateral membrane in the dexamethasone-treated group. A minor sodium-independent, BCH-inhibitable, system L transport component was unaffected by glucocorticoids. L-leucine uptake remained unaffected in the triiodothyronine-treated group. Expression of both subunits of the system y+L transporter was increased in dexamethasone-treated rat kidneys: Western blot analysis showed a significant (46%) increase of 4F2hc protein abundance in the basolateral membrane fraction and competitive RT-PCR revealed an almost 4-times induced expression of y+LAT1 mRNA. Our results indicate that system y+L in rat kidney is regulated by glucocorticoids. We suggest that enhancement of both 4F2 heavy chain and y+LAT1 light chain is necessary for induction of this transport system in the kidney.

引用

页码：75 / 83

页数：8

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