scholarly journals DIRECT COUNTING AND SIZING OF MITOCHONDRIA IN SOLUTION

1972 ◽  
Vol 54 (2) ◽  
pp. 325-345 ◽  
Author(s):  
Adrian R. L. Gear ◽  
Jana M. Bednarek
Keyword(s):  
Electron Microscopy ◽  
Rat Liver ◽  
Rat Kidney ◽  
Mitochondrial Protein ◽  
Kidney Cortex ◽  
Rat Liver Mitochondria ◽  
Particle Volume ◽  
Drug Induced ◽  
Rat Kidney Cortex ◽  
The Mean

Resistive particle counting has been developed for the accurate sizing and counting of mitochondria in solution. The normal detection limit with a 30 µ aperture is 0.48 µ diameter, or 0.056 µ3 particle volume The mean volume of rat liver mitochondria was 0.42 µ3 or 0.93 µ in diameter. The average value for numbers of particles per milligram of mitochondrial protein was 4.3 x 103, and per gram of rat liver was about 11 x 1010. These values compare satisfactorily with those derived by light microscopy and electron microscopy. The mean volume for mitochondria from rat heart was 0 60 µ3 and from rat kidney cortex, 0.23 µ3. These values agree within 15% of those determined by electron microscopy of whole tissue. Mitochondrial fragility and contaminating subcellular organelles were shown to have little influence on the experimentally determined size distributions The technique may be applied to rapid swelling studies, as well as to estimations of the number and size of mitochondria from animals under different conditions such as liver regeneration and hormonal, pathological, or drug-induced states Mitochondrial DNA, RNA, cytochrome c-oxidase, cytochrome (a ÷ a3), and iron were nearly constant per particle over large differences in particle size. Such data may be particularly valuable for biogenesis studies and support the hypothesis that the net amount per particle of certain mitochondrial constituents remains constant during mitochondrial growth and enlargement

Studies on the metabolism of glycolyl-CoA

1990 ◽  
Vol 68 (5) ◽  
pp. 846-851 ◽  
Author(s):  
Joseph Vamecq ◽  
Jacques H. Poupaert
Keyword(s):  
Rat Liver ◽  
Pyruvate Dehydrogenase ◽  
Citrate Synthase ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Liver Mitochondria ◽  
Succinic Semialdehyde ◽  
Succinic Semialdehyde Dehydrogenase ◽  
Rat Kidney Cortex ◽  
Semialdehyde Dehydrogenase

Glycolyl-CoA can be formed during the course of the β-oxidation by rat liver mitochondria of 4-hydroxybutyrate. The existence of this β-oxidation has been previously supported by the occurrence of 4-hydroxybutyrate and its β-oxidation catabolites in urine from patients with 4-hydroxybutyric aciduria, an inborn error of γ-aminobutyric acid metabolism due to the deficiency of succinic semialdehyde dehydrogenase. The characteristics of the mitochondrial β-oxidation of 4-hydroxybutyrate were, in rat liver, compared with those of the mitochondrial β-oxidation of butyrate. The inhibition by malonate of the oxidation of 4-hydroxybutyrate was about twofold weaker than that of oxidation of butyrate, whereas both oxidations were abolished by preincubating the mitochondria with 1 mM valproic acid, a known inhibitor of mitochondrial β-oxidation. Mitochondria from rat kidney cortex were demonstrated to catalyse, as previously shown for hepatic mitochondria, the carnitine-dependent oxidation of 12-hydroxylauroyl-CoA. ω-Hydroxymonocarboxylyl-CoAs are thus concluded to be precursors of glycolyl-CoA also in rat kidney cortex. In addition, 3-hydroxypyruvate was found to be a precursor of glycolyl-CoA, since it was oxidized by bovine heart pyruvate dehydrogenase with a cofactor requirement similar to that of pyruvate oxidation. Glycolyl-CoA was a substrate of carnitine acetyltransferase (pigeon breast muscle). Pig heart citrate synthase was capable of catalyzing the condensation of glycolyl-CoA with oxaloacetate. The product of this reaction induced low NADH production rates dependent on the addition of porcine heart aconitase and isocitrate dehydrogenase.Key words: glycolyl-CoA, ω-hydroxymonocarboxylates, β-oxidation, 4-hydroxybutyrate, CoA-dependent 3-hydroxypyruvate oxidation, pyruvate dehydrogenase, citrate synthase, hydroxy citrate.

scholarly journals Carbohydrate metabolism of the perfused rat liver

1967 ◽  
Vol 105 (2) ◽  
pp. 869-875 ◽  
Author(s):  
B. D. Ross ◽  
R. Hems ◽  
R. A. Freedland ◽  
H. A. Krebs
Keyword(s):  
Rat Liver ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Additive Effects ◽  
Perfusion Medium ◽  
Rat Kidney Cortex ◽  
Low Carbohydrate Diet ◽  
Low Carbohydrate ◽  
Glycogen Stores ◽  
Glucose Formation

1. The rates of gluconeogenesis from most substrates tested in the perfused livers of well-fed rats were about half of those obtained in the livers of starved rats. There was no difference for glycerol. 2. A diet low in carbohydrate increased the rates of gluconeogenesis from some substrates but not from all. In general the effects of a low-carbohydrate diet on rat liver are less marked than those on rat kidney cortex. 3. Glycogen was deposited in the livers of starved rats when the perfusion medium contained about 10mm-glucose. The shedding of glucose from the glycogen stores by the well-fed liver was greatly diminished by 10mm-glucose and stopped by 13·3mm-glucose. Livers of well-fed rats that were depleted of their glycogen stores by treatment with phlorrhizin and glucagon synthesized glycogen from glucose. 4. When two gluconeogenic substrates were added to the perfusion medium additive effects occurred only when glycerol was one of the substrates. Lactate and glycerol gave more than additive effects owing to an increased rate of glucose formation from glycerol. 5. Pyruvate also accelerated the conversion of glycerol into glucose, and the accelerating effect of lactate can be attributed to a rapid formation of pyruvate from lactate. 6. Butyrate and oleate at 2mm, which alone are not gluconeogenic, increased the rate of gluconeogenesis from lactate. 7. The acceleration of gluconeogenesis from lactate by glucagon was also found when gluconeogenesis from lactate was stimulated by butyrate and oleate. This finding is not compatible with the view that the primary action of glucagon in promoting gluconeogenesis is an acceleration of lipolysis. 8. The rate of gluconeogenesis from pyruvate at 10mm was only 70% of that at 5mm. This ‘inhibition’ was abolished by oleate or glucagon.

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.

scholarly journals Increase of Na/Pi-cotransport encoding mRNA in response to low Pi diet in rat kidney cortex.

1994 ◽  
Vol 269 (9) ◽  
pp. 6637-6639
Author(s):  
A. Werner ◽  
S.A. Kempson ◽  
J. Biber ◽  
H. Murer
Keyword(s):  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex

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

scholarly journals Studies on the orientation of brush-border membrane vesicles

1978 ◽  
Vol 172 (1) ◽  
pp. 57-62 ◽  
Author(s):  
W Haase ◽  
A Schäfer ◽  
H Murer ◽  
R Kinne
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Rat Kidney ◽  
Freeze Fracture ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Immunological Methods ◽  
Kidney Cortex ◽  
Asymmetric Distribution ◽  
Rat Kidney Cortex

Orientation of rat renal and intestinal brush-border membrane vesicles was studied with two independent methods: electron-microscopic freeze-fracture technique and immunological methods. With the freeze-fracture technique a distinct asymmetric distribution of particles on the two membrane fracture faces was demonstrated; this was used as a criterion for orientation of the isolated membrane vesicles. For the immunological approach the accessibility or inaccessibility of aminopeptidase M localized on the outer surface of the cell membrane to antibodies was used. With both methods we showed that the brush-border membrane vesicles isolated from rat kidney cortex and from rat small intestine for transport studies are predominantly orientated right-side out.

Endogenous Kallikrein Inhibitor in Rat Kidney Cortex-Effect of Glucocorticoid Administration

1986 ◽  
pp. 361-365 ◽  
Author(s):  
Kodo Ito ◽  
Kenichi Yamada ◽  
Setsuko Yoshida ◽  
Keiji Hasunuma ◽  
Yasushi Tamura ◽  
...  
Keyword(s):  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Kallikrein Inhibitor ◽  
Glucocorticoid Administration
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