title: Expression of beta-nerve growth factor and its receptor in rat seminiferous epithelium: specific function at the onset of meiosis.
abstract: beta-Nerve growth factor (NGF) is expressed in spermatogenic cells and has testosterone-downregulated low-affinity receptors on Sertoli cells suggesting a paracrine role in the regulation of spermatogenesis. An analysis of the stage-specific expression of NGF and its low affinity receptor during the cycle of the seminiferous epithelium in the rat revealed NGF mRNA and protein at all stages of the cycle. Tyrosine kinase receptor (trk) mRNA encoding an essential component of the high-affinity NGF receptor was also present at all stages. In contrast, expression of low affinity NGF receptor mRNA was only found in stages VIIcd and VIII of the cycle, the sites of onset of meiosis. The low-affinity NGF receptor protein was present in the plasma membrane of the apical Sertoli cell processes as well as in the basal plasma membrane of these cells at stages VIIcd to XI. NGF was shown to stimulate in vitro DNA synthesis of seminiferous tubule segments with preleptotene spermatocytes at the onset of meiosis while other segments remained nonresponsive. We conclude that NGF is a meiotic growth factor that acts through Sertoli cells.
authors.affiliation: Department of Anatomy, University of Turku, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Parvinen
authors.forename: M
authors.initials: M
authors.lastname: Pelto-Huikko
authors.forename: O
authors.initials: O
authors.lastname: Söder
authors.forename: R
authors.initials: R
authors.lastname: Schultz
authors.forename: A
authors.initials: A
authors.lastname: Kaipia
authors.forename: P
authors.initials: P
authors.lastname: Mali
authors.forename: J
authors.initials: J
authors.lastname: Toppari
authors.forename: H
authors.initials: H
authors.lastname: Hakovirta
authors.forename: P
authors.initials: P
authors.lastname: Lönnerberg
authors.forename: E M
authors.initials: EM
authors.lastname: Ritzén
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000737:chemistry; D016764:Cell Polarity; D004247:DNA / Q000096:biosynthesis; D007150:Immunohistochemistry; D008297:Male; D008540:Meiosis / Q000502:physiology*; D016253:Microscopy, Immunoelectron; D009414:Nerve Growth Factors / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D017475:Receptors, Nerve Growth Factor; D012670:Seminiferous Epithelium / Q000378:metabolism*; D012708:Sertoli Cells / Q000378:metabolism; D013090:Spermatocytes / Q000378:metabolism; D013091:Spermatogenesis / Q000502:physiology
chemical_list: D009414:Nerve Growth Factors; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017475:Receptors, Nerve Growth Factor; D004247:DNA