REGULATORY EXPRESSION OF CYP2B GENE FAMILY BY HORMONE
1994 Volume 9 Issue supplement Pages 164-167
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1994 Volume 9 Issue supplement Pages 164-167
Hormonal effects on expression of constitutive and phenobarbitalinducible Cyp2b9/10 species were investigated in mouse hepatocytes in primary culture and in vivo. Although the expression decreased rapidly in monolayer-cultured cells, it maintained at equivalent levels to that in in vivo when the cells were cultured as spheroids(multiclellular aggregate). In control liver more Cyp2b9 than Cyp2b10 mRNA and protein were expressed, whereas their amounts in cultured cells showed the reverse order because of more rapid decline of Cyp2b9 in culture. Dexamethasone at 10-6 or 10-7 M induced the mRNA. Without dexamethasone addition of phenobarbital scarcely induced it. Although expression of rat C YP2B1/2, orthologous to mouse Cyp2b9/10, is higher in male, female mouse expresses them higher. Beta-estradiol at 10-5 or 10-6 M induced the Cyp2b9/10 and the induced mRNA amounts corresponded to those by 10-3 M phenobarbital. Estrone also showed an inducing potency at 10-6 M. These observations indicate that constitutive expression of mouse Cyp2b9/10 may be regulated by glucocorticoid and female hormones.
