Cytochemical demonstration of an enzymatic production of hydrogen peroxide on the surface of isolated thyroid capillaries.
By means of a cytochemical technique, hydrogen peroxide formation was located on the endothelial cell surface (predominantly the luminal aspect) of capillaries obtained by collagenase digestion of rat thyroid. The cyanide-insensitive H2O2 formation required aerobic conditions and NAD(P)H as substrate. FAD could also stimulate the reaction, but not xanthine. The cytochemical reaction was blocked by a non-penetrating protein inhibitor. The observations are interpreted as evidence of a plasmalemma-bound H2O2-generating enzyme. The findings indicate that microvascular endothelial cells are involved in the release of activated oxygen species, which might have important pathophysiologic implications.
D002731:4-Chloromercuribenzenesulfonate / Q000494:pharmacology; D000693:Anaerobiosis; D000818:Animals; D002196:Capillaries / Q000378:metabolism*; D002374:Catalase / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D004727:Endothelium / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000494:pharmacology; D006651:Histocytochemistry; D006861:Hydrogen Peroxide / Q000378:metabolism*; D009243:NAD / Q000494:pharmacology; D051381:Rats; D013961:Thyroid Gland / Q000098:blood supply*
D009243:NAD; D005182:Flavin-Adenine Dinucleotide; D002731:4-Chloromercuribenzenesulfonate; D006861:Hydrogen Peroxide; D002374:Catalase