Monts B S, Breyer P R, Rothrock J K, Pescovitz O H
Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis, IN.
Endocrine. 1996 Feb;4(1):73-8. doi: 10.1007/BF02738877.
Growth hormone-releasing hormone (GHRH) belongs to a family of peptides expressed at high levels in the brain and digestive system of mammals. We have identified GHRH mRNA and peptide in rat and human germ cells, and detected a GHRH receptor mRNA in Sertoli cells. GHRH treatment of cultured Sertoli cells results in accumulation of cAMP and increased expression ofc-fos and stem cell factor (SCF), two factors critical for normal germ cell development. The current study was designed to localize within testis the transcription of other members of the GHRH family, and their receptors, and to determine if they also stimulate SCF. RNAs from separated testicular cells were amplified by comparative reverse transcription-polymerase chain reaction (RT-PCR). Southern blot analysis of the PCR products verified the presence of five GHRH family peptide and receptor transcripts in distinct testicular cell types. Transcripts encoding VIP and glucagon, and the receptors for pituitary adenylate cyclase activating peptide (PACAP) and glucagon, were detected predominantly in Leydig cells. In contrast, expression of GHRH, PACAP, secretin, and secretin receptor predominated in germ cells. Receptors for GHRH and VIP were expressed equally in all testicular cell types. To determine if, like GHRH, any of these other peptides activate Sertoli cell expression of SCF, primary Sertoli cell cultures were treated for 4-6 h with 10 or 100 nM of each individual factor. There was no consistent stimulation of SCF mRNA by VIP, PACAP, glucagon, or secretin. Differential expression of these peptides and their receptors suggests that they may each have unique paracrine functions within the testis.
生长激素释放激素（GHRH）属于一类在哺乳动物大脑和消化系统中高表达的肽家族。我们已在大鼠和人类生殖细胞中鉴定出GHRH mRNA和肽，并在支持细胞中检测到GHRH受体mRNA。用GHRH处理培养的支持细胞会导致cAMP积累，并增加c-fos和干细胞因子（SCF）的表达，这两个因子对正常生殖细胞发育至关重要。本研究旨在确定GHRH家族其他成员及其受体在睾丸内的转录定位，并确定它们是否也刺激SCF。通过比较逆转录-聚合酶链反应（RT-PCR）扩增分离的睾丸细胞中的RNA。对PCR产物的Southern印迹分析证实了在不同的睾丸细胞类型中存在五种GHRH家族肽和受体转录本。编码血管活性肠肽（VIP）和胰高血糖素的转录本，以及垂体腺苷酸环化酶激活肽（PACAP）和胰高血糖素的受体，主要在睾丸间质细胞中检测到。相比之下，GHRH、PACAP、促胰液素和促胰液素受体的表达在生殖细胞中占主导地位。GHRH和VIP的受体在所有睾丸细胞类型中表达相同。为了确定这些其他肽是否像GHRH一样激活支持细胞中SCF的表达，将原代支持细胞培养物用每种单独因子的10或100 nM处理4-6小时。VIP、PACAP、胰高血糖素或促胰液素均未对SCF mRNA产生一致的刺激作用。这些肽及其受体的差异表达表明它们可能在睾丸内各自具有独特的旁分泌功能。
