摘要 :
AIM: It is known that thyroid hormones alter the bile acid metabolism in humans, however the effect on individual enzymes has been difficult to elucidate.This is mainly due to the lack of human liver cell lines producing bile acid...
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AIM: It is known that thyroid hormones alter the bile acid metabolism in humans, however the effect on individual enzymes has been difficult to elucidate.This is mainly due to the lack of human liver cell lines producing bile acids. We used cultures of primary human hepatocytes to study the effects of triiodothyronine (T3) on bile acid synthesis.METHODS: Primary hepatocytes were isolated from liver tissue obtained from three different patients undergoing liver resection due to underlying malignancy. The hepatocytes were cultured under serum-free conditions and treated from d 1 to d 5 with culture containing 0.1-1000 nmol/L of T3. Bile acid formation and mRNA levels of key enzymes were analysed.RESULTS: The lowest concentration of T3 decreased cholic acid (CA) formation to 43%-53% of controls and chenodeoxycholic acid (CDCA) to 52%-75% of controls on d 5. The highest dose further decreased CA formation to 16%-48% of controls while CDCA formation remained at 50%-117% of controls. Expression of mRNA levels of cholesterol 7α-hydroxylase (CYP7A1) and sterol 12α-hydroxylase (CYP8B1) dose-dependently decreased.Sterol 27-hydroxylase (CYP27A1) levels also decreased,but not to the same extent.CONCLUSION: T3 dose-dependently decreased total bile acid formation in parallel with decreased expression of CYP7A1 and CYP8B1. CA formation is inhibited to a higher degree than CDCA, resulting in a marked decrease in the CA/CDCA ratio.
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摘要 :
目的:探讨醛同酮瘤中CYP11B2,CYP11B1基因多态性与CYP11B2基因mRNA表达及术前血浆醛固酮浓度、收缩压、舒张压等临床表型的关系.方法:20例正常肾上腺和69例醛固酮瘤组织标本,分别取自2006年5月～2007年11月在华中科技大学同济医学院附属同济医院泌尿外...
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目的:探讨醛同酮瘤中CYP11B2,CYP11B1基因多态性与CYP11B2基因mRNA表达及术前血浆醛固酮浓度、收缩压、舒张压等临床表型的关系.方法:20例正常肾上腺和69例醛固酮瘤组织标本,分别取自2006年5月～2007年11月在华中科技大学同济医学院附属同济医院泌尿外科行肾癌根治术和肾上腺手术切除的患者.采用Taqman探针法检测DNA多态性,包括CYP11B2基因的rs1799998、rs4539及CYP11B1基因的rs6410和rs6387;采用两对独立的PCR检测CYP11B2基因intron2多态性(野生型/转位型).采用syb green Real time RT-PCR检测CYP11B2基因mRNA表达.在R statistics program 2.7.0程序包中使用SNPassoc 1.5-3和Haplo.stats 1.3.8分析CYP11B2和CYP11B1基因多态性及单体型与CYP11B2基因表达量和血浆醛固酮浓度、收缩压、舒张压等临床表型的关系.结果:单体型分型中,Global Score统计显示:CYP11B2-CYP11B1单体型与CYP11B2mRNA表达量增加相关(global-stat=16.175,df=8,P=0.04),与血清醛固酮水平相关(globalstat=20.407,df=8,P=0.009).但与收缩压和舒张压不相关(分别P=0.34,P=0.54);多元回归分析中发现单体型H1(AGAConvT)和H3(AGAWtC)与CYP11B2基因mRNA的表达上调相关(经过Bonferroni校正后分别P=0.002;P=0.003),而H6(AGGWtT)、H10(AAAWtT)和H16(GAAWtT)与过多的醛同酮分泌相关(经过Bonferroni校正后分别P＜0.0005;P=0.002;P=0.0015);但未见有单体型与收缩压和舒张压相关(均P＞0.05).结论:CYP11B2和CYP11B1基因多态性可能通过上调CYP11B2的表达,导致醛固酮瘤患者血清醛固酮水平的升高.
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