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:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. A morphological and physiological comparison was made between embryonically and postnatally derived superior cervical ganglion neurons (SCGN) grown in dissociated cell culture. It was found that while morphologically distinct, the physiological properties of the postnatal neurons were the same as their embryonic counterparts. 2. Intracellular injection of horseradish peroxidase (HPR) demonstrated that SCGN from any age of animal elaborated two basic types of processes, although the pattern of process ramification was unique for each neuron. The two types of proceses were 1) the large, smooth, rapidly tapering; and 2) the thin, nontapering variety, which often contained varicosities along its length. It is suggested that the former are dendritic in function, while the latter act as axons. 3. A difference was noted in somal size and the number of primary processes extended by the embryonic and postnatal neurons, with the latter more closely resembling the in vivo morphology. 4. Resting potentials and action-potential amplitudes of postnatal SCGN were comparable to those found previously for embryonic SCGN in vitro. 5. Iontophoretic application of putative neurotransmitter substances revealed the presence of acetylcholine receptors (AChR) on both embryonic and postnatal SCGN. Picrotoxin-sensitive depolarizing responses to iontophoresed gamma-aminobutyric acid (GABA) was seen on a few embryonic neurons, but not on the older cells. No responses were detected when norepinephrine (NE), glutamate, cAMP, substance P, or dopamine were applied to the SCGN of either age group. 6. Synatpic interaction between postnatal SCGN were found at an earlier in vitro age (12 days) than was the case for embryonic neurons (20 days). 7. Synaptic transmission was found to be chemical in nature. This was shown by 1) a dependence on external Ca2+ concentrations; 2) steplike fluctuations in synpatic potential amplitude, and 3) a variation in potential amplitude with changes in membrane potential. 8. It is concluded that the postnatal SCGN are able to survive in culture even when taken from animals up to 12.5 wk old. The elaboration of processes is in many ways strikingly similar to sympathetic neurons in the animal, and they are able to form functional synaptic interactions.
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PMID:Postnatal rat sympathetic neurons in culture. I. A comparison with embryonic neurons. 3 83

Rats, pretreated with thyroxine for 2 days, were given one or two iv injections of 500 mU of TSH; in some groups the second TSH dose was replaced by 0.75 micronmol isoproternol. The effects of the thyroid stimulators on the following parameters were studied: the number of exocytotic vesicles in the follicle cells; the incorporation of 125I into thyroid proteins, measured over periods of 5 min; and the thyroidal cAMP contents. At 2 h after TSH administration, a second dose of TSH failed to stimulate iodination while at 8 h the iodination response was "normal". Two hours after TSH the follicle cells contained practically no exocytotic vesicles but at 8 h they had a full supply of vesicles, and this was emptied by the second TSH injection. THE CAMP content was less increased by the second TSH injection than by the first one, but the stimulatory effect of the second TSH dose on cAMP was the same at 2 h and at 8 h; this indicates that the lack of iodination response at 2 h was not simply due to blocking of TSH receptors. Isoproternol, which acts on other receptors than does TSH, cause a similar cAMP increase incontrols and at 2 h and 8 h after TSH, but stimulated iodination only in controls and at 8 h after TSH; this supported the conclusion that the lack of iodination response to a second TSH dose at 2 h was not due to impairment of the adenylate cyclase-cAMP system. These observations taken together strongly indicate that a rapid iodination response to TSH depends on stimulated exocytosis which, in turn, requires a pool of exocytotic vesicles in the follicle cells. Such a coupling between exocytosis and iodination seems appropriate since by exocytosis uniodinated thyroglobulin and membrane, showing peroxidase activity histochemically, are delivered to the site of iodination, the apical cell surface.
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PMID:Effects of thyrotropin on thyroglobulin exocytosis and iodination in the rat thyroid gland. 21 93

Guanosine 3',5'-cyclic monophosphate (cGMP) immunoreactivity in the rat's cerebellum was studied with light and electron microscopy by the indirect fluorescence method and the peroxidase-antiperoxidase method. Labeled cells included neuroglial cells in the cerebellar cortex, white matter, and deep nuclei; some stellate and basket cells in the cortex; and some large neurons in the deep nuclei. No evidence was found for sagittal microzonation in the cGMP distribution. In the labeled cells, cGMP immunoreactive sites were localized to surface membranes, organelles, and the cytoplasmic matrix. Specificity was indicated by the same pattern of labeling after treatment with cGMP immunoglobulin that had been adsorbed with adenosine 3',5'-cyclic monophosphate (cAMP) and by the failure to label after treatment with normal rabbit sera or with cGMP immunoglobulin that had been adsorbed with 1 mM cGMP. Cerebella treated with cAMP antisera, however, showed immunoreactivity in Purkinje cells, granule cells, and Golgi cells in addition to neuroglia in cortex and deep nuclei. Sequential norepinephrine and glutamate superfusions generally intensified cGMP immunoreactivity, not only in neuroglial cells but also in the background. Under these conditions some Purkinje cells and some granule cells were also labeled. Increased cGMP immunoreactivity was also obtained by treatment with harmaline, gamma-aminobutyric acid and aminooxyacetic acid, muscimol, gamma-aminobutyric acid, or apomorphine in order of decreasing effectiveness. Serotonin and colchicine produced no detectable increase of cGMP immunoreactivity above normal, and diazepam and sodium pentobarbital decreased it. In these experiments, diethyl ether was preferable to sodium pentobarbital for anesthesia on account of the depressive action of the latter on cGMP immunoreactivity. Thus, drugs that increase cerebellar activity enhance cGMP levels, whereas those that decrease cerebellar activity decrease cGMP levels. However, it is not clear whether these fluctuations in cGMP levels are a direct consequence of neurotransmitter function or are sequelae to other related events. The present study suggests that some neurons and many neuroglial cells are the major sites of cGMP in the cerebellum.
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PMID:Immunocytochemical localization of cyclic GMP: light and electron microscope evidence for involvement of neuroglia. 22 Jun 17

Responses of blood platelets to bacterial endotoxin lipopolysaccharide (LPS) have been correlated with changes in the molecular organization and composition of the platelet plasma membrane proteins. Binding of LPS, which occurred in the absence of Ca2+, was distinguished from platelet aggregation and degranulation, which required Ca2+ and plasma proteins. Changes in membrane organization were detected by double-labelling with [125I] and [131I] iodide, mediated by lactoperoxidase and hydrogen peroxide. Changes in total membrane composition were detected by gel electrophoresis of isolated membranes. Binding of LPS was associated with increased accessibility of a protein of mol. wt. 80000 to iodination. After aggregation and degranulation there was, in addition, increased accessibility of proteins of mol. wt. 68000 and 48000. Isolated membranes from LPS-stimulated platelets contained more of a protein of mol. wt. 200000 and less of a protein of mol. wt. 220000 than control membranes prepared from unstimulated platelets in the presence of cAMP and aminophylline. The relationship of the modified plasma membrane proteins to the contractile proteins of the platelet and their possible redistribution in the cell during aggregation and secretion is discussed.
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PMID:Endotoxin-induced platelet aggregation and secretion. II. Changes in plasma membrane proteins. 59 72

Two specific methods, Northern blot analysis using a 50 nucleotides probe to the conserved region of the nerve growth factor (NGF) gene, and enzyme immunoassay using a monoclonal biotinylated rat anti-NGF IgG-avidin conjugated peroxidase system, were used to demonstrate the production and secretion of NGF by mouse striated muscle cell line G8-1. Calcium ionophore, A23187 (0.1-1 microM), forskolin (0.1-100 microM) and dibutyryl cyclic AMP (0.1-10 mM) strongly decreased the secretion of ir-NGF. The level of NGF mRNA was decreased by veratridine, A23187, forskolin and cyclic AMP but not by cyclic GMP. Consequently, we conclude that the secretion of NGF molecules paralleled the changes of NGF mRNA levels in the cells induced by all agents tested. Carmamylcholine also decreased the level of NGF mRNA. Immunoblot analysis suggested that denatured ir-NGF molecules exist in a higher molecular weight form (22 KDa) than those of mouse submaxillary gland (13 KDa). Both Ca(2+)- and cAMP mediated mechanisms contribute to the decreased production of NGF mRNA in the cells and the consequent inhibition of secretion of NGF molecules. Finally, molecular cloning of NGF of G8-1 cells was conducted and confirmed the structure of the gene that consists of 1, 3, and 4 exons deleting exon 2. Thus, G8-1 NGF is derived from transcript B.
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PMID:Production and secretion of nerve growth factor by clonal striated muscle cell line, G8-1. 128 21

We have evaluated two novel enzyme-linked immunosorbent assays (ELISAs) used to quantitate cyclic AMP. In one assay ELISA plates are coated with antigen consisting of a cyclic AMP-polylysine conjugate. Cyclic AMP samples added to plates are quantified by their ability to decrease the binding and anti-cyclic AMP antibodies to the coated antigen. A second ELISA utilizes a plated anti-immunoglobin technique in which plates are coated first with anti-goat IgG and then with goat anti-cyclic AMP antiserum. Cyclic AMP samples are quantified by their ability to compete with cyclic AMP-peroxidase conjugates for binding to the plated anti-cyclic AMP antibodies. The plated anti-immunoglobin ELISA proved to be somewhat more sensitive than the plated antigen ELISA and was comparable in sensitivity to an automated RIA for measuring cyclic AMP in standards and urine samples. Our data fit with the generalization that optimal ELISA sensitivity is obtained through the use of plated anti-immunoglobins rather than plated antigens. Further they demonstrate the practicality of utilizing small ligand-enzyme conjugates for ELISAs.
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PMID:Solid phase enzyme immunoassay of cyclic adenosine 3',5'-monophosphate. Effect of coating strategy upon assay performance in comparison with radioimmunoassay. 132 Dec

Simple, rapid and sensitive competitive enzyme immunoassays for the estimation of adenosine 3',5' cyclic monophosphate (cAMP) and guanosine 3',5' cyclic monophosphate (cGMP) in human plasma and urine are described. Specific antisera to each nucleotide were raised in rabbits by immunization with succinyl cyclic nucleotide--human serum albumin conjugates. For the assay, specific antibodies were incubated with a mixture of succinyl cyclic nucleotide labelled with horseradish peroxidase together with unlabelled standard or sample. The antibody-bound enzyme conjugate was separated from free hapten by anti-rabbit (IgG) sera immobilized to a microtitre plate. Activity of the bound enzyme conjugate was determined with tetramethylbenzidine. The assays were capable of detecting levels as low as 2 fmol of cAMP and cGMP. Good correlations were obtained between values generated by enzyme immunoassay and radioimmunoassay.
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PMID:Enzyme immunoassays for the estimation of adenosine 3',5' cyclic monophosphate and guanosine 3',5' cyclic monophosphate in biological fluids. 132 96

When HL-60 cells were stimulated with histamine, a significant differentiation of the cells toward neutrophils was elicited. Histamine increased phagocytic activity, but it reduced myeloperoxidase activity of HL-60 cells. Histamine-induced differentiation in HL-60 cells was inhibited not only by H2 antagonists, such as cimetidine, ranitidine and famotidine, but also by an inhibitor of protein kinase A (A kinase), KT-5720. Histamine increased the cAMP level and A kinase activity in HL-60 cells; both increases preceded the cell differentiation. Histamine also enhanced phosphorylation of a 160 kD protein in HL-60 cells, while H2 antagonists and KT-5720 inhibited this phosphorylation. The results of the present study indicate that an activation of A kinase via H2 receptor stimulation may cause the phosphorylation of a 160 kD protein and that this phosphorylation is probably involved in the process leading to differentiation of HL-60 cells.
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PMID:Histamine-induced differentiation of HL-60 cells. The role of cAMP and protein kinase A. 132 60

The occurrence of serotonin in the human adrenal gland was demonstrated both by immuno-histochemical and biochemical approaches. Using specific polyclonal antibodies to serotonin, the presence of numerous immunoreactive cells was revealed by means of the peroxidase-antiperoxidase technique. These cells exhibited the morphological characteristics of mast cells. Combination of high performance liquid chromatography and electrochemical detection showed the presence of substantial amounts of both serotonin and its metabolite 5-hydroxyindolacetic acid in adrenocortical extracts. The role of serotonin in the regulation of steroidogenesis from human adrenocortical slices was studied in vitro using a perifusion system technique coupled to a specific radioimmunoassay for cortisol. Graded doses of serotonin (from 10(-8) M to 3 x 10(-7) M) increased cortisol production in a dose-dependent manner. Prolonged exposure of adrenal fragments to serotonin (10(-7) M) induced a biphasic response, i.e. a rapid and transient increase in cortisol secretion followed by a plateau phase, suggesting the existence of a desensitization phenomenon. The stimulatory effect of serotonin (10(-7) M) was not altered during infusion of the serotonin1 and/or serotonin2 receptor antagonists methysergide (10(-6) M) and ketanserin (10(-6) M), respectively. In contrast, ICS 205 930 (10(-6) M), a non-selective serotonin3/serotonin4 antagonist, totally abolished the response of adrenal slices to serotonin (10(-7) M). The benzamide derivative zacopride, considered as a serotonin4 agonist, induced a robust stimulation of cortisol secretion. In addition, the corticotropic effects of serotonin (10(-7) M) and zacopride (10(-6) M) were not additive. Incubation of adrenocortical fragments with zacopride (10(-6) M) or serotonin (10(-6) M) caused a significant increase in cAMP formation. Taken together, these data suggest that serotonin, locally released by intra-adrenal mast-like cells, may act as a paracrine factor to stimulate cortisol secretion in man. Our results also indicate that serotonin-induced corticosteroid production is mediated through activation of a serotonin4 receptor subtype positively coupled to adenylate cyclase.
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PMID:Serotonin-induced stimulation of cortisol secretion from human adrenocortical tissue is mediated through activation of a serotonin4 receptor subtype. 137 44

Endocytosis in the chloride secreting epithelial cell line T84 was monitored by uptake of the fluid-phase markers FITC-dextran and horseradish peroxidase (HRP). Uptake of marker was inhibited by incubation of cells at 4 degrees C, consistent with an endocytic uptake. Although activation of the cAMP-dependent second messenger pathway has been shown to stimulate exocytosis in this cell line, it caused a 63% reduction in endocytosis as measured by uptake of fluid-phase markers. In contrast, the presence of the protein kinase C activator phorbol-myristate acetate (PMA) caused no significant reduction in the level of endocytosis compared to control, nor did it reverse the inhibitory effect of PKA activation. The data thus suggest that endocytosis in T84 cells is regulated through activation of protein kinase A, but not through activation of protein kinase C.
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PMID:Endocytosis is regulated by protein kinase A, but not protein kinase C in a secretory epithelial cell line. 137 55


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