title: 2,5-Di(tert-butyl)-1,4-benzohydroquinone--a novel inhibitor of liver microsomal Ca2+ sequestration.
abstract: Treatment of rat liver microsomes with 2,5-di(tert-butyl)-1,4-benzohydroquinone caused a dose-related inhibition (Ki congruent to 1 microM) of ATP-dependent Ca2+ sequestration. This was paralleled by a similar impairment of the microsomal Ca2+-stimulated ATPase activity. In contrast, the hydroquinose failed to induce Ca2+ release from Ca2+-loaded liver mitochondria (supplied with ATP), and inhibited neither the mitochondrial F1F0-ATPase nor the Ca2+-stimulated ATPase activity of the hepatic plasma membrane fraction. The inhibition of microsomal Ca2+ sequestration was not associated with any apparent alteration of membrane permeability or loss of other microsomal enzyme activities or modification of microsomal protein thiols. These findings suggest that 2,5-di(tert-butyl)-1,4-benzohydroquinone is a potent and selective inhibitor of liver microsomal Ca2+ sequestration which may be a useful tool in studies of Ca2+ fluxes in intact cells and tissues.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002451:Cell Compartmentation / Q000187:drug effects; D002462:Cell Membrane / Q000201:enzymology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006873:Hydroquinones / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism; D051381:Rats
chemical_list: D006873:Hydroquinones; C019359:2,5-di-tert-butylhydroquinone; D003577:Cytochrome P-450 Enzyme System; D000252:Calcium-Transporting ATPases; D002118:Calcium