Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.99.1 (NADPH-diaphorase)
3,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Growth hormone (GH), thyroxine (T4) and insulin were injected, in utero into 20.5 day-old rat fetuses to study the effects of these hormones on the activities of liver NADPH dehydrogenase, glucose-6-phosphatase and glycogen phosphorylase. It was found that at 21.5 days of gestation, GH increases the fetal liver glucose-6-phosphatase activity and decreases the liver glycogen phosphorylase activity. T4 treatment augments the activity of NADPH dehydrogenase even at 0.3% of the dose shown previously to produce premature elevation of activity. Prior to this experiment T4 in large doses has been shown to be capable of elevating glucose-6-phosphatase. However, at the lower T4 dose used, no treatment effect was observed. The fetal rat liver is responsive to insulin at 21.5 days and insulin was able to depress glucose-6-phosphatase activity. Thereby, showing that the influence of insulin on this enzyme begins prior to birth instead of just subsequent to birth.
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PMID:The effects of growth hormone, thyroxine and insulin on the activities of reduced nicotinamide adenine dinucleotide phosphate dehydrogenase, glucose-6-phosphatase and glycogen phosphorylase in fetal rat liver. 22 53

NG-Nitro-L-arginine, an inhibitor of nitric oxide (NO) synthase, markedly (+50%) increased the L-arginine-induced insulin release from isolated mouse islets but did not itself influence insulin secretion. An abundance of mouse islet cells were positively stained for the enzyme NADPH diaphorase, which reportedly is a marker for NO synthase. The data suggest that the NO synthase activity in mouse islet tissue may inhibit insulin secreting processes and that L-arginine has a dual action on insulin release.
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PMID:Inhibition of islet nitric oxide synthase increases arginine-induced insulin release. 128 75

A film test for the rapid detection of plasma/serum 3-hydroxybutyrate (3-OHB) has been developed. The film contains NAD, nitro blue tetrazolium, 3-OHB dehydrogenase, and diaphorase, and the surface is coated with modified biomembrane and can detect 50-1500 microM 3-OHB within 2-3 min. One drop or 50 microliters of plasma/serum or blood is applied to the film, and the violet color is read via reflectance meter after 2 min. Plasma/serum samples greater than 1500 microM 3-OHB can be measured by dilution with saline. In blood with 40% hematocrit, the color developed is 50% less than with plasma/serum, and this was adjusted in the reflectance meter. A good correlation (r = 0.99) was observed between results with automated and film methods and between visual methods and reflectance meter. In insulin-dependent diabetes mellitus, all 3 subjects with positive ketonuria (+ +), 8 of 12 subjects with mild ketonuria (+), and 7 of 25 subjects without ketonuria exhibited elevation of 3-OHB in blood greater than 200 microM. The results indicate that 3-OHB film is valuable not only in the emergency room for the differential diagnosis between ketoacidotic and nonketotic hypersomolar coma but also as a marker for insulin dependency, energy dependency on fatty acid compared with glucose, and metabolic control of diabetes.
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PMID:Development of stable film test for rapid estimation of blood or plasma 3-hydroxybutyrate. 235 Oct 30

NADPH-diaphorase activity, which has been previously reported to be associated with the enzyme nitric oxide synthase (NOS), was localized cytochemically in the pancreatic islets of normal rats. All islet cells types, i.e. insulin-, glucagon-, somatostatin- and pancreatic polypeptide-immunoreactive cells, expressed NAD-PH-diaphorase histochemical activity, whereas the exocrine tissue was almost negative. In streptozotocin-treated rats, only the surviving non-beta cells in the islet periphery were stained. Isolated beta and non-beta cells also expressed intense NADPH-diaphorase activity. By electron microscopy, the enzyme was localized primarily on membranes of the endoplasmic reticulum and nuclear envelope, as previously reported for neurons. In addition the enzyme activity was found in the cis-region of the Golgi complex. These results suggest that the four types of endocrine cells of the islets of Langerhans may contain the NOS-enzyme and thus constitutively produce nitric oxide.
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PMID:Cytochemical localization of NADPH-diaphorase in the four types of pancreatic islet cell. 752 33

Nitric oxide has recently been implicated as a cellular molecule that mediates interleukin-1 beta (IL-1 beta)-induced inhibition of glucose-stimulated insulin secretion by islets of Langerhans. In this study evidence is presented which demonstrates that islets contain both the cytokine inducible and the constitutive isoforms of nitric oxide synthase as determined by NADPH diaphorase staining and immunohistochemical localization. Untreated islets contain NADPH diaphorase activity, and the intensity of NADPH diaphorase staining is dramatically increased after culture for 18 hrs with IL-1 beta. Both control and IL-1 beta-induced NADPH diaphorase staining of islets is inhibited by the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (NMMA). Importantly, approximately 60-70% of islet cells stained positive for NADPH diaphorase (under both IL-1 beta treated and control conditions), suggesting that a subset of islet cells contain nitric oxide synthase. The beta-cell appears to be the endocrine cell type which contains constitutive nitric oxide synthase as demonstrated by immunohistochemical co-localization of constitutive nitric oxide synthase and insulin. IL-1 beta is believed to stimulate the expression of cytokine inducible nitric oxide synthase because the synthetic glucocorticoid, dexamethasone, prevents IL-1 beta induced inhibition of glucose stimulated insulin secretion and cGMP accumulation by islets. Both dexamethasone, and the nitric oxide synthase inhibitors NMMA and aminoguanidine also prevent IL-1 beta induced islet degeneration. These results indicate that nitric oxide produced by the inducible isoform of nitric oxide synthase mediates cytokine induced islet dysfunction and destruction, and that the beta-cell is the islet endocrine cellular source of constitutive nitric oxide synthase.
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PMID:Nitric oxide mediates IL-1 beta-induced islet dysfunction and destruction: prevention by dexamethasone. 769 96

Glutamate and related molecules are the major excitatory neurotransmitters in the central nervous system, and their receptors have been localized therein. Little is, however, known about them in the peripheral nervous system. The present study investigated the localization of glutamate receptor subunits of the alpha-amino-3-hydroxy- 5-methyl-4-isoxazolepropionate (AMPA) type (GluR1, GluR2-3, and GluR4) in the pancreas of newborn guinea pigs. With a double-labeling method of immunofluorescence and immuno-tetrahydrochloride reaction, GluR1 and GluR4 immunoreactivities were localized mostly in the insulin-secreting cells in the central mass of the islet, and GluR2-3 immunoreactivity in the peripheral rim of the islet, which consists mainly of non-insulin-secreting islet cells. With a double-labeling method employing immunofluorescence and NADPH-diaphorase (NADPH-d) histochemistry, GluR2-3 and GluR4 immunoreactivities were localized in most of the NADPH-d positive pancreatic ganglion cells. None of the NADPH-d-positive ganglion cells showed GluR1 immunoreactivity. In fact, GluR1 immunoreactivity was not detected in any of the pancreatic ganglion cells. The results indicate that glutamate is likely to exert its effects on the pancreas by activating different AMPA receptor subunits located in endocrine cells and intrapancreatic ganglia.
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PMID:Localization of glutamate receptor subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type in the pancreas of newborn guinea pigs. 916 82

The principal goal of the present study was to test the hypothesis that cytokines modulate glucose transport in skeletal muscle by increasing nitric oxide production. Cultured L6 skeletal muscle cells were incubated in the presence of tumour necrosis factor-alpha, interferon-gamma or lipopolysaccharide (LPS) alone or in combination for 24 h. Neither cytokines nor LPS alone induced NO production, as measured by nitrite concentrations in the medium. However, when used in combination, the two cytokines significantly stimulated NO production, and this effect was synergistically enhanced by the presence of LPS. Reverse transcriptase-PCR (RT-PCR) analysis revealed that NO release was associated with the induction of inducible (macrophage-type) NO synthase (iNOS). The increase in iNOS expression was confirmed at the protein level by Western-blot analysis and NADPH/diaphorase histochemical staining. Cytokines and LPS markedly increased basal glucose transport in L6 myocytes. Insulin also stimulated basal glucose transport, but significantly less in cells chronically exposed to cytokines/LPS. The sensitivity of L6 muscle cells to insulin-stimulated glucose transport was also significantly decreased by cytokines/LPS treatment. The NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME) inhibited nitrite production in cytokine/LPS-treated cells, and this prevented the increase in basal glucose transport and restored muscle cell responsiveness to insulin. Cytokines/LPS exposure significantly increased GLUT1 transporter protein levels but decreased GLUT4 expression in L6 cells. l-NAME treatment prevented the increase in GLUT1 protein content but failed to restore GLUT4 transporter levels. These results demonstrate that cytokines and LPS affect glucose transport and insulin action by inducing iNOS expression and NO production in skeletal muscle cells. The data further indicate that cytokines and LPS increase the expression of the GLUT1 transporter protein by an NO-dependent mechanism.
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PMID:Cytokines modulate glucose transport in skeletal muscle by inducing the expression of inducible nitric oxide synthase. 923 Jan 32

Previous studies have shown that nitric oxide synthase (NOS), the enzyme that catalyzes the formation of nitric oxide (NO), is expressed in skeletal muscle. The aim of the present study was to test the hypothesis that NO can modulate glucose metabolism in slow- and fast-twitch skeletal muscles. Calcium-dependent NOS was detected in skeletal muscle, and the enzyme activity was greater in fast-type extensor digitorum longus (EDL) muscles than in slow-type soleus muscles. Both the neuronal-type (nNOS) and endothelial-type (eNOS) enzymes are expressed in resting skeletal muscles. However, nNOS protein was only detected in EDL muscles, whereas eNOS protein contents were comparable in soleus and EDL muscles. NOS expression in muscle cryosections (diaphorase histochemistry) was located in vascular endothelium and in muscle fibers, and the staining was greater in type IIb than in type I and IIa fibers. The macrophage-type inducible NOS (iNOS) was not detected in resting muscle, but endotoxin treatment induced its expression, concomitant with elevated NO production. iNOS induction was associated with impaired insulin-stimulated glucose uptake in isolated rat muscles. In vitro, NOS blockade with specific inhibitors did not affect basal or insulin-stimulated glucose transport in EDL or soleus muscles. In contrast, the NO donors GEA 5024 and sodium nitroprusside induced dose-dependent inhibition (up to 50%) of maximal insulin-stimulated glucose transport in both muscles with minor effects on basal uptake values. GEA 5024 also blunted insulin-stimulated glucose transport and amino acid uptake in cultured L6 muscle cells without affecting insulin binding to its receptor. On the other hand, the permeable cGMP analogue dibutyryl cGMP did not affect muscle glucose transport. These results strongly suggest that NO modulates insulin action in both slow- and fast-type skeletal muscles. This novel autocrine action of NO in muscle appears to be mediated by cGMP-independent pathways.
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PMID:Expression of nitric oxide synthase in skeletal muscle: a novel role for nitric oxide as a modulator of insulin action. 935 14

To evaluate the role of nitric oxide synthase (nNOS) in the pathogenesis of diabetic neuropathy, we investigated nociception and nNOS expression in dorsal root ganglion (DRG) of rats with streptozocin-induced diabetes. Paw withdrawal threshold to noxious mechanical stimuli was decreased in both L-NAME-treated and diabetic rats. The number of NADPH-diaphorase positive neurons was significantly decreased in untreated diabetic compared with control rats. Decreased expression of nNOS protein was confirmed by immunoblotting. Insulin treatment completely prevented decreases in withdrawal threshold and nNOS expression. Cyclic GMP content paralleled nNOS expression in experimental animals. These results suggest that decreased nNOS-cGMP system in DRG may play a role in the pathogenesis of diabetic sensory neuropathy.
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PMID:Hyperalgesia and decreased neuronal nitric oxide synthase in diabetic rats. 950 63

Plasma arginine vasopressin (AVP) is known to be elevated in patients with uncontrolled insulin-dependent diabetes mellitus who have plasma hyperosmolality with hyperglycaemia. Although osmotic stimuli cause an increase in nitric oxide synthase (NOS) activity as well as synthesis of AVP and oxytocin in the paraventricular (PVN) and supraoptic nuclei (SON), it is not known whether NOS activity in the hypothalamus changes in the diabetic patients who have plasma hyperosmolality with hyperglycaemia caused by insulin deficiency. Expression of the neuronal (n) NOS gene in the PVN and SON in streptozotocin (STZ)-induced diabetic rats was investigated by using in situ hybridization histochemistry and NADPH-diaphorase histochemical staining. Four weeks after intraperitoneal (i. p.) administration of STZ, male Wistar rats developed hyperglycaemia and plasma hyperosmolality. The expression of nNOS gene and NADPH-diaphorase staining in the PVN and SON remarkably increased in STZ-induced diabetic rats compared to control rats. Three weeks after administration of STZ, the diabetic rats were subcutaneously treated with insulin for 1 week, which resulted in significant suppression of the induction of nNOS, AVP and oxytocin gene expression in the PVN and SON. Furthermore, the induction of nNOS gene expression in the PVN and SON was suppressed in STZ-induced diabetic rats treated with phlorizin and diet to normalize hyperglycaemia without insulin treatment. These results suggest that upregulation of nNOS gene expression as well as AVP and oxytocin gene expression in the PVN and SON in STZ-induced diabetic rats may be associated with hyperglycaemia and plamsa hyperosmolality.
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PMID:Upregulation of hypothalamic nitric oxide synthase gene expression in streptozotocin-induced diabetic rats. 966 44


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