Carrasco M, Gaule C, Vega P, del Villar E
Servicio de Medicina Interna, Hospital Regional de Copiapó.
Rev Med Chil. 1992 May;120(5):539-44.
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.
细胞色素P - 50是一种众所周知的参与外源性物质代谢的物质，同时也是肝毒性物质和致癌剂的激活剂或失活剂。H2拮抗剂西咪替丁、法莫替丁和雷尼替丁被用于抑制大鼠肝脏中的细胞色素P - 450。给予200毫克西咪替丁后，通过氨基比林的去甲基化证明，体外细胞色素P - 450抑制率为85%，体内抑制率为50%。通过差示吸收光谱（II型）进一步证实了抑制作用。法莫替丁或雷尼替丁的抑制百分比低于西咪替丁。西咪替丁对微粒体氧化系统的抑制可能导致超氧自由基产生减少，并防止肝脏中被激活的有毒物质引起的损伤。
