The histaminase activity of rat white adipocytes.
OBJECTIVE
Investigate the reaction conditions which allow the measurement of high affinity histamine oxidation.


METHODS
Isolated rat white adipocytes.


METHODS
The histaminase activity of rat white adipocytes and its inhibition by B24 and MDL 72274 was measured fluorimetrically or radiochemically in different experimental conditions.


RESULTS
Histamine oxidation by rat white adipocytes is enhanced by elevated pH and by the presence of bicarbonate ions. Under these conditions the oxidative deamination of histamine by white adipocytes, becomes comparable to that of other histaminases, suggesting that this amine oxidase activity may play a role in the catabolism of histamine in vivo. The specific semicarbazide-sensitive amine oxidase (SSAO) inhibitors MDL 72274 and B24 inhibit the oxidation of both histamine and benzylamine by the adipocyte preparation.


CONCLUSIONS
Although there are kinetic differences between the behaviour of these two amine substrates, these results would be consistent with a SSAO being responsible for both activities.
Raimondi
L
L
Department of Pharmacology, University of Florence, Italy.
Banchelli
G
G
Ignesti
G
G
Pirisino
R
R
Conforti
L
L
D017667:Adipocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D000498:Allyl Compounds / Q000494:pharmacology; D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001547:Benzaldehydes / Q000378:metabolism; D001596:Benzylamines / Q000737:chemistry / Q000378:metabolism; D001639:Bicarbonates / Q000737:chemistry / Q000494:pharmacology; D002250:Carbon Radioisotopes; D002469:Cell Separation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006632:Histamine / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007553:Isotope Labeling; D008297:Male; D017830:Octoxynol / Q000737:chemistry; D010084:Oxidation-Reduction; D011437:Propylamines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
C094718:3,5-diethoxy-4-aminomethylpyridine; D000498:Allyl Compounds; D001547:Benzaldehydes; D001596:Benzylamines; D001639:Bicarbonates; D002250:Carbon Radioisotopes; D004791:Enzyme Inhibitors; C090015:MDL 72274A; D011437:Propylamines; D011725:Pyridines; D006632:Histamine; D017830:Octoxynol; C030796:benzylamine; D006631:Amine Oxidase (Copper-Containing); C032175:benzaldehyde