Key Laboratory of Basic Pharmacology of Guizhou, Zunyi Medical College , Zunyi , China .
Chronobiol Int. 2013 Nov;30(9):1135-43. doi: 10.3109/07420528.2013.805762. Epub 2013 Aug 8.
Sex differences and circadian variation are two major factors that affect the expression of drug-processing genes. This study aimed to examine sex differences in the circadian variation of hepatic cytochrome P450 (Cyp) genes and corresponding nuclear receptors. Adult mice were acclimated to environmentally controlled facilities for 2 wks, and livers were collected every 4 h during a 24-h period. Total RNA and protein were isolated and subjected to real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis. The mRNA expression of the aryl hydrocarbon receptor (AhR) and AhR-regulated Cyp1a1 and Cyp1a2 were higher in females and higher during the light phase. The mRNA expression of constitutive and rostane receptor (CAR) and CYP2B10 protein was female-predominant and higher in the dark phase. Pregnane X receptor (PXR) peaked around 18:00 h, but PXR-regulated Cyp3a11 and Cyp3a25 were higher at 10:00 h, without apparent sex dimorphism at protein levels. Peroxisome proliferator-activated receptor-α (PPARα), Cyp4a10, and Cyp4a14 were higher in females and peaked between 14:00 and 18:00 h. The mRNA levels of farnesoid X receptor (FXR), Cyp7a1, and Cyp27a1 peaked around 18:00 h and CYP7A1 protein was higher during the dark phase and higher in females. Cyp7b1(male-predominant) and Cyp2a4 (female-predominant) both showed circadian variation. Circadian variation of hepatic clock genes such as nuclear receptor Rev-erbα, cryptochrome 1 (Cry1), and brain muscle ARNT-like protein 1 (Bmal1) showed distinct patterns. Sex differences and circadian rhythmicity of Cyp genes and corresponding nuclear receptors exist in mouse liver that could impact xenobiotic metabolism and toxicity at different times of the day.
性别差异和昼夜节律变化是影响药物处理基因表达的两个主要因素。本研究旨在研究肝细胞色素 P450（Cyp）基因和相应核受体昼夜节律变化中的性别差异。成年小鼠适应环境控制设施 2 周，在 24 小时期间每隔 4 小时采集肝脏。分离总 RNA 和蛋白质，并进行实时逆转录聚合酶链反应（RT-PCR）和 Western blot 分析。芳香烃受体（AhR）和 AhR 调节的 Cyp1a1 和 Cyp1a2 的 mRNA 表达在女性中更高，并且在光相期间更高。组成型和罗斯坦受体（CAR）和 CYP2B10 蛋白的 mRNA 表达以雌性为主，在暗相期间更高。妊娠相关蛋白 X 受体（PXR）在 18:00 左右达到峰值，但 PXR 调节的 Cyp3a11 和 Cyp3a25 在 10:00 左右更高，在蛋白质水平上没有明显的性别二态性。过氧化物酶体增殖物激活受体-α（PPARα）、Cyp4a10 和 Cyp4a14 在女性中更高，在 14:00 至 18:00 之间达到峰值。法尼醇 X 受体（FXR）、Cyp7a1 和 Cyp27a1 的 mRNA 水平在 18:00 左右达到峰值，CYP7A1 蛋白在暗相期间更高，在女性中更高。Cyp7b1（雄性为主）和 Cyp2a4（雌性为主）均表现出昼夜节律变化。肝时钟基因如核受体 Rev-erbα、隐色体 1（Cry1）和脑肌肉 ARNT 样蛋白 1（Bmal1）的昼夜变化表现出不同的模式。Cyp 基因和相应核受体在小鼠肝脏中存在性别差异和昼夜节律性，这可能会影响不同时间的外源性代谢物和毒性。
