Fetal expression of GnRH and GnRH receptor genes in rat testis and ovary
Fetal expression of GnRH and GnRH receptor genes in rat testis and ovary
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DOI：
10.1677/joe.0.1590179
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发表时间：
1998-10-01
影响因子：
4
通讯作者：
Kottler, ML
中科院分区：
文献类型：
--
作者：
Botté, MC;Chamagne, AM;Kottler, ML
性腺促性腺激素释放激素受体（GnRH-R）的鉴定和成年大鼠性腺中GnRH激动剂对类固醇生成的直接抑制作用的证据，使人们相信局部分泌的GnRH或GnRH样肽在性腺内的作用。利用逆转录-聚合酶链反应结合Southern杂交和测序技术，我们在大鼠胚胎和成年的卵巢和睾丸中发现了一种完全加工的GnRH信使RNA（mRNA），其序列在成年睾丸中与在下丘脑中发现的序列相同，我们还在睾丸中检测到，但在卵巢中没有，用斑点杂交技术研究了大鼠性腺发育过程中GnRH和GnRH-R基因表达的变化。在此期间，标准化为总RNA的亲环蛋白mRNA水平保持不变。因此，我们使用亲环素作为内标。GnRH mRNA在卵巢中检测到的18.5 dpc，4天后，在睾丸中，和相似的水平，发现在两种性别在出生时。GnRH-R mRNA在14.5 dpc时存在于睾丸中，在15.5 dpc时存在于卵巢中，在21.5 dpc时睾丸中的水平是卵巢中的2.4倍。GnRH和GnRH-R mRNA水平增加，在两种性别的胎儿发育后期，但这种增加出现在卵巢比睾丸早两天，从而支持的假设，GnRH和GnRH-R基因的表达在胎儿发育过程中的性别依赖性的方式进行调节。在所有情况下，GnRH和GnRH-R的表达先于性腺中的促性腺激素受体和垂体促性腺激素分泌的启动。
The identification of gonadal gonadotropin-releasing hormone receptors (GnRH-R) and evidence of direct inhibitory effects of GnRH agonists upon steroidogenesis in adult rat gonads, lend credence to a putative intragonadal role of a locally secreted GnRH or GnRH-like peptide. Using reverse transcription-polymerase chain reaction followed by Southern blot hybridization and sequencing, we identified, both in the ovary and in the testis of fetal and adult rats, a fully processed GnRH messenger RNA (mRNA), the sequence of which, in adult testis, was identical to that found in the hypothalamus, We also detected in the testis, but not in the ovary, a transcript containing the first intron.The ontogeny of GnRH and GnRH-R gene expression was studied in rat gonads from 14.5 to 21.5 days post-coitum (dpc), using dot blot hybridization of total RNA. During this period, the levels of cyclophilin mRNA normalized to total RNA remained unchanged. Thus, we used cyclophilin as an internal standard. GnRH mRNA was detected in the ovary at 18.5 dpc, four days later than in the testis, and similar levels were found in both sexes at birth. GnRH-R mRNA was present at 14.5 dpc in the testis and at 15.5 dpc in the ovary, with the levels at 21.5 dpc being 2.4 times higher in the testis than in the ovary. GnRH and GnRH-R mRNA levels increased in both sexes in late fetal development, but this increase appeared two days sooner in the ovary compared with the testis, thus supporting the hypothesis that expression of the GnRH and GnRH-R genes is regulated in a sex-dependent manner during fetal development. In all cases, expression of GnRH and GnRH-R preceded gonadotropin receptors in the gonads and initiation of gonadotropin secretion by the pituitary.