scholarly journals QUANTITATIVE HISTOCHEMISTRY OF URIDINE DIPHOSPHOGLUCOSE-PYROPHOSPHATASE AND URIDINE DIPHOSPHOGLUCOSE-PYROPHOSPHORYLASE IN DEVELOPING RAT KIDNEY

1974 ◽  
Vol 22 (11) ◽  
pp. 1034-1038 ◽  
Author(s):  
CLINTON N. CORDER ◽  
MARK L. BERGER ◽  
OLIVER H. LOWRY
Keyword(s):  
Rat Kidney ◽  
Development Activity ◽  
Quantitative Histochemistry ◽  
Small Arteries ◽  
Straight Tubule ◽  
Adult Kidney ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Developing Rat ◽  
Made In

Quantitative histochemical measurements of two enzymes of uridine diphosphoglucose (UDPG) metabolism have been made in the developing rat kidney nephron. Kidneys were examined from -4 days to 44 days of age. In the adult kidney, UDPG-pyrophosphatase was concentrated in proximal convoluted and straight tubules. During maturation, activity decreased in glomeruli, increased in the proximal tubule and changed little elsewhere in the nephron. UDPG-pyrophosphorylase revealed a different pattern. Activity was more nearly uniformly distributed throughout the nephron but was highest in the proximal straight tubule and ascending limb of Henle. During development, activity was unchanged or increased in glomeruli and small arteries and increased elsewhere, particularly in the proximal straight tubule and ascending limb of Henle.

Transport of potassium in the rabbit pars recta

1982 ◽  
Vol 242 (3) ◽  
pp. F226-F237 ◽  
Author(s):  
J. Work ◽  
S. L. Troutman ◽  
J. A. Schafer
Keyword(s):  
Bathing Solution ◽  
Passive Permeability ◽  
Straight Tubule ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Pars Recta ◽  
K Secretion ◽  
Unidirectional Fluxes ◽  
K Concentration ◽  
K Permeability

Unidirectional fluxes of 42K+ and 86Rb+ were measured in isolated perfused segments of proximal straight tubules and no differences were found between the two isotopes for the same flux determination. In the three segments examined (the early and late superficial proximal straight tubule and the juxtamedullary proximal straight tubule) there was apparent net active K+ secretion as demonstrated by differences in the unidirectional fluxes of 2.6, 3.2, and 4.8 pmol.min-1.mm-1, respectively. However, in contrast to the expectations for active K+ secretion, the bath-to-lumen fluxes were unaffected by 0.1 mM ouabain added to the bathing solution, and in the early superficial and juxtamedullary segments these fluxes were directly proportional to the K+ concentration of the bathing solution over a range of concentrations. Apparent K+ permeability coefficients were calculated from lumen-to-bath fluxes to be 0.14 +/- 0.02, 0.10 +/- 0.02, and 0.52 +/- 0.07 micrometers.s-1 in the early and late superficial and juxtamedullary segments, respectively. Based on these data and on a mathematical analysis, we have concluded that active K+ secretion of the magnitude measured would have little importance in determining the K+ load delivered to the descending limb of the loop of Henle. However, the higher passive permeability of the juxtamedullary segment would allow significant net K+ secretion if the outer medullary interstitium had even a moderately elevated K+ concentration.

Inhibition of Jv by ANF in rat proximal straight tubules requires angiotensin

1989 ◽  
Vol 257 (5) ◽  
pp. F907-F911 ◽  
Author(s):  
J. L. Garvin
Keyword(s):  
Angiotensin Ii ◽  
Atrial Natriuretic Factor ◽  
Second Messenger ◽  
Fluid Absorption ◽  
Straight Tubule ◽  
Cyclic Monophosphate ◽  
Natriuretic Factor ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Messenger System

The effects of atrial natriuretic factor (ANF) on fluid absorption (Jv) by isolated perfused proximal straight tubules of rats were investigated. ANF alone (10(-8) M) added to the bath had no significant effect on absorption. In contrast, when tubules were first treated with 1.6 X 10(-10) M angiotensin II, this same concentration of ANF lowered fluid absorption from 0.99 +/- 0.03 to 0.69 +/- 0.02 nl.mm-1.min-1. A lower dose of ANF, 2 X 10(-10) M, reduced fluid absorption in the presence of angiotensin II from 1.13 +/- 0.06 to 0.65 +/- 0.05 nl.mm-1.min-1, an inhibition of 40%. Since guanosine 3',5'-cyclic monophosphate (cGMP) is reportedly part of the second messenger system of ANF, the effects of dibutyryl-cGMP (DBcGMP) on fluid absorption were studied. This membrane-permeant form of cGMP mimicked the effects of ANF, reducing fluid absorption from 1.15 +/- 0.18 to 0.54 +/- 0.08 nl.mm-1.min-1. These studies suggested the following: 1) ANF can regulate fluid absorption in the proximal nephron; 2) this inhibition occurs only in the presence of angiotensin; and 3) cGMP is part of the second messenger system of ANF in the rat proximal straight tubule, as it is in other tissues.

Bicarbonate and ammonia transport in isolated perfused rat proximal straight tubules

1987 ◽  
Vol 253 (2) ◽  
pp. F277-F281 ◽  
Author(s):  
J. L. Garvin ◽  
M. A. Knepper
Keyword(s):  
Fluid Transport ◽  
Distal Tubule ◽  
Co2 Absorption ◽  
Straight Tubule ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Total Ammonia ◽  
The Mean ◽  
Disequilibrium Ph

Bicarbonate, ammonia, and fluid transport were studied in isolated perfused proximal straight tubules from rats. The mean rate of fluid absorption (0.77 nl X min-1 X mm-1) and the mean rate of total CO2 absorption (42 pmol X min-1 X mm-1) exceeded corresponding rates measured previously in rabbit proximal straight tubules. The limiting total CO2 concentration when the tubules were perfused at slow flow rates was 5 mM, a value similar to those reported previously for rat proximal convoluted tubules and thick ascending limbs. When rat proximal straight tubules were perfused and bathed with solutions containing 1 mM total ammonia at slow perfusion rates, the measured total ammonia concentration in collected fluid rose to a level predicted by the diffusion trapping model of ammonia secretion in the absence of a luminal disequilibrium pH. We conclude the proximal straight tubule of the rat can absorb bicarbonate at a rate that can account for a large portion of the bicarbonate absorption measured in vivo between the late proximal convoluted tubule and the early distal tubule, the rat proximal straight tubule is capable of transepithelial ammonia secretion, most likely by NH3 diffusion down a concentration gradient generated by luminal acidification, and the rat proximal straight tubule apparently does not generate a luminal disequilibrium pH despite the occurrence of proton secretion, implying the presence of endogenous luminal carbonic anhydrase.

scholarly journals Maturation of rabbit proximal straight tubule chloride/base exchange

1998 ◽  
Vol 274 (5) ◽  
pp. F883-F888 ◽  
Author(s):  
Mehul Shah ◽  
Raymond Quigley ◽  
Michel Baum
Keyword(s):  
Adult Rabbit ◽  
Albumin Solution ◽  
Nacl Transport ◽  
Base Exchange ◽  
Straight Tubule ◽  
Volume Absorption ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Proximal Tubular

The present in vitro microperfusion study compared the mechanism and rates of NaCl transport in neonatal and adult rabbit proximal straight tubules. In proximal straight tubules perfused with a late proximal tubular fluid and bathed in a serumlike albumin solution, the rate of volume absorption ( J V) was 0.54 ± 0.10 and 0.12 ± 0.05 nl ⋅ mm−1 ⋅ min−1in adults and neonates, respectively ( P < 0.05). With the addition of 10−5 M bath ouabain, J Vdecreased to 0.27 ± 0.07 and −0.03 ± 0.04 nl ⋅ mm−1 ⋅ min−1in adult and neonatal tubules, respectively ( P < 0.05), consistent with lower rates of active and passive NaCl transport in the neonatal proximal straight tubule. The effect of luminal sodium and chloride removal on intracellular pH was used to assess the relative rates of Na+/H+and Cl−/base exchange. The rates of Na+/H+and Cl−/base exchange were approximately fivefold less in neonatal proximal straight tubules than adult tubules. In both neonatal and adult proximal straight tubules, the rate of Cl−/base exchange was not affected by formate, bicarbonate, or cyanide and acetazolamide, consistent with Cl−/OH−exchange. These data demonstrate an increase in proximal straight tubule NaCl transport during postnatal renal development.

Defective water and glycerol transport in the proximal tubules of AQP7 knockout mice

2005 ◽  
Vol 289 (6) ◽  
pp. F1195-F1200 ◽  
Author(s):  
Eisei Sohara ◽  
Tatemitsu Rai ◽  
Jun-ichi Miyazaki ◽  
A. S. Verkman ◽  
Sei Sasaki ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Water Channel ◽  
Physiological Role ◽  
Wild Type ◽  
Double Knockout ◽  
Straight Tubule ◽  
Glycerol Transport ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Urinary Concentrating Ability

The aquaporin-7 (AQP7) water channel is known as a member of the aquaglyceroporins, which facilitate the transport of glycerol as well as water. Although AQP7 is abundantly expressed on the apical membrane of the proximal straight tubules in the kidney, the physiological role of AQP7 is still unknown. To investigate this, we generated AQP7 knockout mice. The water permeability of the proximal tubule brush-border membrane measured by the stopped-flow method was slightly but significantly reduced in the AQP7 knockout mice compared with that of wild-type mice (AQP7, 18.0 ± 0.4 × 10−3 cm/s vs. wild-type, 20.0 ± 0.3 × 10−3 cm/s). Although AQP7 solo-knockout mice did not exhibit a urinary concentrating defect, AQP1/AQP7 double-knockout mice had a reduction in urinary concentrating ability compared with AQP1 solo-knockout mice, suggesting that the amount of water reabsorbed through AQP7 in the proximal straight tubules is physiologically substantial. On the other hand, AQP7 knockout mice showed marked glyceroluria (AQP7, 1.7 ± 0.34 mg/ml vs. wild-type, 0.005 ± 0.002 mg/ml). This identified a novel glycerol reabsorption pathway in the proximal straight tubules. In two mouse models of proximal straight tubule injury, the cisplatin-induced acute renal failure (ARF) model and the ischemic ARF model, an increase in urine glycerol was observed (pretreatment, 0.007 ± 0.005 mg/ml; cisplatin, 0.063 ± 0.043 mg/ml; ischemia, 0.076 ± 0.02 mg/ml), suggesting that urine glycerol could be used as a new biomarker for detecting proximal straight tubule injury.

Calcitonin selectively stimulates 25-hydroxyvitamin D3-1α-hydroxylase in proximal straight tubule of rat kidney

Nature ◽  
1981 ◽  
Vol 291 (5813) ◽  
pp. 327-329 ◽  
Author(s):  
Hiroyuki Kawashima ◽  
Shozo Torikai ◽  
Kiyoshi Kurokawa
Keyword(s):  
Rat Kidney ◽  
Straight Tubule ◽  
Proximal Straight Tubule

ANF inhibits norepinephrine-stimulated fluid absorption in rat proximal straight tubules

1992 ◽  
Vol 263 (4) ◽  
pp. F581-F585 ◽  
Author(s):  
J. L. Garvin
Keyword(s):  
Atrial Natriuretic Factor ◽  
Second Messenger ◽  
Ang Ii ◽  
Fluid Absorption ◽  
Straight Tubule ◽  
Cyclic Monophosphate ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Messenger System ◽  
Primary Interaction

We have previously shown that atrial natriuretic factor (ANF) only inhibits fluid absorption in the proximal straight tubule after the tissue has been exposed to angiotensin (ANG) II. In this paper, the interaction between ANF and norepinephrine (NE) in the proximal straight tubule was investigated. ANF alone (10(-9) M) added to the bath had no significant effect on fluid absorption. In contrast, when tubules were first treated with 10(-7) M NE, 10(-9) M ANF reduced fluid absorption from 0.63 +/- 0.09 to 0.41 +/- 0.04 nl.mm-1.min-1. NE alone stimulated fluid absorption by 33%. Dibutyryl-guanosine 3',5'-cyclic monophosphate (cGMP; 50 microM) mimicked the effects of ANF, reducing fluid absorption from 0.73 +/- 0.06 to 0.35 +/- 0.07 nl.mm-1.min-1 in NE-treated tubules. However, it had no effect on fluid absorption in the absence of NE. These studies suggest that 1) ANF can regulate fluid absorption in the proximal nephron; 2) this inhibition occurs only after transport has been stimulated by agents such as NE (or ANG II); 3) cGMP is part of the second messenger system of ANF in the rat proximal straight tubule; and 4) the primary interaction between ANF and NE (or ANG II) occurs in the second messenger cascades subsequent to steps that affect levels of cGMP.

Developmental expression of aquaporin 1 in the rat renal vasculature

1999 ◽  
Vol 276 (4) ◽  
pp. F498-F509 ◽  
Author(s):  
Jin Kim ◽  
Wan-Young Kim ◽  
Ki-Hwan Han ◽  
Mark A. Knepper ◽  
Søren Nielsen ◽  
...  
Keyword(s):  
Kidney Development ◽  
Rat Kidney ◽  
Water Channel ◽  
Developmental Expression ◽  
Renal Tubules ◽  
Renal Vasculature ◽  
Aquaporin 1 ◽  
Vasa Recta ◽  
Adult Kidney ◽  
Developing Rat

Aquaporin 1 (AQP-1) is a water channel protein that is constitutively expressed in renal proximal tubule and descending thin limb cells as well as in endothelial cells of the descending vasa recta. Studies in the developing rat kidney have demonstrated that AQP-1 is expressed in renal tubules before birth. However, nothing is known about the expression of AQP-1 in the renal vasculature during kidney development. The purpose of this study was to establish the distribution of AQP-1 in the renal vasculature of the developing rat kidney and follow the differentiation of the vascular system during kidney development. Kidneys from 16-, 17-, 18-, and 20-day-old fetuses and 1-, 4-, 7-, 14-, 21-, and 28-day-old pups were preserved and processed for immunohistochemical studies using a preembedding immunoperoxidase procedure. AQP-1 immunoreactivity was detected using affinity-purified rabbit polyclonal antibodies to AQP-1. AQP-1 was expressed throughout the arterial portion of the renal vasculature of the fetal and neonatal kidney from gestational age 17 days to 1 wk after birth. AQP-1 immunoreactivity gradually disappeared from the renal vasculature between 1 and 2 wk of age and remained only in the descending vasa recta. In contrast, AQP-1 immunoreactivity was not observed in lymphatic vessels until 3 wk of age and persisted in the adult kidney. AQP-1 was also expressed in a population of interstitial cells in the terminal part of the renal papilla at 3 wk of age as well as in the adult kidney. The transient expression of AQP-1 in the arterial portion of the renal vasculature in the developing rat kidney suggests that AQP-1 is important for fluid equilibrium and/or drainage in the developing kidney or, alternatively, plays a role in the regulation of growth and/or branching of the vascular tree during kidney development.

Expression of urea transporters in the developing rat kidney

2002 ◽  
Vol 282 (3) ◽  
pp. F530-F540 ◽  
Author(s):  
Young-Hee Kim ◽  
Dong-Un Kim ◽  
Ki-Hwan Han ◽  
Ju-Young Jung ◽  
Jeff M. Sands ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Rat Kidney ◽  
Outer Part ◽  
Vascular Bundles ◽  
Electron Microscopic ◽  
Outer Medulla ◽  
Intense Staining ◽  
Short Loop ◽  
Adult Kidney ◽  
Developing Rat

Urea transport in the kidney is mediated by a family of transporter proteins that includes renal urea transporters (UT-A) and erythrocyte urea transporters (UT-B). Because newborn rats are not capable of producing concentrated urine, we examined the time of expression and the distribution of UT-A and UT-B in the developing rat kidney by light and electron microscopic immunocytochemistry. Kidneys from 16-, 18-, and 20-day-old fetuses, 1-, 4-, 7-, 14-, and 21-day-old pups, and adult animals were studied. In the adult kidney, UT-A was expressed intensely in the inner medullary collecting duct (IMCD) and terminal portion of the short-loop descending thin limb (DTL) and weakly in long-loop DTL in the outer part of the inner medulla. UT-A immunoreactivity was not present in the fetal kidney but was observed in the IMCD and DTL in 1-day-old pups. The intensity of UT-A immunostaining in the IMCD gradually increased during postnatal development. In 4- and 7-day-old pups, UT-A immunoreactivity was present in the DTL at the border between the outer and inner medulla. In 14- and 21-day-old pups, strong UT-A immunostaining was observed in the terminal part of short-loop DTL in the outer medulla, and weak labeling remained in long-loop DTL descending into the outer part of the inner medulla. In the adult kidney, there was intense staining for UT-B in descending vasa recta (DVR) and weak labeling of glomeruli. In the developing kidney, UT-B was first observed in the DVR of a 20-day-old fetus. After birth there was a striking increase in the number of UT-B-positive DVR, in association with the formation of vascular bundles. The intensity of immunostaining remained strong in the outer medulla but gradually decreased in the inner medulla. We conclude that the expression of urea transporters in short-loop DTL and DVR coincides with the development of the ability to produce a concentrated urine.

Urinary acidification: CO2 transport by the rabbit proximal straight tubule

1977 ◽  
Vol 232 (1) ◽  
pp. F20-F25 ◽  
Author(s):  
D. G. Warnock ◽  
M. B. Burg
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Functional Heterogeneity ◽  
High Permeability ◽  
Straight Tubule ◽  
Urinary Acidification ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Tubule Fluid

Proximal straight tubules from rabbit kidneys were perfused in vitro in order to study transport of bicarbonate. Total CO2 content was measured in perfused and collected tubule fluid, using microcalorimetry. When the initial perfusate and bath contained 25 mM bicarbonate, the concentration of total CO2 decreased in the collected tubule fluid, indicating net reabsorption of bicarbonate. When the initial perfusate contained no bicarbonate and the bath contained 25 mM bicarbonate, total CO2 appeared in the collected tubule fluid. The rate at which total CO2 appeared in the tubule fluid was rapid, indicating a high permeability. Proximal straight tubules from superficial and juxtamedullary nephrons were compared and found to differ in permeability to CO2 and in transport rate. This functional heterogeneity may affect urinary acidification when there is redistribution of renal blood flow.

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