Laboratory of Animal Reproduction and Physiology, Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga, Shizuoka-City, Shizuoka 422-8529, Japan.
J Endocrinol. 2010 Nov;207(2):135-49. doi: 10.1677/JOE-10-0149. Epub 2010 Aug 31.
Although the physiological role of relaxin (RLN) in males remains largely unknown, there is limited evidence that the testis might be a candidate source and target of RLN in boars, as RLN transcripts are detected in the boar testis and it contains RLN-binding sites. To determine whether the boar testis acts as a source and target tissue of RLN, we characterised the expression pattern and cellular localisation of both RLN and its own receptor LGR7 (RXFP1) in boar testes during postnatal development by molecular and immunological approaches. Testes were collected from Duroc boars, and partial cDNA sequences of the boar homologue of human RXFP1 were identified. RLN expression increased through puberty onwards, while RXFP1 expression changed little during development. RLN mRNA and protein expression were restricted to the Leydig cells, whereas both Leydig cells and seminiferous epithelial cells expressed RXFP1 mRNA and protein. Interestingly, RLN was expressed in the testis as an 18 kDa form (the expected size of proRLN), but not as the 6 kDa mature form, during development because of a lack of the enzyme required for proRLN processing. In contrast, RXFP1 was detected at all stages as specific bands of 75 and 91-95 kDa (likely non-glycosylated and glycosylated RXFP1 respectively). Thus, we provide evidence for expression of RLN-RXFP1 ligand-receptor system in the boar testis, suggesting that the testis act as a source and possible target tissue of RLN.
虽然松弛素（RLN）在男性中的生理作用在很大程度上尚不清楚，但有限的证据表明，睾丸可能是公猪 RLN 的候选来源和靶标，因为在公猪睾丸中检测到 RLN 转录本，并且它含有 RLN 结合位点。为了确定公猪睾丸是否是 RLN 的来源和靶组织，我们通过分子和免疫方法研究了 RLN 及其自身受体 LGR7（RXFP1）在公猪睾丸发育过程中的表达模式和细胞定位。从杜洛克公猪中收集睾丸，并鉴定了人 RXFP1 同源物的猪 cDNA 序列。RLN 的表达在青春期后增加，而 RXFP1 的表达在发育过程中变化不大。RLN mRNA 和蛋白表达仅限于 Leydig 细胞，而 Leydig 细胞和生精上皮细胞均表达 RXFP1 mRNA 和蛋白。有趣的是，RLN 在睾丸中以 18 kDa 形式（预期的 proRLN 大小）表达，而不是以 6 kDa 成熟形式表达，因为缺乏用于 proRLN 加工的酶。相比之下，RXFP1 在所有阶段均以 75 和 91-95 kDa 的特异性条带检测到（可能分别是非糖基化和糖基化的 RXFP1）。因此，我们为 RLN-RXFP1 配体-受体系统在公猪睾丸中的表达提供了证据，表明睾丸是 RLN 的来源和可能的靶组织。
