Role of Fatty Acids in Simultaneous Regulation of Flux Through Glutaminase and Glutamine Synthetase in Rat Kidney Cortex

1984 ◽  
pp. 187-202 ◽  
Author(s):  
G. Baverel ◽  
C. Michoudet ◽  
G. Martin
Keyword(s):  
Fatty Acids ◽  
Glutamine Synthetase ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex

scholarly journals PPARα Gene Expression in the Developing Rat Kidney: Role of Glucocorticoids

2001 ◽  
Vol 12 (6) ◽  
pp. 1197-1203
Author(s):  
FATIMA DJOUADI ◽  
JEAN BASTIN
Keyword(s):  
Gene Expression ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Culture Media ◽  
Rat Kidney ◽  
Fold Increase ◽  
Kidney Cortex ◽  
Peroxisome Proliferator ◽  
Rat Kidney Cortex

Abstract. The α isoform of peroxisome proliferator-activated receptor (PPARα), which is highly expressed in the kidney, can stimulate the expression of genes that are involved in fatty acid catabolism and therefore might be involved in the control of renal fatty acid β-oxidation. PPARα expression and its regulation in the immature kidney are not well documented. This study delineated the developmental pattern of PPARα expression in the rat kidney cortex and the medulla between postnatal days 10 and 30 and investigated the role of glucocorticoids in regulating PPARα expression. In the cortex, PPARα mRNA and protein increased 2- and 1.8-fold, respectively, from 10 to 21 d and then decreased 1.5- and 2.4-fold from 21 to 30 d. In the medulla, PPARα mRNA and protein increased continuously 3.3- and 2.4-fold, respectively. It is shown here that acute treatment by dexamethasone of 10-d-old rats precociously induced a 4- to 6-fold increase in PPARα mRNA and a 1.8-fold increase in protein within 6 h in each part of the kidney. Chronic injection of dexamethasone for 3 d also increased PPARα mRNA 3.8- and 2.2-fold in the cortex and the medulla, respectively, with a 1.5- and 2-fold increase in protein. Furthermore, adrenalectomy prevented the increases in PPARα mRNA and protein in both the cortex and the medulla between postnatal days 16 and 21, and these could be restored by dexamethasone treatment. Finally, with the use of an established renal cell line, it was shown that glucocorticoids stimulate gene expression of PPARα and of medium chain acyl-CoA dehydrogenase (MCAD, a PPARα target gene) 2- to 4-fold and 1.5-fold, respectively, and that addition of fatty acids in the culture media led to a 2.2-fold increase in MCAD mRNA. Altogether, these results demonstrated that glucocorticoids are potent regulators of PPARα development in the immature kidney and that these hormones act in concert with fatty acids to regulate MCAD gene expression in renal cells.

Cytochrome P-450K of rat kidney cortex microsomes: Further studies on its interaction with fatty acids

1973 ◽  
Vol 158 (2) ◽  
pp. 597-604 ◽  
Author(s):  
Åke Ellin ◽  
Sten Orrenius ◽  
Åke Pilotti ◽  
Carl-Gunnar Swahn
Keyword(s):  
Fatty Acids ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex

Inhibitory Role of Ca2+ in the Control of Renin Secretion: A Study Using Supervised Dispersed Rat Renal Cortical Cells

1989 ◽  
Vol 77 (3) ◽  
pp. 273-279 ◽  
Author(s):  
Karen Pardy ◽  
B. C. Williams ◽  
A. R. Noble
Keyword(s):  
Rat Kidney ◽  
Renin Secretion ◽  
Renin Release ◽  
Kidney Cortex ◽  
Cortical Cells ◽  
Rat Kidney Cortex ◽  
Cyclic Monophosphate ◽  
Cortex Cell ◽  
The Mean

1. The role of Ca2+ in the control of renin release was investigated using a collagenase-dispersed rat kidney cortex cell preparation. 2. Superfusion with a series of low [Ca2+] buffers in either ascending or descending order of concentration increased renin release. Exposure to 0.06 mmol/l Ca2+ increased release by 120% (P < 0.001) when presented as the first buffer in ascending order of concentration and by 79% (P < 0.001) when presented as the fourth and last in a series of descending order. 3. The Ca2+ entry blocking drug diltiazem in a range of concentrations increased renin release and at 10−5 mol/l diltiazem the mean stimulation was 35% (P < 0.01). 4. 8-(N,N-Diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) reduces the release of Ca2+ from intracellular stores and, studied over a range of concentrations, this compound increased renin release. At 10−5 mol/l TMB-8 the mean increase was 44% (P < 0.001). 5. None of these experimental manipulations, low [Ca2+], diltiazem or TMB-8, had any effect on the release of adenosine 3′:5′-cyclic monophosphate into the cell superfusate, indicating that a decrease in intracellular [Ca2+] increases renin release by a mechanism which is independent of changes in adenosine 3′:5′-cyclic monophosphate production. 6. Effects of low [Ca2+], diltiazem and TMB-8 on renin secretion were all shown to be reversible when superfusion with control buffer was resumed.

Effect of bicarbonate on glutamine and glutamate metabolism by rat kidney cortex mitochondria

1985 ◽  
Vol 249 (4) ◽  
pp. F573-F581
Author(s):  
R. C. Scaduto ◽  
A. C. Schoolwerth
Keyword(s):  
Rat Kidney ◽  
Competitive Inhibitor ◽  
Kidney Cortex ◽  
Mitochondrial Enzymes ◽  
Glutamate Metabolism ◽  
Bicarbonate Buffer ◽  
Rat Kidney Cortex ◽  
Glutamate Oxalacetate Transaminase ◽  
Stimulation Of

Isolated rat kidney cortex mitochondria were incubated at pH 7.4 in the presence or absence of a CO2/bicarbonate buffer (28 mM) to investigate the pH-independent role of bicarbonate on glutamine and glutamate metabolism. Changes in the concentration of key intermediates and products during the incubations were used to calculate metabolite flux rates through specific mitochondrial enzymes. With 1 mM glutamine and 2 mM glutamate as substrates, bicarbonate caused an inhibition of glutamate oxalacetate transaminase flux and a stimulation of glutamate deamination. The same effects were also produced with addition of either aminooxyacetate or malonate. These effects of bicarbonate were prevented when 0.2 mM malate was included as an additional substrate. Bicarbonate ion was identified as a potent competitive inhibitor of rat kidney cortex succinate dehydrogenase. These results indicate that aminooxyacetate, malonate, and bicarbonate all act to stimulate glutamate deamination through a suppression of glutamate transamination, and that the control by transamination of glutamate deamination is due to alterations in alpha-ketoglutarate metabolism. In contrast, in mitochondria incubated with glutamine in the absence of glutamate, bicarbonate was found to inhibit glutamate dehydrogenase flux. This effect was found to be due in part to the lower intramitochondrial pH observed in incubations with bicarbonate. These findings indicate that bicarbonate ion, independent of pH, may have an important regulatory role in renal glutamine and glutamate metabolism.

Presence and possible role of a renal brush-border Gly-Pro-X-releasing exopeptidase

1987 ◽  
Vol 253 (4) ◽  
pp. F649-F655
Author(s):  
Knut-Jan Andersen ◽  
J. Ken McDonald
Keyword(s):  
Brush Border ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Membrane Domains ◽  
Rat Kidney Cortex ◽  
Proximal Tubule Cells ◽  
Dpp Iv ◽  
Tripeptidyl Peptidase ◽  
Membrane Compartment

Differential pelleting of a rat renal cortical homogenate clearly demonstrated the microsomal localization of an N-terminal exopeptidase of the tripeptidyl peptidase (TPP) class that typically requires a free N-terminus to catalyze the release of collagen-related (Gly-Pro-X) “triplets” at pH 7.0 (TPP 7). Once fractionated by differential pelleting, microsomal populations of different size were subfractionated by equilibrium banding in sucrose gradients for the purpose of comparing the distribution profiles and the isopycnic banding densities of TPP 7 to those for known marker enzymes. This analytical approach permitted the localization of these enzymes to specific membrane domains in the renal cortex and provided evidence for the brush-border location of TPP 7. Notably, dipeptidyl peptidase IV (DPP IV), an established plasma membrane exopeptidase with a prolyl-bond specificity, gave banding densities and distributions that were consistent with the presence of both TPP 7 and DPP IV in the same membrane compartment. Because triplets of the Gly-Pro-X type released by TPP 7 would be ideal substrates for DPP IV, a coupled TPP 7-DPP IV exopeptidase mechanism at the luminal surface (brush border) of proximal tubule cells could therefore make a major contribution to the renal degradation and reabsorption of filtered collagen fragments. tripeptidyl peptidase; aminopeptidase; collagen; rat kidney cortex Submitted on February 11, 1987 Accepted on May 13, 1987

scholarly journals Na+-gradient-dependent stimulation of renal transport of ρ-aminohippurate

1982 ◽  
Vol 208 (1) ◽  
pp. 243-246 ◽  
Author(s):  
M I Sheikh ◽  
J V Møller
Keyword(s):  
Rat Kidney ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Cortex Slices ◽  
Kidney Cortex Slices ◽  
Stimulation Of

Transport of rho-aminohippurate was studied by the use of a preparation of rabbit kidney basolateral-membrane vesicles and in rat kidney-cortex slices under anaerobic conditions. With both preparations clear evidence of Na+-gradient stimulation of rho-aminohippurate transport (‘overshoot’) was obtained. These results thus indicate that a significant aspect of active rho-aminohippurate transport is by co-transport with Na+, and they appear to resolve previous disagreements concerning the role of Na+. Vesicle studies with a potential-sensitive dye suggested that rho-aminohippurate may be transported electroneutrally, i.e. in a 1:1 complex with Na+.

Sign in / Sign up

Export Citation Format

Share Document