植物雌激素对体外培养的大鼠睾丸间质细胞分泌睾酮的作用

目的:研究植物雌激素(大豆苷元、染料木素)对睾丸间质细胞分泌睾酮的刺激作用,并初步研究其可能的分子作用机制。方法:采用Percoll不连续密度梯度离心,分离获得3月龄Sprague-Dawley(SD)大鼠的睾丸间质细胞。以人绒毛膜促性腺激素(hCG)为阳性对照药物,测定不同浓度(0、0.02、0.1、0.5、1、5μmol/L)大豆苷元、染料木素对睾丸间质细胞分泌睾酮的影响。RT-PCR检测睾酮生物合成过程中胆固醇侧链裂解酶细胞色素P450(P450scc)的表达。结果:0.1μmol/L的染料木素能显著刺激原代大鼠睾丸间质细胞的睾酮分泌,RT-PCR结果显示染料木素能显著上调睾酮合成过程中P450sccmRNA的表达。在较高浓度下(5μmol/L),大豆苷元和染料木素均能抑制睾丸间质细胞分泌睾酮。结论:染料木素在低浓度下(0.1μmol/L)显著促进睾丸间质细胞分泌睾酮,但随着浓度的增加(5μmol/L),大豆苷元和染料木素均显著抑制Leydig细胞的睾酮分泌。     

Cox7a2对睾酮合成及StAR、P450scc和3β-HSD蛋白表达影响研究

目的研究Cox7a2在TM3小鼠睾丸Leyidg细胞中过农达对LH诱导的睾酮合成及对StAR(睾酮合成调节关键蛋白),P450scc(胆同醇侧链裂解酶),3β—HSD(3β-羟基甾脱氢酶)蛋白表达的影响。方法构建Cox7a2荧光表达载体,转染TM3小鼠睾丸Leydig细胞,融合蛋白表达及LH诱导刺激后,ELISA测定细胞上清液中睾酮含量,Western blot检测StAR蛋白、P450scc和3β-HSD酶的表达变化。结果Cox7a2在TM3小鼠睾丸Leydig细胞中过表达抑制LH诱导的睾酮合成,降低StAR蛋白的表达,对P450scc和3β-HSD的蛋白表达没有明显影响。结论在TM3小鼠睾丸Leydig细胞中,Cox7a2至少通过抑制类固醇快速调节蛋白StAR的表达,进而抑制LH诱导的睾酮合成。     

类固醇生成因子—1与青春期小鼠睾丸P450scc mRNA水平的相关性研究

细胞色素Ｐ４５０胆固醇侧链裂解酶是催化胆固醇转化为类固醇的关键酶,其活性受到类固醇生成因子的调节。本研究应用定量ＰＣＲ的方法比较了５天,２０天,２５天和３０天正常小鼠睾丸中Ｐ４５０ｓｃｃ ｍＲＮＡ与ＳＦ－１ ｍＲＮＡ的水平。结果显示;从２５天起,小鼠睾丸内Ｐ４５０ｓｃｃ ｍＲＮＡ与ＳＦ－１ｍＲＮＡ的总水平同步升高,揭示了ＳＦ－１对青春期小鼠Ｐ４５０ｓｃｃ的调节作用。     

老年大鼠睾丸间质细胞形态及睾酮合成功能变化的研究

目的 探讨衰老对睾丸间质细胞的形态及功能的影响.方法 青年(3月龄)及老年(24月龄)清洁级雄性SD大鼠各10只,麻醉后取血清检测总睾酮浓度,取睾丸组织用HE染色观察睾丸组织形态学变化,并用电镜观察睾丸间质细胞的超微结构改变.通过密度梯度离心分离原代睾丸间质细胞,并用LH刺激睾酮分泌后用Western blot比较青年组和老年组睾丸间质细胞类固醇合成快速调节蛋白(steroidogenic acute regulatory protein,StAR)表达水平的差异,并用ELISA法检测其睾酮分泌的差异.结果 HE染色显示老年大鼠睾丸呈老年退行性改变,电镜下观察到老年大鼠睾丸间质细胞线粒体水肿,线粒体嵴消失.老年大鼠血清睾酮水平显著低于青年组(P＜ 0.05).原代培养的睾丸间质细胞无论LH刺激与否,老年组细胞上清中睾酮浓度及StAR蛋白表达水平均显著低于青年组(LH刺激时P＜0.01,无LH刺激时P＜0.05).结论 衰老造成的睾丸间质细胞线粒体水肿及LH诱导的StAR蛋白表达水平下降与其睾酮合成能力降低密切相关.     

子宫内膜细胞色素P450芳香化酶的表达研究进展

细胞色素 P45 0芳香化酶 ( aromatasecytochrome P45 0 ,P45 0 arom)能催化 C19雄激素转化为雌激素 ,是雌激素合成的关键酶之一。P45 0 arom位于细胞内质网 ,在体内多种雌激素合成部位表达 ,如卵巢颗粒细胞、脂肪组织、胎盘合体滋养层细胞、脑细胞等。近年的研究发现 P45 0 arom在子宫内膜上也有表达 ,能促进子宫内膜局部雌激素的转化 ,现对其在子宫内膜的研究进展综述如下。细胞色素 P45 0芳香化酶的结构特征P45 0 arom与其它细胞色素 P45 0异构体的结构类似。C端为血红素结合区 ,该区含有保守的半胱氨酸残基 ,可作为含铁血红素的第 5…     

细胞色素P450芳香化酶在大鼠多囊卵巢中的表达及意义

目的检测细胞色素P450芳香化酶(P450 arom)在大鼠多囊卵巢颗粒细胞中的表达水平,探讨P450 arom与多囊卵巢综合征(PCOS)的关系。方法应用半定量逆转录-聚合酶链反应(RT-PCR)检测PCOS实验组及正常对照组大鼠卵巢组织中P450 arom基因(CYP19)的表达;采用链霉素抗生物素蛋白-过氧化物酶(SP)法对大鼠卵巢组织中P450 arom进行检测。结果实验组和对照组卵巢组织中CYP19基因,相对表达强度分别为(0.138±0.072)和(0.759±0.236),差别有显著性意义(P<0.01);实验组中原始卵泡、初级卵泡和成熟卵泡比较,P450 arom蛋白表达下降(P<0.05)。对照组间初级卵泡、次级卵泡和成熟卵泡比较,arom蛋白表达有显著性差异(P<0.05)。结论P450 arom mRNA在PCOS大鼠卵巢组织中呈低表达;P450 arom蛋白在PCOS大鼠卵巢初级卵泡和成熟卵泡中表达下降;PCOS的发生可能与P450 arom在mRNA和蛋白水平的表达下调有关。     

内源性睾酮抑制对大鼠睾丸内α-catenin表达的影响

目的:检测十一酸睾酮注射致内源性睾酮抑制的大鼠睾丸内α-caten in的表达情况。方法:成年雄性SD大鼠10只,随机分为对照组(肌注生理盐水)和睾酮组[肌注十一酸睾酮19 mg/(kg.15 d)],共130 d。制作睾丸石蜡切片,采用抗α-caten in多克隆抗体进行免疫组化染色。结果:在对照组中,α-caten in主要表达于精子细胞顶体、管周肌样细胞和Leyd ig细胞胞质。睾酮组的Leyd ig细胞明显萎缩,-αcaten in的表达明显减弱或消失,而精子细胞顶体和管周肌样细胞胞质的-αcaten in表达无明显改变。结论:内源性睾酮抑制所致生精细胞排列疏松或脱落与粘附分子-αcaten in的表达无关。-αcaten in有可能成为识别Leyd ig细胞的标记物。     

细胞色素P450的检测方法及其与肝脏疾病的联系

细胞色素P450与外来化合物的生物转化及内源性物质的代谢有关。细胞色素P450的酶活性降低将直接或间接引起肝脏的解毒能力下降,加重肝脏损害。本文就细胞色素P450的检测方法及其与肝脏疾病的联系,做一简要综述。     

细胞色素P450的检测方法及其与肝脏疾病的联系

细胞色素P450与外来化合物的生物转化及内源性物质的代谢有关.细胞色素P450的酶活性降低将直接或间接引起肝脏的解毒能力下降,加重肝脏损害.本文就细胞色素P450的检测方法及其与肝脏疾病的联系,做一简要综述.     

大鼠无肝状态下七氟醚代谢相关药酶细胞色素P450 2E1的表达

目的 探讨七氟醚代谢相关药酶细胞色素P450 2E1(CYP2E1)在肝移植无肝期肝外组织的表达变化.方法 24只SD大鼠随机均分为无肝期30 min组(A组)和60 min组(B组)和对照组(C组),各组均吸入七氟醚麻醉.A和B组通过阻断肝门模拟肝移植无肝期,相应时间终点截取各组大鼠肝外组织(小肠、肺脏和肾脏),C组麻醉后直接处死,截取大鼠肝外组织(小肠、肺脏和肾脏)应用RT-PCR、Western blot和免疫组化检测七氟醚代谢相关药酶CYP2E1在其中的表达.结果 A和B组肝外各组织中CYP2E1的表达显著强于C组(P<0.05);CYP2E1在小肠和肾脏的单一细胞中表达,而在肺脏的多种细胞中表达.结论 大鼠无肝状态下,CYP2E1在肝外器官组织中表达增多,可能促进七氟醚的肝外代谢;肺脏可能是最主要的肝外代谢器官.     

Integration of new regulatory strategies into the network of an endocrine control system: limitation of androgen secretion by rat testis is achieved by substrate-dependent modulation of P450XVII enzyme concentration and catalytic efficiency.

In addition to the well-known control circuits involved in the regulation and adaptation of testicular androgen biosynthesis, it is proposed that two new control strategies are involved in the maintenance of steady-state testosterone secretion rates by testicular Leydig cells. Cytochrome P450XVII (steroid-17 alpha-monooxygenase/steroid-17,20-lyase), one key enzyme in steroid hormone biosynthesis, responds to external human choriogonadotropin stimulation with an oxygen-dependent and substrate flux-dependent inactivation and decomposition, and increased substrate availability decreases the efficiency of androgen formation in favour of abortive intermediate leakage. These results are discussed as a paradigm of substrate-dependent modulation of cytochrome P450 activities.     

Recovery of hepatic function determined by cytochrome P450-dependent drug metabolism lags after compensatory hepatic volume changes after portal vein ligation in rats

BACKGROUND: Clinically, portal vein embolization has been proven to be useful as a preoperative treatment for major hepatic surgeries with impaired liver function. However, its effects on the metabolism and elimination of various drugs after portal vein embolization or ligation remain to be elucidated. MATERIALS AND METHODS: A portal vein branch that perfuses the central and left lobes of the liver of male Wistar rat was ligated, and changes in the weights of ligated and nonligated lobules as well as hepatic levels and activities of cytochrome P450 (CYP) isoforms, such as CYP3A2 and CYP2C11, were determined. To evaluate in vivo the effect of PVL on hepatic drug metabolism, the narcotic activity (sleep time) of midazolam, a specific substrate for CYP3A2, was measured. RESULTS: Although plasma levels of alanine aminotransferase and hepatic weight returned to basal levels at day 7 after the portal vein ligation, hepatic activities of CYP3A2 and CYP2C11 still remained low (53% and 54% of control levels, respectively), and returned to their initial levels after about day 14. The metabolism of midazolam was prolonged by approximately three times at day 7 after ligation and returned to basal levels at day 14. CONCLUSIONS: Because hepatic CYP-dependent drug metabolism by CYP isoforms recovered more slowly than the apparent recovery of hepatic volume and plasma alanine aminotransferase levels, the therapeutics of drugs metabolized by the CYP isoforms should be used carefully in patients who receive major hepatectomy with portal vein branch embolization.     

Cytochrome P450 3A5 expression in the kidneys of patients with calcineurin inhibitor nephrotoxicity.

BACKGROUND: Nephrotoxicity secondary to calcineurin inhibitors is common in renal transplant recipients, occurring in 76-94% of patients. The role of drug transporters (P-glycoprotein) and drug metabolizing enzymes (cytochrome P450) as predisposing factors toward nephrotoxicity or its prevention has not been thoroughly examined. METHODS: The objective of this study was to analyse cytochrome P450 3A5 (CYP3A5) expression in kidneys of solid organ recipients by immunohistochemistry to determine if there is an association between expression of this enzyme and calcineurin inhibitor toxicity. Transplant recipients were compared with a control group. RESULTS: Apical tubular plasma membrane staining for CYP3A5 was present in 62% of study and 100% of control biopsies (P=0.0012). Proximal and distal tubular nuclear staining intensity was similar between groups. Cytoplasmic staining in both the proximal (2.1+/-0.9 vs 1.4+/-0.9) and distal (2.8+/-0.5 vs 1.8+/-1.1) tubules was greater in the control vs study population specimens, respectively (P=0.0093 and P=0.0005, respectively). Regression models that controlled for use of CYP3A inhibiting and inducing medications, age, gender, race and glomerular filtration rate did not predict differences between study groups with regard to staining locations and intensity, except for the cytoplasm of the distal tubule, where intensity of staining was significantly lower in the study group (0.9+/-0.3; P=0.002). CONCLUSIONS: This study showed decreased expression of CYP3A5 in nephrotoxic biopsies as compared with a control group. Our data suggest that the relationship between reduced presence of CYP3A5 in the kidney tubules and nephrotoxicity should be further explored to elucidate the role of this enzyme in mediating toxicity.     

实验性精索静脉曲张大鼠血清及睾内睾酮的变化

目的:研究精索静脉曲张(VC)大鼠模型对血清T和睾丸内T的影响。方法:通过部分结扎左肾静脉建立SD大鼠VC模型20只;假手术组SD大鼠20只为对照组。模型建立后4、8周取静脉血,并取部分睾丸组织匀浆提取上清液,放免法测定血清及睾丸内T浓度。结果:血清T:实验组4、8周与同期对照组相比有下降趋势,但没有统计学意义。双侧睾丸内T水平:实验组4周与对照组4周相比下降,但无统计学意义(P>0.05);实验组8周与对照组8周相比下降,具有统计学意义(P<0.01)。结论:在8周内实验性大鼠VC并没有引起血清T的降低,但可以导致双侧睾丸内T降低。     

电磁辐射对睾丸及附睾精子生物学效应的研究现状

睾丸对电磁辐射具有高度敏感性,精子是雄性遗传信息的传递者,电磁辐射可致睾丸结构和功能损伤以及附睾精子活力下降、畸形率增加、超微结构改变、遗传物质损伤。而生精细胞能量代谢障碍、脂质过氧化增强、炎症因子高表达和基因转录异常在其损伤发生发展过程中发挥重要作用。现对该方面的研究进展及相应的防治措施进行综述。