Hu Liangbiao, Monteiro Ana, Johnston Heather, King Peter, O'Shaughnessy Peter J
Division of Cell Sciences, University of Glasgow Veterinary School, Institute of Comparative Medicine, Bearsden Road, Glasgow, UK.
Reproduction. 2007 Oct;134(4):585-91. doi: 10.1530/REP-07-0133.
Fetal Leydig cells and fetal adrenocortical cells may share a common progenitor cell. Both cell types show several similarities, particularly in relation to their primary steroidogenic function. Differences in steroid secretion are largely due to the expression of 21-hydroxylase (CYP21A1) and 11beta-hydroxylase (CYP11B1) activity in the adrenal. To determine whether expression of these enzymes defines a clear difference between adrenocortical and Leydig cells, or is further evidence of a link between the cell types, we have measured Cyp21a1 and Cyp11b1 expression and related enzyme activity in the fetal testis. Expression of both Cyp21a1 and Cyp11b1 was clearly detectable in the fetal testis by RT-PCR and Southern blotting. Real-time PCR studies showed that Cyp11b1 was expressed only in the fetal/neonatal testis with no expression in the pubertal or post-pubertal animal. Cyp21a1 was also predominantly expressed in the fetal testis although some lower expression was also seen in the adult. Expression of Cyp21a1 and Cyp11b1 in neonatal testicular cells was unaffected by incubation in vitro with human chorionic gonadotrophin or ACTH. Using immunohistochemistry, CYP21A1 was localised to a subset of interstitial steroidogenic cells in the fetal testis although CYP11B1 was not detectable. Incubation studies showed that 21-hydroxylase activity was present in the tissue although 11beta-hydroxylase activity could not be detected. Results indicate that a subpopulation of steroidogenic cells in the fetal testis express Cyp21a1 and show 21-hydroxylase activity. This may provide further evidence of a link between fetal Leydig cells and adrenocortical cells but does not discount the possibility that these steroidogenic cells represent 'ectopic' adrenal cells.
胎儿睾丸间质细胞和胎儿肾上腺皮质细胞可能有共同的祖细胞。这两种细胞类型有几个相似之处，特别是在其主要的类固醇生成功能方面。类固醇分泌的差异很大程度上归因于肾上腺中21-羟化酶（CYP21A1）和11β-羟化酶（CYP11B1）活性的表达。为了确定这些酶的表达是否明确界定了肾上腺皮质细胞和睾丸间质细胞之间的差异，或者是否进一步证明了这两种细胞类型之间的联系，我们检测了胎儿睾丸中Cyp21a1和Cyp11b1的表达及相关酶活性。通过逆转录聚合酶链反应（RT-PCR）和Southern印迹法在胎儿睾丸中可清楚检测到Cyp21a1和Cyp11b1的表达。实时PCR研究表明，Cyp11b1仅在胎儿/新生儿睾丸中表达，在青春期或青春期后的动物中无表达。Cyp21a1也主要在胎儿睾丸中表达，尽管在成年动物中也有一些较低水平的表达。新生儿睾丸细胞中Cyp21a1和Cyp11b1的表达不受体外与人绒毛膜促性腺激素或促肾上腺皮质激素孵育的影响。使用免疫组织化学方法，CYP21A1定位于胎儿睾丸间质类固醇生成细胞的一个亚群，而CYP11B1未检测到。孵育研究表明，组织中存在21-羟化酶活性，但未检测到11β-羟化酶活性。结果表明，胎儿睾丸中的一个类固醇生成细胞亚群表达Cyp21a1并具有21-羟化酶活性。这可能进一步证明了胎儿睾丸间质细胞和肾上腺皮质细胞之间的联系，但并不排除这些类固醇生成细胞代表“异位”肾上腺细胞的可能性。
