Sodium chloride and water transport in the thin descending limb of Henle of the quail

Nishimura, Hiroko; Koseki, Chizuko; Imai, Masashi; Braun, Eldon J.

doi:10.1152/ajprenal.1989.257.6.f994

Cited by 25 publications

(46 citation statements)

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“…If urea is added to the medullary interstitium, the osmolality can be further increased without increasing tonicity because urea evenly distributes to both extracellular and intracellular fluid. In fact, mammals can concentrate urine more effectively than lower class vertebrates such as reptiles or birds, which do not accumulate urea in the renal medulla (4,19).…”

Section: Discussionmentioning

confidence: 99%

Urea and NaCl regulate UT-A1 urea transporter in opposing directions via TonEBP pathway during osmotic diuresis

Kim

Kim²,

Lee³

et al. 2009

American Journal of Physiology-Renal Physiology

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Sands JM, Kim D. Urea and NaCl regulate UT-A1 urea transporter in opposing directions via TonEBP pathway during osmotic diuresis. Am J Physiol Renal Physiol 296: F67-F77, 2009. First published October 22, 2008 doi:10.1152/ajprenal.00143.2008.-In our previous studies of varying osmotic diuresis, UT-A1 urea transporter increased when urine and inner medullary (IM) interstitial urea concentration decreased. The purposes of this study were to examine 1) whether IM interstitial tonicity changes with different urine urea concentrations during osmotic dieresis and 2) whether the same result occurs even if the total urinary solute is decreased. Rats were fed a 4% high-salt diet (HSD) or a 5% high-urea diet (HUD) for 2 wk and compared with the control rats fed a regular diet containing 1% NaCl. The urine urea concentration decreased in HSD but increased in HUD. In the IM, UT-A1 and UT-A3 urea transporters, CLC-K1 chloride channel, and tonicity-enhanced binding protein (TonEBP) transcription factor were all increased in HSD and decreased in HUD. Next, rats were fed an 8% low-protein diet (LPD) or a 0.4% low-salt diet (LSD) to decrease the total urinary solute. Urine urea concentration significantly decreased in LPD but significantly increased in LSD. Rats fed the LPD had increased UT-A1 and UT-A3 in the IM base but decreased in the IM tip, resulting in impaired urine concentrating ability. The LSD rats had decreased UT-A1 and UT-A3 in both portions of the IM. CLC-K1 and TonEBP were unchanged by LPD or LSD. We conclude that changes in CLC-K1, UT-A1, UT-A3, and TonEBP play important roles in the renal response to osmotic diuresis in an attempt to minimize changes in plasma osmolality and maintain water homeostasis.UT-A3 urea transporter; CLC-K1 chloride channel; TonEBP transcription factor THE UT-A1 UREA TRANSPORTER plays a key role in urine concentration in mammals (21). In our previous studies, SpragueDawley rats made diabetic with streptozotocin had a great increase in UT-A1 abundance in both inner medullary (IM) base and tip to conserve water despite the ongoing osmotic diuresis (2, 12, 13). In contrast, diabetic Brattleboro rats (which lack vasopressin) did not increase UT-A1 protein abundance, and vasopressin-treated diabetic Brattleboro rats increased UT-A1 protein abundance more than nondiabetic vasopressintreated Brattleboros (14). This suggests that vasopressin and another factor (or factors) work together to increase UT-A1 abundance.Rats with NaCl diuresis induced by feeding of a high-salt diet also had a significant increase in UT-A1 abundance in both portions of the IM. However, rats with urea diuresis induced by feeding of urea did not increase UT-A1 abundance in either portion of IM, regardless of the severity of the osmotic diuresis (12). Rats with diabetes or NaCl diuresis have relatively decreased urea in the total urinary solute since the excretion of other solutes (glucose or NaCl) is increased, whereas rats fed a high-protein or -urea diet have an increase of urea in the total urinary solute, suggestin...

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Section: Discussionmentioning

confidence: 99%

Urea and NaCl regulate UT-A1 urea transporter in opposing directions via TonEBP pathway during osmotic diuresis

Kim

Kim²,

Lee³

et al. 2009

American Journal of Physiology-Renal Physiology

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“…PT proximal tubule AVT arginine vasotocin. Reproduced with modification from Nishimura et al [58] and Osono and Nishimura [62] ( Fig. 1).…”

Section: Functional Morphology Of Avian Kidney and Urine Concentrationmentioning

confidence: 99%

Urine concentration and avian aquaporin water channels

Nishimura

2008

Pflugers Arch - Eur J Physiol

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Although birds and mammals have evolved from primitive tetrapods and advanced divergently, both can conserve water by producing hyperosmotic urine. Unique aspects in the avian system include the presence of loopless and looped nephrons, lack of the thin ascending limb of Henle's loop, a corticomedullary osmotic gradient primarily consisting of NaCl without contribution of urea, and significant postrenal modification of final urine. The countercurrent multiplier mechanism operates between the descending and ascending limbs of Henle via recycling of a single solute (NaCl) with no water accompaniment, forming an osmotic gradient along the medullary cone. Bird kidneys and developing rat kidneys share morphological and functional characteristics. Avian kidneys express aquaporin (AQP) 1, 2, and 4 homologues that share considerable homology with mammalian counterparts, but their distribution and function may not be the same. AQP2 expression in Japanese quail (q) evolves in the collecting duct of early metanephric kidneys and continues to increase in intensity and distribution during nephrogenesis and maturation. qAQP2 mRNA and protein are increased by arginine vasotocin (avian ADH), but vasotocin-induced enhancement of cAMP production and water permeability are less marked than in mammalian kidneys. Nephrogenesis is delayed by insufficient nutrition in avian embryos and newborns and results in fewer nephrons and an impaired water balance in adults. Diabetes insipidus quail with homozygous autosomal recessive mutation and an unaffected vasotocin system have low AQP2 expression, underdeveloped medullary cones. Comparative studies will provide important insight into integrative, cellular, and molecular mechanisms of epithelial water transport and its control by humoral, neural, and hemodynamic mechanisms.

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“…They suggested a specific hypothesis for the operation of the avian concentrating mechanism, as a countercurrent multiplier system. They proposed that active transepithelial transport of sodium chloride from the thick epithelium of the ascending limb is the source of the single effect of the avian countercurrent mechanism (Nishimura et al 1989). The current study presents further information regarding the role of secretory units in urine production in some bird species.…”

Section: Discussionmentioning

confidence: 53%

“…Collecting ducts were separated by thick and thin loops of Henle throughout the medullary cones. Nishimura et al (1989) showed that the thin limb of the loop of Henle is operative in the countercurrent multiplication system. They suggested a specific hypothesis for the operation of the avian concentrating mechanism, as a countercurrent multiplier system.…”

Section: Discussionmentioning

confidence: 99%

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Stereological and electron microscopic study on the internal organization of the urinary secretory units in three species of birds

Dehkordi

Habibi

2014

Journal of Applied Animal Research

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Quantitative analysis of the kidney was undertaken in three species of bird: domestic fowl (Gallus domesticus), house sparrow (Passer domesticus) and domestic pigeon (Columba livia var. domestica). The volume and surface area of the renal components were measured. The fine structure of the proximal convoluted tubules showed intercellular spaces that were occupied by interdigitating folds at the basolateral membrane level. The distal tubules showed microvilli in the apical basement membrane into the tubular lumen. Microscopic study revealed that the domestic fowl had a greater volume of cortical tissue in the kidney compared with the other two species; this bird also had a greater medullary tissue volume than the other species. The volume and surface area of the renal corpuscles and proximal and distal convoluted tubules in the cortex were highest in the domestic fowl and lowest in the house sparrow. The volume and surface area of the proximal tubules, thin and thick limbs of the loop of Henle, and collecting ducts were lowest in the house sparrow, while the domestic pigeon had slightly higher values for these parameters. Blood capillaries in the domestic fowl had the greatest volume and surface area in the cortex and medulla. This study suggests that the volume and surface area in structural elements of the renal nephron in these birds play an important role in the concentration of urine.

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Sodium chloride and water transport in the thin descending limb of Henle of the quail

Cited by 25 publications

References 0 publications

Urea and NaCl regulate UT-A1 urea transporter in opposing directions via TonEBP pathway during osmotic diuresis

Urea and NaCl regulate UT-A1 urea transporter in opposing directions via TonEBP pathway during osmotic diuresis

Urine concentration and avian aquaporin water channels

Stereological and electron microscopic study on the internal organization of the urinary secretory units in three species of birds

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