Delineation of Cystine and Cysteine Transport Systems in Rat Kidney Cortex by Developmental Patterns

Segal, Stanton; Smith, Inez

doi:10.1073/pnas.63.3.926

Cited by 30 publications

(10 citation statements)

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“…They found that the intracellular form after cystine transport was cysteine (100%). This was later re-examined in both 5-day old and adult rat kidney tissue using a TLC technique (14). Cysteine was again found to be the primary intracellular cystine metabolite (51-68%) but a substantial amount of 'sS incorporation into reduced glutathione (12-30%) was also noted in both groups using this method.…”

Section: Discussionmentioning

confidence: 91%

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Cellular Accumulation of L-Cystine in Rat Kidney Cortex In Vivo

Greth¹,

Their²,

Segal³

1973

J. Clin. Invest.

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A B S T R A C T Cellular accumulation of L-cystine in rat kidney cortex in vivo has been studied using L- [ ¶S] cystine. The L-[US]cystine radioactivity in plasma decreases to less than 10% of the initially calculated value by 15 min. Four 'S-containing intracellular products of L-cystine metabolism were identified including cystine, cysteine, reduced glutathione, and an as yet unidentified compound. The latter is probably taurine, cysteinesulphinate, or cysteic acid. Cellular accumulation of these products was found to be more rapid in vivo than in vitro. Cellular accumulation of the products of Lcystine metabolism was found to be essentially un-

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Section: Discussionmentioning

confidence: 91%

“…Kinetic (12) and ontogenetic (14) studies in rat kidney cortex in vitro provide strong evidence that systems for cellular accumulation of cystine and cysteine are different. No interaction between cysteine and the dibasic amino acids for entry into tubule cells has been found (15).…”

Section: Introductionmentioning

confidence: 99%

Cellular Accumulation of L-Cystine in Rat Kidney Cortex In Vivo

Greth¹,

Their²,

Segal³

1973

J. Clin. Invest.

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“…To examine these mechanisms, developmental studies of cystine transport have utilized several in vitro renal cortical tissue preparations. In earlier experiments cystine uptake by rat renal cortical slices was examined (13,16,19,20), but the cortical slice has been shown to provide an inadequate picture of cystine transport mechanisms (13,14,17). Isolated renal tubule fragments, however, offer a more complete view of the processes involved (13,14).…”

Section: Resultsmentioning

confidence: 99%

Developmental Aspects of Cystine Transport in the Dog

et al. 1986

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ABSTRACT. Developmental changes in cystine transport occurs is during the newborn period. This "physiological" cystinby the canine kidney were examined both in vivo and in uria of the normal newborn has been noted in a number of vitro. Renal clearance studies indicated that cystine was animal species, including man (1 8). There is evidence that sugone of the more incompletely reabsorbed amino acids at gests that there is increased cystine excretion in the newborn dog birth, but its reabsorption approaches adult levels by 21 (6). Therefore, studying cystine transport in the immature dog days. Concomitantly, cystine uptake by isolated renal cor-where reabsorption is incomplete may offer insights into mechtical tubule fragments from immature dogs was slower than anisms responsible for the inherited abnormality and give inforthat by renal tubules from adult dogs. Both age groups mation concerning the nature of changes in renal amino acid rapidly metabolized the transported cystine. This metabo-transport with maturation. Because of this we have examined lism was principally to cysteine, but also small amounts of cystine handling by the kidney of the developing dog in vivo and reduced glutathione were formed from the transported by isolated renal cortical tubular fragments in vitro. cystine. Concentration dependence studies indicated two transport systems for cystine uptake in both the immature and the adult dog. Both transport systems in the 1-wk-old MATERIALS AND METHODS dog had a somewhat greater affinity for c~s t i n e than theThe renal clearance of amino acids was measured in 17 moncorresponding system in the adult, but this was offset by grel dogs of either sex at various ages: 5 days, 21 days, 8 wks, 12 the markedly lower maximal rates for these wks, and greater than a year using methods previously described systems in the l-wk-O'dThe high affinity system was (2,7,8). The amino acid clearance and glomerular filtration rate hhibited by lysine in tubules age groups. In the were measured simultaneously, the latter by the renal clearance dog, the rise in the tubular reabsorption of c~s t i n e with of inulin and endogenous creatinine. The 8-and 12-wk pups maturation could, in part, be explained by an increase in were maintained on a standard commercial diet and fasted for

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“…Lower distribution ratios were found after 120 min for glycine, leucine, and glutamic acid, but lysine and a-AIB accumulation were still increasing in a linear fashion after this interval. Segal and Smith (31,32) showed that lysine uptake was similar in neonatal and adult cortex dices, but cystine uptake was decreased and did not reach adult levels until age 2-wk. However, lysine accumulation was much less sodium-dependent than in adult tissue; cystine accumulation was actually more sodium-dependent.…”

Section: Discussionmentioning

confidence: 98%

Developmental Aspects of Renal β-Amino Acid Transport I. Ontogeny of Taurine Reabsorption and Accumulation in Rat Renal Cortex

Chesney

Jax

1979

Pediatr Res

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Summaryevidence that breast milk is a dietary source of taurine in the weanling rat, several studies have suggested fully developed tauNewborn Sprague-Dawley rat pups were found t' have reduced rine synthetic capacity in the neonatal rat in contrast to the net tubular reclamation of the p-amino acid taurine in vivo. The ,itUation in man (34,35). reabsorption of this compound increased between the 2nd and 4thThe renal uptake of taurine both in viva and in vitro has been week of life and the excreted taurine fell despite a rise in glomer-defined in adult mouse (10) and in adult rat kidney cortex (7, 9). ular filtration rate indicative of increased transport with matura-Endogenous clearance of tauhe in rat may be as high as 40% tion.(19), but most studies utilizing free flow micropuncture (13) or cortex in viva taurine from plasma against continuous microperfusion (1 1) have consistently found a cleara large chemical gradient. Newborn cortex slices in vitro accu-ance of s% of filtered load, a value akin to that found in A,J mutated taurine to higher levels at steady state at 4 . 4 mM, but mouse (10). ~h~ t a u h e reabsorptive system, in contrast to net uptake was less efficient at higher taurine concentrations. Further reclamation for most a-amino acids, demonstrates a high cortex 'Iices was not found at any age. but low capacity for uptake; thus, reabsorption of only 9&95% of in and newborn was greatest at filtered load has been found (9,11,30). Uptake by cortex slices, mEq/liter K in the external medium. Slices from younger animals indicative .of antiluminal membrane transport (41, 421, took place had 'lightly higher pH 'ptima for 'ptake and temperature by at least two t a u h e carriers in both mouse and rat (7, 9, 10). tion increases uptake more in neonatal than in adult kidney.Each site was sodium-dependent, required aerobic metabolism, and, of all amino acids tested, only /?-amino acids, such as /?-Speculation alanine, prevented taurine uptake in a competitive fashion (9, 10, If the newborn rat is in part dependent on the transfer of taurine 16). Glutathione oxidation inhibited taurine accumulation by the from mother to pup via milk, the process of weaning may require first (low Km, high affinity) transport system possibly by enhanced greater renal tubular reabsorption in order to maintain tissue and taurine efflux (7, 9). The pattern of taurine excretion and the plasma pools of taurine. The improved reabsorption of taurine tissue levels of this amino acid over the first few weeks of life found in 4-week-old and adult animals may reflect maturational be to the Ontogeny of changes brought about by the reduction in dietary taurine (and mechanisms, particularly because amino acid hyperexcretion is other sulfur containing amino acids) after weaning. characteristic of the early postnatal period in man and other mammals (1, 30). In this paper, the authors discuss the development of the in vivo taurine renal transport system during the first Taurine (2-aminoethanesulfonic acid), the amino acid charac-month of life....

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Delineation of Cystine and Cysteine Transport Systems in Rat Kidney Cortex by Developmental Patterns

Cited by 30 publications

References 14 publications

Cellular Accumulation of L-Cystine in Rat Kidney Cortex In Vivo

Cellular Accumulation of L-Cystine in Rat Kidney Cortex In Vivo

Developmental Aspects of Cystine Transport in the Dog

Developmental Aspects of Renal β-Amino Acid Transport I. Ontogeny of Taurine Reabsorption and Accumulation in Rat Renal Cortex

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