scholarly journals No major thermogenic role for (Na+ + K+)-dependent adenosine triphosphatase apparent in hepatocytes from hyperthyroid rats

1982 ◽  
Vol 202 (3) ◽  
pp. 661-665 ◽  
Author(s):  
D G Clark ◽  
M Brinkman ◽  
O H Filsell ◽  
S J Lewis ◽  
M N Berry
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Atpase Activity ◽  
Heat Production ◽  
Adenosine Triphosphatase ◽  
Heat Output ◽  
Liver Parenchymal ◽  
Dependent Atpase ◽  
Parenchymal Cells ◽  
Isolated Liver

(Na+ + K+)-dependent ATPase activity, heat production and oxygen consumption were increased by 59%, 62% and 75% respectively in hepatocytes from tri-iodothyronine-treated rats. Ouabain at concentrations of 1 and 10 mM decreased oxygen uptake by 2-8% in hepatocytes from euthyroid rats and by 5-15% in hepatocytes from hyperthyroid animals. Heat output was decreased by 4-9% with the glycoside in isolated liver parenchymal cells from the control animals and by 11% in the cells from the tri-iodothyronine-treated animals. These results do not support the hypothesis that hepatic (Na+ + K+)-ATPase plays a major role in increased heat production in hepatocytes from hyperthyroid rats.

Regulation of pyruvate kinase by 6-phosphogluconate in isolated hepatocytes

1981 ◽  
Vol 240 (3) ◽  
pp. E279-E285
Author(s):  
S. B. Smith ◽  
R. A. Freedland
Keyword(s):  
Pyruvate Kinase ◽  
Parenchymal Cell ◽  
Isolated Hepatocytes ◽  
Hill Coefficient ◽  
Liver Parenchymal Cell ◽  
Liver Parenchymal ◽  
Highly Correlated ◽  
Parenchymal Cells ◽  
The Hill ◽  
Isolated Liver

Isolated liver parenchymal cells from rats fed a 65% sucrose diet for 14 days were incubated in the presence and absence of 10(-6) M glucagon. The pyruvate kinase obtained from homogenates of the glucagon-treated cells displayed and increased Ks 0.5 for phosphoenolpyruvate (P-enolpyruvate), as well as an increased Ka 0.5 for 6-phosphogluconate (6-P-gluconate), compared to pyruvate kinase from untreated cells. Additionally, glucagon treatment decreased the maximal stimulation of pyruvate kinase by 6-P-gluconate by approximately two-thirds and decreased the Hill coefficient value of pyruvate kinase for 6-P-gluconate from 1.76 to 1.56. 6-Aminonicotinamide, an inhibitor of 6-P-gluconate dehydrogenase, increased 6-P-gluconate levels in isolated liver parenchymal cells three- to sevenfold, depending on the substrates present. The flux of P-enolpyruvate through pyruvate kinase was increased from 18 to 40% in these preparations and was highly correlated with the increase in 6-P-gluconate levels. The results suggest that 6-P-gluconate could regulate pyruvate kinase activity in the intact liver parenchymal cell. Furthermore, the activator would be of greatest importance in the lipogenic animal.

Renal oxygen consumption, thermogenesis, and amino acid utilization during i.v. infusion of amino acids in man

1994 ◽  
Vol 267 (5) ◽  
pp. E648-E655 ◽  
Author(s):  
T. Brundin ◽  
J. Wahren
Keyword(s):  
Amino Acids ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Amino Acid ◽  
Oxygen Uptake ◽  
Heat Production ◽  
Whole Body ◽  
Arterial Blood ◽  
Renal Oxygen Consumption ◽  
Renal Oxygen

The renal contribution to the amino acid-induced whole body thermogenesis was examined. Using indirect calorimetry and catheter techniques, pulmonary and renal oxygen uptake and blood flow, blood temperatures, and net renal exchange of amino acids, glucose and lactate were measured in eight healthy men before and during 3 h of intravenous infusion of 720 kJ of an amino acid solution. During the infusion, the pulmonary oxygen uptake increased from 252 +/- 12 to 310 +/- 8 ml/min, cardiac output increased from 5.9 +/- 0.3 to 6.8 +/- 0.3 l/min, and the arterial blood temperature increased from 36.34 +/- 0.04 to 36.68 +/- 0.07 degrees C. Renal oxygen consumption, heat production, blood flow, and net glucose exchange remained unchanged during the infusion. The net renal uptake of amino acid energy from the blood rose from 2 +/- 2 to 11 +/- 4 W. The total renal energy expenditure was 9-10 W throughout the study period. It is concluded that intravenous amino acid infusion greatly augments the uptake and utilization of amino acids in the kidneys but does not stimulate the renal oxygen consumption, heat production, blood flow, or glucose release.

HORMONE SENSITIVITY OF ISOLATED LIVER PARENCHYMAL CELLS

1974 ◽  
Vol 77 (1_Suppl) ◽  
pp. S98 ◽  
Author(s):  
H. Bojar ◽  
K. Balzer ◽  
M. Stannek ◽  
W. Reipen ◽  
W. Staib
Keyword(s):  
Liver Parenchymal ◽  
Hormone Sensitivity ◽  
Parenchymal Cells ◽  
Isolated Liver

Activity and energy expenditure in laying hens

1976 ◽  
Vol 86 (3) ◽  
pp. 471-473 ◽  
Author(s):  
M. Van Kampen
Keyword(s):  
Oxygen Consumption ◽  
Locomotor Activity ◽  
Body Temperature ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Heat Production ◽  
Energy Cost ◽  
Laying Hens ◽  
Different Types ◽  
Nesting Activity

SummaryThe energy cost of nesting activity and oviposition of hens in different environments has been determined.The oxygen consumption of hens on a wire floor reached a peak during the last 15 min before oviposition. However, the oxygen uptake of hens accustomed to a litter floor had fallen to a minimum at this time.The energy cost of expelling the egg is minimal. There is a good correlation between the locomotor activity and the heat production.The variations in heat production and body temperature on different types of floors are explicable by the differences in nesting activity.

The importance of the techniques employed during the enzymatic preparation of isolated liver parenchymal cells

1973 ◽  
Vol 82 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Douglas R. Labrecque ◽  
Nicholas R. Bachur ◽  
Janice A. Peterson ◽  
Roger B. Howard
Keyword(s):  
Enzymatic Preparation ◽  
Liver Parenchymal ◽  
Parenchymal Cells ◽  
Isolated Liver

PGE2 stimulates O2 uptake in hepatic parenchymal cells: involvement of the cAMP-dependent protein kinase

1999 ◽  
Vol 277 (5) ◽  
pp. G1048-G1054 ◽  
Author(s):  
Wei Qu ◽  
Lee M. Graves ◽  
Ronald G. Thurman
Keyword(s):  
Oxygen Consumption ◽  
Protein Kinase ◽  
Oxygen Uptake ◽  
Parenchymal Cell ◽  
Inhibitory Peptide ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Parenchymal Cells ◽  
Stimulation Of

The aim of this study was to determine which PGE2 receptors and signal transduction pathways are responsible for the stimulation of oxygen uptake in liver. Hepatic parenchymal cells isolated from female Sprague-Dawley rats were incubated either with PGE2, 17-phenyl-omega-trinor PGE2 (an EP1-specific agonist), or 11-deoxy PGE1 (an EP2/EP4-specific agonist), and oxygen consumption was measured. Both PGE2 and 11-deoxy PGE1 stimulated oxygen consumption. However, an EP1agonist was without effect. Although PGE2 elevated intracellular calcium, this occurred at concentrations ∼500-fold lower than that required to stimulate oxygen uptake. PGE2-stimulated increases in cAMP formation correlated well with the increase in oxygen consumption. Dibutyryl cAMP also increased oxygen consumption. Furthermore, N-[2-( p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide, a cell-permeable inhibitor of protein kinase A (PKA), reduced the stimulation of oxygen uptake by PGE2. Incubation of isolated parenchymal cell mitochondria with the purified catalytic subunit of PKA and ATP increased both state 3 rates of oxygen uptake and the respiratory control ratio by ∼50%. Activation of these events was prevented by incubation with the PKA inhibitory peptide, PKI. These findings are consistent with the hypothesis that PGE2 stimulates oxygen consumption via an EP2 and/or EP4 subclass of receptors through the actions of cAMP on a cAMP-dependent protein kinase.

Characteristics of lipoprotein receptors of the isolated liver parenchymal cells prepared from the streptozotocin-induced diabetic rats

Life Sciences ◽  
1986 ◽  
Vol 38 (7) ◽  
pp. 653-662 ◽  
Author(s):  
Tsuguhiko Nakai ◽  
Koji Oida ◽  
Toshitaka Tamai ◽  
Yasunori Kutsumi ◽  
Susumu Miyabo ◽  
...  
Keyword(s):  
Diabetic Rats ◽  
Lipoprotein Receptors ◽  
Liver Parenchymal ◽  
Parenchymal Cells ◽  
Isolated Liver
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