Indomethacin-induced increase in noradrenaline turnover in some rat organs.
1 The effect of a prostaglandin synthesis inhibitor, indomethacin, on noradrenaline turnover rate in various rat tissues was determined from the product of the endogenous noradrenaline concentration and of the rate constant of (-)-[3H]-noradrenaline decline after injection of the labelled amine in tracer doses. 2 Treatment of the rats with indomethacin (5 mg/kg p.o. five times during 2.5 days) increased noradrenaline turnover rate 32-36% in submandibular gland, spleen and heart, and 4-17% in epididymal and subcutaneous adipose tissue. 3 The extrapolated [3H]-noradrenaline content at time 0 was greater in heart and adipose tissue of indomethacin-treated animals than in controls, while it was not significantly changed in spleen and salivary gland. 4 There was no apparent relationship between tissue concentrations of intravenously injected [14C]-indomethacin and the effect of indomethacin on noradrenaline uptake and turnover rate in the different tissues. 5 Indomethacin treatment did not affect monoamine oxidase and catechol O-methyl-transferase activities in the different tissues. 6 The results are consistent with the hypothesis that indomethacin increases noradrenaline turnover in the rat by blockade of a locally operating feed back inhibition of transmitter release by prostaglandins. However, additional effects, such as an increased impulse traffic, cannot be ruled out.
D000273:Adipose Tissue / Q000201:enzymology / Q000378:metabolism; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D013154:Spleen / Q000201:enzymology / Q000378:metabolism; D013268:Stimulation, Chemical; D013363:Submandibular Gland / Q000201:enzymology / Q000378:metabolism
D008995:Monoamine Oxidase; D002394:Catechol O-Methyltransferase; D009638:Norepinephrine; D007213:Indomethacin