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  • 1990-1994  (3)
  • 1945-1949
  • nitric oxide  (2)
  • Diphenoxyphosphorylchloride  (1)
  • 1
    ISSN: 1432-0428
    Keywords: Islet of Langerhans ; insulin secretion ; nitric oxide ; cyclic guanosine monophosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The involvement of nitric oxide as an intracellular messenger in the control of insulin secretion from pancreatic Beta cells was studied in rat islets of Langerhans by measuring: (i) nitric oxide generation in response to physiological insulin secretagogues; (ii) the effects of inhibitors of nitric oxide synthesis on insulin secretory responses to physiological secretagogues, and on insulin synthesis; (iii) changes in islet cyclic guanosine monophosphate in response to secretagogues; (iv) the effects of exogenous cyclic guanosine monophosphate and dibutyryl cyclic guanosine monophosphate on insulin secretion from electrically permeabilised islets and from intact islets, respectively. These studies produced no evidence that nitric oxide generation is required for the initiation of insulin secretion by common secretagogues. However, the results of our experiments suggest that the generation of nitric oxide may be involved in long-term, glucose-dependent increases in cyclic guanosine monophosphate content of islet cells, although the physiological relevance of these changes requires further investigation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 37 (1994), S. S30 
    ISSN: 1432-0428
    Keywords: Islets of Langerhans ; insulin secretion ; protein kinase A ; cyclic AMP ; calcium-calmodulin ; protein kinase C ; arachidonic acid ; nitric oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This review summarises briefly studies performed in the last 5–6 years concerning the role of second messengers in the regulation of insulin secretion, using intact and electrically permeabilized rat islets of Langerhans. It is concluded that cyclic AMP (through protein kinase A), calcium (through calcium-calmodulin dependent protein kinases) and diacylglycerol (through protein kinase C) may be important second messengers in modulating the effects of specific secretagogues on insulin release. However, recent studies strongly suggest that neither protein kinase A nor protein kinase C are directly involved in the regulation of insulin secretion by glucose. The possible involvement of other second messengers, nitric oxide and arachidonic acid, in the regulation of secretion is also briefly reviewed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0044-2313
    Keywords: Diphenoxyphosphorylchloride ; N′,N′-dialkyl-N-diphenoxyphosphoryl urea ; N-diphenoxyphosphoryl-N″,N″-dipropyl biuret ; X-ray crystal structure analysis ; n.m.r. spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Diphenoxyphosphorylchloride with N,N-disubstituted Ureas - Formation of Phosphorylated Biuret CompoundsN′,N′-disubstituted N-diphenoxyphosphorylureas, (PhO)2P(O)—NH—CO—NR1R2 (R1 = R2 = Et, 1; n-Pr, 2; n-Bu, 3; i-Bu, 4; R1 = Me and R2 = Ph, 5) as well as phosphorylated biuret compounds, (PhO)2P(O)—NH—CO—NH—CO—NR1R2 are obtained in the reaction of diphenoxyphosphorylchloride with N,N-disubstituted ureas and triethylamine. The biuret derivatives are formed via (PhO)2P(O)NCO. Their yield rises if the reaction is carried out without amine. The X-ray crystal structure analysis of (PhO)2P(O)—NH—CO—NH—CO—NPr2, 8, shows that dimers exist in the crystal with intermolecular as well as intramolecular hydrogen bonds. The framework formed by atoms P—N1—C1(O4)—N2—C2(O5)—N3(C3)C6 is planar. The existence of a rotation barrier along the bond C2-N3 was detected by NMR spectroscopy.
    Notes: Bei der Umsetzung von Diphenoxyphosphorylchlorid mit N,N-disubstituierten Harnstoffen in Gegenwart von Triethylamin treten neben N′,N′-disubstituierten N-Diphenoxyphosphorylharnstoffen, (PhO)2P(O)—NH—CO—NR1R2 (R1 = R2 = Et, 1; n-Pr, 2; n-Bu, 3; i-Bu, 4; R1 = Me u. R2 = Ph, 5), immer auch N″,N″-disubstituierte N-Diphenoxyphosphorylbiuret-Verbindungen, (PhO)2P(O)—NH—CO—NH—CO—NR1R2 auf. Sie entstehen über intermediär gebildetes (PhO)2P(O)NCO. Die Ausbeute an Biuretderivaten steigt, wenn ohne Aminzusatz gearbeitet wird. Die Röntgen-Kristallstrukturanalyse von (PhO)2P(O)—NH—CO—NH—CO—NPr2, 8, zeigt, daß im Kristall Dimere mit sowohl inter- als auch intramolekularen Wasserstoffbrücken vorliegen. Das Gerüst von 8 mit der Atomfolge P—N1—C1(O4)—N2—C2(O5)—N3(C3)C6 ist nahezu planar. NMR-Untersuchungen beweisen die Existenz einer Rotationsbarriere um die Bindung C2-N3.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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