[H2 antagonists as inhibitors of cytochrome P-450 in rat liver: in vitro and in vivo effects].
Cytochrome P-50 is a well known participant in the metabolism of xenobiotics as well as an activator or inactivator of hepatotoxic substances and carcinogenic agents. H2 antagonists, cimetidine, famotidine and ranitidine were used to inhibit cytochrome P-450 in rat liver. After 200 mg cimetidine, 85% inhibition of cytochrome P-450 in vitro and 50% in vivo were demonstrated through demethylation of aminopyrine. Inhibition was further confirmed by differential absorption spectra (Type II). The percentage inhibition obtained with famotidine or ranitidine were lower than those obtained with cimetidine. Inhibition of the microsomal oxidative system by cimetidine could lead to decreased production of superoxide radicals and protection against damage induced by toxic agents activated in the liver.
Servicio de Medicina Interna, Hospital Regional de Copiapó.
M
M
Carrasco
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C
Gaule
P
P
Vega
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E
del Villar
D000284:Administration, Oral; D000632:Aminopyrine / Q000378:metabolism; D000818:Animals; D001711:Biotransformation / Q000187:drug effects; D002927:Cimetidine / Q000494:pharmacology; D065607:Cytochrome P-450 Enzyme Inhibitors; D004790:Enzyme Induction / Q000187:drug effects; D015738:Famotidine / Q000494:pharmacology; D006420:Hemeproteins / Q000378:metabolism; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D008297:Male; D008745:Methylation / Q000187:drug effects; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors; D010084:Oxidation-Reduction; D011899:Ranitidine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013481:Superoxides / Q000378:metabolism
D065607:Cytochrome P-450 Enzyme Inhibitors; D006420:Hemeproteins; D006635:Histamine H2 Antagonists; D000632:Aminopyrine; D013481:Superoxides; D015738:Famotidine; D002927:Cimetidine; D011899:Ranitidine; D006899:Mixed Function Oxygenases
Antagonistas H2, como inhibidores del citocromo P-450 en hígado de ratas: efecto in vitro e in vivo.