title: Differential expression of urocortin in human testicular germ cells in course of spermatogenesis: role for urocortin in male fertility?
abstract: OBJECTIVE
  To provide the first insights into the potential role of urocortin in mammalian spermatogenesis, we studied the expression of urocortin and corticotropin-releasing factor receptors 1 and 2 in the human testis. Urocortin is a bioactive peptide with antiapoptotic and antiproliferative properties. The proper regulation of apoptosis and proliferation is of high physiologic relevance in the control of spermatogenesis in adulthood and of the noncycling stage of gonocytes in fetal life.
  
  
  METHODS
  Using polymerase chain reaction analysis and immunohistochemistry, the expression and tissue localization of urocortin on mRNA and at the peptide level was studied in 9 normal adult, 5 fetal, and 5 Sertoli cell-only testicular specimens. Tissue localization of corticotropin-releasing factor receptors in normal adults was considered using immunohistochemistry.
  
  
  RESULTS
  We found that urocortin mRNA was present in all adult specimens tested and that the urocortin peptide was expressed in elongating spermatids, mature spermatozoa, and peritubular myoid cells, and to a lesser extent in Leydig cells. Corticotropin-releasing factor receptor 1 was mainly expressed in spermatogonia, spermatocytes, and Leydig cells, and corticotropin-releasing factor receptor 2 was mostly expressed in spermatogonia. The antibodies against urocortin produced a nuclear staining in fetal gonocytes. No significant immunopositivity for urocortin could be observed in the Sertoli cell-only specimens.
  
  
  CONCLUSIONS
  The expression of urocortin in normal adult and fetal testicular germ cells in the cell division arrest phases suggests a probable role for this peptide in the pathophysiology of germ cell differentiation and division. In human germ cells, the separate location of urocortin and its receptors indicates a receptor-independent action of urocortin in the course of spermatogenesis.
authors.affiliation: Department of Urology and Urological Oncology, Medizinische Hochschule Hannover, Hannover, Germany. tezval.hossein@mh-hannover.de
authors.forename: Hossein
authors.initials: H
authors.lastname: Tezval
authors.forename: Axel S
authors.initials: AS
authors.lastname: Merseburger
authors.forename: Jürgen
authors.initials: J
authors.lastname: Serth
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Herrmann
authors.forename: Jan U
authors.initials: JU
authors.lastname: Becker
authors.forename: Olaf
authors.initials: O
authors.lastname: Jahn
authors.forename: Markus A
authors.initials: MA
authors.lastname: Kuczyk
mesh_terms: D000328:Adult; D005298:Fertility; D006801:Humans; D008297:Male; D013091:Spermatogenesis; D013094:Spermatozoa / Q000378:metabolism*; D054832:Urocortins / Q000096:biosynthesis* / Q000502:physiology*
chemical_list: D054832:Urocortins