Middendorff R, Müller D, Paust H J, Davidoff M S, Mukhopadhyay A K
Institute of Anatomy, University of 20246 Hamburg, Germany.
J Clin Endocrinol Metab. 1996 Dec;81(12):4324-8. doi: 10.1210/jcem.81.12.8954035.
Functional studies indicate that natriuretic peptides have direct effects on Leydig cells of the testis. In this report, we demonstrate local synthesis of one member of the natriuretic peptide family, C-type natriuretic peptide (CNP), in Leydig cells of human testes. Using RT-PCR assays, messenger RNA (mRNA) for the CNP precursor was detected in human testis and found to be prominently expressed in Leydig cells. Immunohistochemical analyses revealed CNP to be almost exclusively associated with Leydig cells. Distinct differences in the staining intensity-including cells without detectable staining-suggest a heterogeneity of CNP expression within the Leydig cells. Moreover, the presence of transcripts for the CNP receptor, a particulate guanylate cyclase, termed GC-B, was demonstrated by RT-PCR in human testis and in isolated Leydig cells. The expression of this receptor in human testis membranes could be confirmed by affinity labeling with 125I-labeled CNP. These findings demonstrate, for the first time, the production of a natriuretic peptide in human Leydig cells. The occurrence of CNP and its receptor in the human testis points to a local role of the peptide, presumably acting in an auto- or paracrine manner to modulate organ-specific functions.
功能研究表明，利钠肽对睾丸的间质细胞有直接作用。在本报告中，我们证明了利钠肽家族的一个成员——C型利钠肽（CNP）在人类睾丸间质细胞中的局部合成。使用逆转录聚合酶链反应（RT-PCR）分析，在人类睾丸中检测到CNP前体的信使核糖核酸（mRNA），并发现其在间质细胞中显著表达。免疫组织化学分析显示，CNP几乎只与间质细胞相关。染色强度存在明显差异，包括未检测到染色的细胞，这表明间质细胞内CNP表达存在异质性。此外，通过RT-PCR在人类睾丸和分离的间质细胞中证实了CNP受体（一种称为GC-B的颗粒型鸟苷酸环化酶）转录本的存在。用125I标记的CNP进行亲和标记可证实该受体在人类睾丸膜中的表达。这些发现首次证明了人类间质细胞中利钠肽的产生。CNP及其受体在人类睾丸中的存在表明该肽具有局部作用，可能以自分泌或旁分泌方式调节器官特异性功能。
