title: A method for stabilization of monoamine oxidases in homogenates of rat intestine epithelium.
abstract: In a homogenate of epithelium isolated from the small intestine of male Wistar rats, the amine oxidase activity with 10(-3)M tyramine was 9200 +/- 200 nmol (g tissue)-1 h-1 of which 91% was due to the A form of monoamine oxidase (MAO) and 9% to the B form. Semicarbazide-sensitive amine oxidase activity was not detected with either 10(-3)M tyramine or 10(-4)M benzylamine as substrate. However, it was detectable in the homogenate of the gut residue where the activity with 10(-4)M benzylamine was 3600 +/- 200 nmol (g tissue)-1 h-1. The MAO activity, in homogenates of epithelium prepared with 0.1 M sodium phosphate pH 7.4, was stable at 4 degrees C for at least 6 h whilst at minus 20 degrees C it decreased by 70% within 24 h. Incorporation of 10% (v/v) glycerol into the homogenization medium stabilized the enzymes. The total activity and proportions due to MAO-A and MAO-B and kinetic constants for tyramine and 5-hydroxytryptamine, did not alter during 5 weeks storage at -20 degrees C. The ability to store tissue homogenates should facilitate studies of intestinal amine oxidases.
mesh_terms: D000818:Animals; D003521:Cyclopropanes / Q000494:pharmacology; D004848:Epithelium / Q000201:enzymology; D005990:Glycerol / Q000494:pharmacology; D066298:In Vitro Techniques; D007422:Intestines / Q000201:enzymology*; D008297:Male; D008995:Monoamine Oxidase / Q000302:isolation & purification*; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism; D014439:Tyramine / Q000378:metabolism
chemical_list: D003521:Cyclopropanes; D008996:Monoamine Oxidase Inhibitors; D012701:Serotonin; C000434:Lilly 51641; D008995:Monoamine Oxidase; D005990:Glycerol; D014439:Tyramine