scholarly journals Species and tissue distribution of the regulatory protein of glucokinase

1993 ◽  
Vol 294 (2) ◽  
pp. 551-556 ◽  
Author(s):  
A Vandercammen ◽  
E Van Schaftingen
Keyword(s):  
Guinea Pig ◽  
Rat Liver ◽  
Human Liver ◽  
Regulatory Protein ◽  
Control Level ◽  
Streptozotocin Diabetes ◽  
Diabetic Rats ◽  
Rat Tissues ◽  
Adult Rat ◽  
Toad Bufo

Rat liver is known to contain a regulatory protein that inhibits glucokinase (hexokinase IV or D) competitively versus glucose. This inhibition is greatly reinforced by the presence of fructose 6-phosphate and antagonized by fructose 1-phosphate and by KCl. This protein was now measured in various rat tissues and in the livers of various species by the inhibition it exerts on rat liver glucokinase. Rat, mouse, rabbit, guinea-pig and pig liver, all of which contain glucokinase, also contained between 60 and 200 units/g of tissue of a regulatory protein displaying the properties mentioned above. By contrast, this protein could not be detected in cat, goat, chicken or trout liver, or in rat brain, heart, skeletal muscle, kidney and spleen, all tissues from which glucokinase is missing. Fructose 1-phosphate stimulated glucokinase in extracts of human liver, indicating the presence of regulatory protein. In addition, antibodies raised against rat regulatory protein allowed the detection of an approximately 60 kDa polypeptide in rat, guinea pig, rabbit and human liver. The livers of the toad Bufo marinus, of Xenopus laevis and of the turtle Pseudemys scripta elegans contained a regulatory protein similar to that of the rat, with, however, the major difference that it was not sensitive to fructose 6-phosphate or fructose 1-phosphate. In rat liver, the regulatory protein was detectable 4 days before birth. Its concentration increased afterwards to reach the adult level at day 30 of extrauterine life, whereas glucokinase only appeared after day 15. In the liver of the adult rat, starvation and streptozotocin-diabetes caused a 50-60% decrease in the concentration of regulatory protein after 7 days, whereas glucokinase activity fell to about 20% of its initial level. When 4-day-starved rats were refed, or when diabetic rats were treated with insulin, the concentration of regulatory protein slowly increased to reach about 85% of the control level after 3 days, whereas the glucokinase activity was normalized after the same delay. The fact that there appears to be no situation in which glucokinase is expressed without regulatory protein is in agreement with the notion that the regulatory protein forms a functional entity with this enzyme.

scholarly journals A study of the localization of polynucleotide phosphorylase within rat liver cells and of its distribution among rat tissues and diverse animal species

1972 ◽  
Vol 130 (2) ◽  
pp. 355-362 ◽  
Author(s):  
Y P See ◽  
P. S. Fitt
Keyword(s):  
Guinea Pig ◽  
Rat Liver ◽  
Rat Heart ◽  
Animal Species ◽  
Physiological Role ◽  
Rat Tissues ◽  
Mitochondrial Enzyme ◽  
Polynucleotide Phosphorylase ◽  
Rat Liver Cells ◽  
Kidney Liver

1. Rat liver polynucleotide phosphorylase was localized in the mitochondrion, but may also occur in the nucleus. 2. The mitochondrial enzyme was found in rat heart, kidney, liver, muscle and spleen. 3. Mitochondrial polynucleotide phosphorylase is also present in calf, chicken, guinea-pig and rabbit liver and in goldfish muscle. 4. A possible physiological role for the enzyme in the control of the intramitochondrial ADP concentration is suggested.

scholarly journals Effect of streptozotocin-diabetes on rat liver mitochondrial adenosine triphosphatase turnover

1988 ◽  
Vol 251 (2) ◽  
pp. 621-624 ◽  
Author(s):  
A Jordá ◽  
E Pérez-Pastor ◽  
M Portolés
Keyword(s):  
Rat Liver ◽  
Half Life ◽  
Adenosine Triphosphatase ◽  
Streptozotocin Diabetes ◽  
Diabetic Rats ◽  
Mitochondrial Enzymes ◽  
Turnover Rates ◽  
Membrane Atpase ◽  
Isotope Technique ◽  
Double Isotope

The apparent turnover rates of some mitochondrial enzymes can be modified in diabetes. We studied the effect of streptozotocin-diabetes on the half-life of a protein tightly bound to the inner membrane, ATPase. The half-life (t 1/2), measured by the double-isotope technique, decreased by approx. 20% in diabetes (from approximately equal to 2.56 days in controls to approximately equal to 2.06 days in diabetic rats). These results suggest that diabetes produces an increase in degradation of ATPase by a mechanism which is not yet clear, possibly influenced by alterations induced by diabetes in hepatic lysosomes that are associated with hepatic autophagy.

scholarly journals DHRS3, a retinal reductase, is differentially regulated by retinoic acid and lipopolysaccharide-induced inflammation in THP-1 cells and rat liver

2012 ◽  
Vol 303 (5) ◽  
pp. G578-G588 ◽  
Author(s):  
Reza Zolfaghari ◽  
Qiuyan Chen ◽  
A. Catharine Ross
Keyword(s):  
Retinoic Acid ◽  
Mrna Expression ◽  
Rat Liver ◽  
Reductase Activity ◽  
In Vitro Transcription ◽  
Whole Body ◽  
Rat Tissues ◽  
Gene Target ◽  
Adult Rat

Both retinoid status and inflammation have been shown to control the level of expression of retinoid homeostatic genes. In the present study, DHRS3, previously shown to possess retinal reductase activity, was identified by microarray analysis of THP-1 monocytes as a possible gene target of all- trans-retinoic acid (RA). In these cells, DHRS3 mRNA increased 30- to 40-fold after treatment with ≤20 nM RA for 24 h, while DHRS3 protein also increased. Of several synthetic retinoids tested, only Am580, a RA receptor-α-selective retinoid, increased DHRS3 mRNA expression. The full-length DHRS3 cDNA was cloned from rat liver and subjected to in vitro transcription-translation. Two major ∼30- and 35-kDa proteins were detected. In adult rat tissues, DHRS3 mRNA was most abundant in the adrenal gland, liver, and ovary. In the liver, DHRS3 is expressed in hepatocytes and possibly in all liver cells. To evaluate whether DHRS3 is regulated in the liver by RA and/or inflammatory stimuli, we treated rats for 6 h with RA or LPS or both. DHRS3 mRNA was doubled by RA but reduced by >90% after treatment with LPS in the absence and presence of RA. On the basis of our results, DHRS3 mRNA expression is regulated by RA in a tissue- or cell-type specific manner; the RA-induced increase in DHRS3 may contribute to retinoid storage; and a reduction of DHRS3 expression in the liver during inflammation may contribute to the perturbation of whole body vitamin A metabolism that has previously been shown to occur in conditions of inflammatory stress.

scholarly journals Formation and utilization of 3-hydroxy-3-methylglutarate in liver mitochondria of starved and streptozotocin-diabetic rats

1978 ◽  
Vol 172 (3) ◽  
pp. 371-375 ◽  
Author(s):  
R Deana ◽  
M Fabbro ◽  
F Rigoni
Keyword(s):  
Guinea Pig ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Diabetic Rats ◽  
Rat Liver Mitochondria ◽  
Streptozotocin Diabetic Rats ◽  
Coa Hydrolase

Kidney and liver mitochondria of rat, rabbit and guinea pig are able to transform 3-hydroxy-3-methylglutarate into acetoacetate, whereas ox liver mitochondria and rat mitochondria of heart, diaphragm and brain do not exhibit such an activity. Starvation and streptozotocin treatment decreases the formation of acetoacetate from 3-hydroxy-3-methylglutarate. Addition of acetoacetate and succinate to the incubation media of mitochondria results in a decrease in the transformation of 3-hydroxy-3-methylglutarate into acetoacetate. A 3-hydroxy-3-methylglutaryl-CoA hydrolase is present in rat liver mitochondria; the activity does not show appreciable changes after starvation or streptozotocin treatment.

scholarly journals G-protein-mediated regulation of the insulin-responsive glucose transporter in isolated cardiac myocytes

1990 ◽  
Vol 272 (3) ◽  
pp. 691-696 ◽  
Author(s):  
J Eckel ◽  
E Gerlach-Eskuchen ◽  
H Reinauer
Keyword(s):  
Cyclic Amp ◽  
Cholera Toxin ◽  
G Protein ◽  
Pertussis Toxin ◽  
Glucose Transporter ◽  
Streptozotocin Diabetes ◽  
Diabetic Rats ◽  
Stimulatory Action ◽  
Adult Rat ◽  
Protein Functions

Isolated muscle cells from adult rat heart were used to study the involvement of G-proteins in the regulation of the glucose transporter by insulin and isoprenaline. Efficient modification of G-protein functions was established by measuring isoprenaline-stimulated cyclic AMP production, viability and ATP content after treating the cells with cholera toxin and pertussis toxin for 2 h. Under these conditions cholera toxin decreased the stimulatory action of insulin on 3-O-methylglucose transport by 56%, but pertussis toxin had no effect. Basal transport was not affected by toxin treatment. Isoprenaline increased 3-O-methylglucose transport by 63%. This effect was not mimicked by dibutyryl cyclic AMP, but was completely blocked by cholera toxin. Streptozotocin-diabetes abolished isoprenaline action and decreased stimulation of transport by 64%. Concomitantly, cholera-toxin sensitivity of glucose transport was lost in cells from diabetic animals. This was paralleled by a large decrease (87 +/- 4%) in mRNA expression of the insulin-regulatable glucose transporter, as shown by Northern-blot analysis of RNA isolated from cardiomyocytes of diabetic rats. These data suggest a functional association between the insulin-responsive glucose transporter and a cholera-toxin-sensitive G-protein mediating stimulation by insulin and isoprenaline.

Comparison of Thy–1 expression in human liver cirrhosis and different models of rat liver injury

2006 ◽  
Vol 44 (01) ◽  
Author(s):  
T Mansuroglu ◽  
J Dudas ◽  
B Saile ◽  
D Batusic ◽  
G Ramadori
Keyword(s):  
Liver Cirrhosis ◽  
Liver Injury ◽  
Rat Liver ◽  
Human Liver ◽  
Human Liver Cirrhosis

Hepatic uptake of intact glutathione S-conjugate, inhibition by organic anions, and sinusoidal catabolism

1993 ◽  
Vol 265 (3) ◽  
pp. G547-G554
Author(s):  
C. A. Hinchman ◽  
A. T. Truong ◽  
N. Ballatori
Keyword(s):  
Guinea Pig ◽  
Rat Liver ◽  
Marked Decrease ◽  
Hepatic Uptake ◽  
Half Time ◽  
High Concentrations ◽  
Rat Livers ◽  
Dose Dependent ◽  
Uptake And Metabolism ◽  
Guinea Pig Liver

To identify potential mechanisms for hepatic removal of circulating glutathione (GSH) conjugates, uptake and metabolism of S-2,4-dinitrophenylglutathione (DNP-SG) were examined in isolated perfused livers from rat and guinea pig. Guinea pig livers perfused with 5 mumol of DNP-SG in a recirculating system (50 microM initial concn) rapidly cleared the conjugate from the perfusate (half time 3.7 min), whereas clearance was considerably slower in rat liver (half time 35 min). Disappearance of DNP-SG from the perfusate was accompanied by a simultaneous appearance of DNP-SG and its metabolites in bile. Addition of acivicin, an inhibitor of gamma-glutamyltransferase (gamma-GT), to the perfusate resulted in a marked decrease in DNP-SG clearance by guinea pig liver but had no effect in rat liver, suggesting that in the guinea pig this process is largely dependent on sinusoidal gamma-GT activity. However, even in the presence of acivicin, rat and guinea pig livers removed nearly one-half of the administered DNP-SG from the recirculating perfusate over 30 min. High concentrations of DNP-SG were found in bile (up to 3.7 mM), indicating that the liver is capable of transporting the intact conjugate from the circulation. When rat livers were perfused with higher concentrations of DNP-SG (100 and 250 microM), biliary excretion of DNP-SG increased dose dependently, with concentrations in bile reaching 10 mM at the higher dose. This was accompanied by a dose-dependent choleresis.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Induction of amino acid transport in primary cultures of adult rat liver parenchymal cells by insulin.

1976 ◽  
Vol 251 (10) ◽  
pp. 3014-3020 ◽  
Author(s):  
R F Kletzien ◽  
M W Pariza ◽  
J E Becker ◽  
V R Potter ◽  
F R Butcher
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Amino Acid Transport ◽  
Primary Cultures ◽  
Acid Transport ◽  
Liver Parenchymal ◽  
Adult Rat ◽  
Parenchymal Cells

scholarly journals Aldehyde dehydrogenase in 2-acetaminofluorene-induced rat hepatomas. Ontogeny and evidence that the new isoenzymes are not due to normal gene de-repression

1977 ◽  
Vol 164 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Ronald Lindahl
Keyword(s):  
Rat Liver ◽  
Aldehyde Dehydrogenase ◽  
Double Diffusion ◽  
Normal Liver ◽  
Normal Adult ◽  
Sprague Dawley ◽  
Adult Liver ◽  
Aldehyde Dehydrogenases ◽  
Adult Rat ◽  
Liver Aldehyde Dehydrogenase

The pre- and post-natal ontogeny of Sprague–Dawley rat liver aldehyde dehydrogenase [aldehyde–NAD(P)+ oxidoreductase, EC 1.2.1.5] is described. At no time in its ontogenetic development does normal liver aldehyde dehydrogenase exhibit any of the characteristics of a series of unique aldehyde dehydrogenases that can be isolated from 2-acetamidofluorene-induced rat hepatomas. Enzyme activity is first detectable in 15-day foetal liver and gradually increases throughout pre- and post-natal development until adult activities are attained by day 49 after birth. Electrophoretically, normal aldehyde dehydrogenase, throughout its ontogeny, exists as the same single isoenzyme found in normal adult liver. Isoelectric points for two normal liver isoenzymes demonstrable by isoelectric focusing are pH5.9 and 6.0. The immunochemical properties of aldehyde dehydrogenase during its ontogeny are identical with those of normal adult liver aldehyde dehydrogenase when tested against anti-(hepatoma aldehyde dehydrogenase) serum in Ouchterlony double-diffusion tests. The results indicate that the hepatoma-specific aldehyde dehydrogenases are not the result of the de-repression of genes normally repressed in adult rat liver or in some other adult tissue.

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