Onagbesan O M, Safi M, Decuypere E, Bruggeman V
Laboratory for Physiology and Immunology of Domestic Animals, Catholic University of Leuven, Heverlee, Belgium.
Mol Reprod Dev. 2004 Jul;68(3):319-26. doi: 10.1002/mrd.20087.
Dimeric inhibins and activins are barely detectable in the plasma during prepubertal development of male and female chickens. This may be misconstrued to indicate that the proteins are not produced in the gonads and have no functional significance during this period. Very few studies have actually determined the mRNA expression profile of the inhibin and activin subunits in the gonads prior to puberty in order to establish their secretion at the local level and postulate potential roles for the inhibin and activins at this developmental stage. In this study, the expression of the mRNA for the alpha-, betaA-, and betaB-subunits was determined in the ovary and testis of chickens during prepubertal development. Gene expression was determined at 3, 5, 6, 8, 10, 12, 16, and 18 weeks of age by RT-PCR. Messenger RNA level was quantified by competitive RT-PCR at 3, 6, 12, and 18 weeks of age in order to detect any changes with development, suggest potential relationship to the profile of dimeric inhibins and activins reported previously and to suggest potential paracrine and endocrine roles for them. The results show that all the inhibin/activin subunit mRNAs are expressed in the testis of the chicken throughout the period of prepubertal development up to 18 weeks of age. However, in the ovary, only the betaA- and betaB-subunits were detected at all ages whereas the alpha-subunit mRNA could only be detected just before puberty. Quantification of the mRNA levels showed variation of each subunit with age. These temporal changes suggest relationship with paracrine functional role in the ovary or the testis. Quantitative changes in expression levels also suggests that there may be some relationship between mRNA levels and the type and amount of dimeric inhibins and activins produced at any developmental stage. There are major differences between the male and female gonads in the timing of the expression of different subunits. In conclusion, the expression of the mRNA subunits in the testis and ovary suggests that inhibins and activins are being produced but may be principally involved in autocrine/paracrine function within the gonads.
在雄性和雌性鸡青春期前发育阶段，血浆中几乎检测不到二聚体抑制素和激活素。这可能会被误解为表明这些蛋白质在性腺中不产生，且在此期间没有功能意义。实际上，很少有研究确定青春期前性腺中抑制素和激活素亚基的mRNA表达谱，以便确定它们在局部水平的分泌情况，并推测抑制素和激活素在这个发育阶段的潜在作用。在本研究中，测定了青春期前发育阶段鸡的卵巢和睾丸中α-、βA-和βB-亚基mRNA的表达。通过RT-PCR在3、5、6、8、10、12、16和18周龄时测定基因表达。在3、6、12和18周龄时通过竞争性RT-PCR对信使RNA水平进行定量，以检测其随发育的任何变化，提示其与先前报道的二聚体抑制素和激活素谱的潜在关系，并推测它们的潜在旁分泌和内分泌作用。结果表明，在青春期前发育至18周龄的整个阶段，鸡的睾丸中均表达所有抑制素/激活素亚基的mRNA。然而，在卵巢中，所有年龄均仅检测到βA-和βB-亚基，而α-亚基mRNA仅在青春期前才能检测到。mRNA水平的定量显示每个亚基随年龄变化。这些时间变化提示与卵巢或睾丸中的旁分泌功能作用有关。表达水平的定量变化还表明，mRNA水平与任何发育阶段产生的二聚体抑制素和激活素的类型和数量之间可能存在某种关系。不同亚基表达的时间在雄性和雌性性腺之间存在主要差异。总之，睾丸和卵巢中mRNA亚基的表达表明抑制素和激活素正在产生，但可能主要参与性腺内的自分泌/旁分泌功能。
