scholarly journals The effect of streptozotocin-induced diabetes on phenylalanine hydroxylase expression in rat liver

1989 ◽  
Vol 264 (1) ◽  
pp. 185-190 ◽  
Author(s):  
D S Taylor ◽  
H H M Dahl ◽  
J F B Mercer ◽  
A K Green ◽  
M J Fisher
Keyword(s):  
Gene Expression ◽  
Rat Liver ◽  
Phenylalanine Hydroxylase ◽  
Enzymic Activity ◽  
Hormonal Control ◽  
Significant Elevation ◽  
Translational Activity ◽  
Streptozotocin Induced Diabetes ◽  
The Impact ◽  
Specific Mrna

The impact of experimentally induced diabetes on the expression of rat liver phenylalanine hydroxylase has been investigated. A significant elevation in maximal enzymic activity was observed in diabetes. This was associated with significant increases in the amount of enzyme, the phenylalanine hydroxylase-specific translational activity of hepatic RNA and the abundance of phenylalanine hydroxylase-specific mRNA. These changes in phenylalanine hydroxylase expression were not observed when diabetes was controlled by daily injections of insulin. These results are discussed in relation to the hormonal control of phenylalanine hydroxylase gene expression.

scholarly journals The role of reversible phosphorylation in the hormonal control of phenylalanine hydroxylase in isolated rat proximal kidney tubules

1993 ◽  
Vol 292 (2) ◽  
pp. 419-424 ◽  
Author(s):  
S C B Richardson ◽  
R A Aspbury ◽  
M J Fisher
Keyword(s):  
Phenylalanine Hydroxylase ◽  
Enzymic Activity ◽  
Hormonal Control ◽  
Kidney Tubules ◽  
Reversible Phosphorylation ◽  
Proximal Tubule Cells ◽  
Major Mechanism ◽  
The Impact ◽  
First Time ◽  
Isolated Rat

Reversible phosphorylation is the major mechanism underlying the short-term hormonal control of phenylalanine hydroxylase activity in the liver. We report here, for the first time, the impact of a range of hormonal effectors on both the phosphorylation state and enzymic activity of phenylalanine hydroxylase present in isolated rat proximal kidney tubules. The most potent stimulator of enzyme phosphorylation was found to be parathyroid hormone, which is known to stimulate the production of cyclic AMP in proximal-tubule cells. In addition, adrenergic amines also stimulated enzyme phosphorylation, although to a lesser extent, through interaction with a mixed alpha 1 and beta receptor population.

Comparison of Different Methods for the Determination of Phenylalanine Hydroxylase Activity in Rat Liver and Euglena gracilis

1984 ◽  
Vol 39 (7-8) ◽  
pp. 728-733 ◽  
Author(s):  
Rita M. Fink ◽  
Erich F. Elstner
Keyword(s):  
Rat Liver ◽  
Euglena Gracilis ◽  
Phenylalanine Hydroxylase ◽  
Hplc Method ◽  
Enzymic Activity ◽  
Hydroxylase Activity ◽  
Product Separation ◽  
Tyrosine Concentration ◽  
Layer Chromatography

Abstract Three different methods for the determination of phenylalanine hydroxylase activity have been compared: a) Differential photometric assay of the increase in tyrosine concentration in the presence of phenylalanine; b) Product separation by thin layer chromatography and scintillation counting of the [14C]tyrosine formed;c) HPLC separation and spectrofluorometric quantification of derivatized amino acids. A comparison of the activities of phenylalanine hydroxylase in rat liver and Euglena gracilis clearly showed that only rat liver contains this enzymic activity as shown by methods b) and c) although pseudo-activity of Euglena gracilis preparations was found during the spectrophotometric test a). The HPLC method proved to be the fastest, most reliable and convenient method for direct tyrosine determination and thus for measuring phenylalanine hydroxylase activity.

Regulation of rat Na+/Pi cotransporter-1 gene expression: the roles of glucose and insulin

1996 ◽  
Vol 271 (6) ◽  
pp. E1021-E1028 ◽  
Author(s):  
H. Li ◽  
P. Ren ◽  
M. Onwochei ◽  
R. J. Ruch ◽  
Z. Xie
Keyword(s):  
Gene Expression ◽  
Glucose Metabolism ◽  
Primary Culture ◽  
Rat Liver ◽  
Inorganic Phosphate ◽  
Rat Hepatocytes ◽  
Cdna Clones ◽  
Homeostatic Regulation ◽  
Liver And Kidney ◽  
Streptozotocin Induced Diabetes

Cytosolic inorganic phosphate (P(i)) is important for glucose metabolism. It plays a role in homeostatic regulation of glucose by insulin and glucagon. Recently, we isolated two cDNA clones for rat Na+/P(i) cotransporter-1 (rNaPi-1) and demonstrated that they are expressed primarily in the rat liver and kidney. We now report that the expression of rNaPi-1 in these tissues is regulated by fasting and streptozotocin-induced diabetes. Using rat hepatocytes in primary culture, we also demonstrate that glucose and insulin upregulate rNaPi-1 expression, whereas glucagon and elevated intracellular adenosine 3',5'-cyclic monophosphate levels downregulate its expression. Because 2-deoxyglucose exhibits no effect on rNaPi-1 gene expression, we suggest that some metabolite accumulated during glucose metabolism may be responsible for the effects of glucose and insulin on rNaPi-1 gene expression. Our data also reveal that other known Na+/P(i) cotransporter genes, NaPi-2 and Ram-1 (a receptor for amphotropic murine retrovirus), are not regulated by insulin and glucose. It is therefore proposed that various subtypes of Na+/P(i) cotransporters are differentially regulated and that each subtype may be involved in a specific cellular function, rNaPi-1 may be responsible for Pi uptake by liver and kidney for glucose metabolism, whereas NaPi-2 may play a key role in P(i) reabsorption in the kidney.

Hormonal control of specific gene expression in the rat liver during the suckling-weaning transition

1990 ◽  
Vol 30 ◽  
pp. 91-108 ◽  
Author(s):  
Dominique Perdereau ◽  
Michael Narkewicz ◽  
Christine Coupe ◽  
Pascal Ferre ◽  
Jean Girard
Keyword(s):  
Gene Expression ◽  
Rat Liver ◽  
Hormonal Control ◽  
Specific Gene ◽  
Specific Gene Expression

scholarly journals Impacts of Macronutrients on Gene Expression: Recent Evidence to Understand Productive and Reproductive Performance of Livestock

2018 ◽  
Vol 6 (2) ◽  
pp. 203 ◽  
Author(s):  
Md. Mahmodul Hasan Sohel ◽  
Yusuf Konca ◽  
Mehmet Ulas Cinar
Keyword(s):  
Gene Expression ◽  
Reproductive Performance ◽  
Quantitative Measurement ◽  
Molecular Level ◽  
Specific Gene ◽  
Qpcr Array ◽  
Use Of Knowledge ◽  
The Impact ◽  
Generation Sequencing ◽  
Specific Mrna

In order to identify the effects of nutrients on gene expression and to assess the interactions between genes and nutrition by means of various cutting-edge technologies, the interdisciplinary branch ‘Nutrigenomics’ was created. Therefore, nutrigenomics corresponds to the use of knowledge and techniques of nutrition, genomics, transcriptomics, proteomics, epigenomics, and metabolomics to seek and explain the cross-talk between nutrition and genes in molecular level. Macronutrients are important dietary signals that control metabolic programming of cells and have important roles in maintaining cellular homeostasis by influencing specific gene expression. Recent advancements in molecular genetics studies, for instance, use of next-generation sequencing, microarray and qPCR array to investigate the expression of transcripts, genes, and miRNAs, has a crucial impact on understanding and quantitative measurement of the impact of dietary macronutrients on gene function. This review will shade a light on the interactions and mechanisms how the dietary source of macronutrients changes the expression of specific mRNA and miRNA. Furthermore, it will highlight the exciting recent findings in relation to animal performance characteristics which eventually help us to identify a dietary target to improve animal production.

scholarly journals The isolation and properties of phenylalanine hydroxylase from rat liver

1974 ◽  
Vol 139 (3) ◽  
pp. 731-739 ◽  
Author(s):  
Shirley Su Gillam ◽  
Savio L. C. Woo ◽  
Louis I. Woolf
Keyword(s):  
Rat Liver ◽  
Phenylalanine Hydroxylase ◽  
Protein Band ◽  
Enzymic Activity ◽  
Hydroxylation Reaction ◽  
Single Protein ◽  
Thiol Binding ◽  
Filtration Step ◽  
Preliminary Filtration ◽  
Haem Iron

Phenylalanine hydroxylase was prepared from rat liver and purified 200-fold to about 90% purity. All the enzymic activity of the liver appeared in a single protein of mol.wt. approx. 110000, but omission of dithiothreitol and of a preliminary filtration step to remove lipids resulted in partial conversion into a second enzymically active protein of mol.wt. approx. 250000. The Km and Vmax. values of the enzyme for phenylalanine, p-fluorophenylalanine and dimethyltetrahydropterin were measured; p-chlorophenylalanine inhibited the enzyme by competing with phenylalanine. Disc gel electrophoresis at pH7.2 showed a single protein band containing all the enzymic activity, but at pH8.7 the enzyme dissociated into two inactive fragments of similar but not identical molecular weight. The molecule of phenylalanine hydroxylase contained two atoms of iron, one atom of copper and one molecule of FAD; molybdenum was absent. Treatment with chelating agents showed that both non-haem iron and copper were necessary for enzymic activity. The molecule contained five thiol groups, and thiol-binding reagents inhibited the enzyme. Catalase or peroxidase enhanced enzymic activity fivefold; it is postulated that catalase (or other peroxidase) plays a part in the hydroxylation reaction independent of the protection by catalase of enzyme and cofactor from inactivation by a hydroperoxide.

Streptozotocin-induced diabetes affects in rat liver citrate carrier gene expression by transcriptional and posttranscriptional mechanisms

2011 ◽  
Vol 43 (11) ◽  
pp. 1621-1629 ◽  
Author(s):  
Fabrizio Damiano ◽  
Elisa Mercuri ◽  
Eleonora Stanca ◽  
Gabriele Vincenzo Gnoni ◽  
Luisa Siculella
Keyword(s):  
Gene Expression ◽  
Rat Liver ◽  
Streptozotocin Induced Diabetes ◽  
Citrate Carrier
Sign in / Sign up

Export Citation Format

Share Document