| Immunohistochemical localization of monoamine oxidase type B in pancreatic islets of the rat. | |
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MedLine Citation:
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PMID: 15923360 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Monoamine oxidase (MAO) is regarded as a mitochondrial enzyme. This enzyme localizes on the outer membrane of mitochondria. There are two kinds of MAO isozymes, MAO type A (MAOA) and type B (MAOB). Previous studies have shown that MAOB activity is found in the pancreatic islets. This activity in the islets is increased by the fasting-induced decrease of plasma glucose level. Islet B cells contain monoamines in their secretory granules. These monoamines inhibit the secretion of insulin from the B cells. MAOB is active in degrading monoamines. Therefore, MAOB may influence the insulin-secretory process by regulating the stores of monoamines in the B cells. However, it has not been determined whether MAOB is localized on B cells or other cell types of the islets. In the present study, we used both double-labeling immunofluorescence histochemical and electron microscopic immunohistochemical methods to examine the subcellular localization of MAOB in rat pancreatic islets. MAOB was found in the mitochondrial outer membranes of glucagon-secreting cells (A cells), insulin-secreting cells (B cells), and some pancreatic polypeptide (PP)-secreting cells (PP cells), but no MAOB was found in somatostatin-secreting cells (D cells), nor in certain other PP cells. There were two kinds of mitochondria in pancreatic islet B cells: one contains MAOB on their outer membranes, but a substantial proportion of them lack this enzyme. Our findings indicate that pancreatic islet B cells contain MAOB on their mitochondrial outer membranes, and this enzyme may be involved in the regulation of monoamine levels and insulin secretion in the B cells. |
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Authors:
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Yu-Hong Huang; Akio Ito; Ryohachi Arai |
Publication Detail:
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Type: Journal Article Date: 2005-05-27 |
Journal Detail:
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Title: The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society Volume: 53 ISSN: 0022-1554 ISO Abbreviation: J. Histochem. Cytochem. Publication Date: 2005 Sep |
Date Detail:
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Created Date: 2005-09-13 Completed Date: 2005-10-18 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9815334 Medline TA: J Histochem Cytochem Country: United States |
Other Details:
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Languages: eng Pagination: 1149-58 Citation Subset: IM |
Affiliation:
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Department of Anatomy, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Fluorescent Antibody Technique Immunohistochemistry Islets of Langerhans / cytology, enzymology*, ultrastructure Male Microscopy, Electron Monoamine Oxidase / metabolism* Rats Rats, Sprague-Dawley Subcellular Fractions / enzymology |
| Chemical | |
Reg. No./Substance:
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EC 1.4.3.4/Monoamine Oxidase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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