Characterisation of androstenone metabolism in pig liver microsomes
Characterisation of androstenone metabolism in pig liver microsomes
复制标题
DOI：
10.1016/j.cbi.2003.12.002
复制
发表时间：
2004-03-15
影响因子：
5.1
通讯作者：
McGivan, JD
中科院分区：
文献类型：
--
作者：
Doran, E;Whittington, FA;McGivan, JD
雄烯酮（5 α-androst-16-en-3-one）是一种在睾丸中产生的类固醇信息素。雄甾烯酮与粪臭素（3-甲基吲哚）在某些雄性猪的脂肪组织中过量积累会导致“公猪臭味”。在离体猪肝细胞中，雄甾烯酮抑制细胞色素P450 PiE 1（CYP 2 E1）的表达，该酶主要负责粪臭素代谢。雄甾烯酮可在肝微粒体中代谢，但代谢途径尚未建立。我们研究了雄甾烯酮在脂肪组织中低水平和高水平的两个品种猪--大白色猪（LW）和梅山猪（M）肝微粒体中的代谢。雄甾烯酮在离体肝微粒体中主要以NADH作为辅因子还原为β-雄甾烯醇。在NADPH存在下，β-雄甾烯醇形成的速率非常低。在LW猪的微粒体中，雄烯酮形成β-雄甾烯醇的速率比M猪高6倍。3 β-羟基类固醇脱氢酶（3 β-HSD）被研究为催化猪肝中雄甾烯酮还原的酶的可能候选物。RT-PCR分析表明，LW猪和M猪3 β-羟类固醇脱氢酶基因的cDNA序列没有差异。然而，竞争性RT-PCR分析表明，3 β-羟基类固醇脱氢酶mRNA的表达量在LW的情况下，M猪相比，约高12倍。因此，猪肝微粒体中雄甾烯酮的代谢速率取决于肝脏3 β-羟基类固醇脱氢酶的表达水平。这种酶的差异表达可能是影响肝雄甾烯酮代谢速率的一个因素，这反过来又可能影响肝CYP 2 E1表达水平，从而影响肝粪臭素代谢速率。(C)2003爱思唯尔爱尔兰有限公司保留所有权利。
Androstenone (5alpha-androst-16-en-3-one) is a steroid pheromone produced in the testis. Excessive accumulation of androstenone together with skatole (3-methyl-indole) in the adipose tissue of some male pigs leads to "boar taint". In isolated pig hepatocytes androstenone represses the expression of cytochrome P450PiE1 (CYP2E1), the enzyme principally responsible for skatole metabolism. Androstenone can be metabolised in livermicrosomes but the pathway has not been established. We have investigated androstenone metabolism in liver microsomes from two breeds of pigs exhibiting low and high levels of androstenone in adipose tissue-Large White (LW) and Meishan (M), respectively. Androstenone was reduced in isolated liver microsomes mainly to beta-androstenol using NADH as a co-factor. The rate of beta-androstenol formation in the presence of NADPH was very low. In microsomes from LW pigs the rate of beta-androstenol formation from androstenone was six times higher than in M pigs. 3beta-hydroxysteroid dehydrogenase (3beta-HSD) was investigated as a likely candidate for the enzyme catalysing androstenone reduction in pig liver. RT-PCR analysis showed that there was no sequence difference in the cDNA encoding 3beta-hydroxysteroid dehydrogenase from LW and M pigs. However, competitive RT-PCR analysis showed that the expression of 3 P-hydroxysteroid dehydrogenase mRNA was about 12 times higher in the case of LW compared to M pigs. It is concluded that the rate of androstenone metabolism in pig liver microsomes is determined by the level of expression of hepatic 3beta-hydroxysteroid dehydrogenase. The differential expression of this enzyme could be a factor affecting the rate of hepatic androstenone metabolism which in turn may influence the level of hepatic CYP2E1 expression and hence the rate of hepatic skatole metabolism. (C) 2003 Elsevier Ireland Ltd. All rights reserved.