title: Catecholamine-synthesizing enzymes in the adult and prenatal human testis.
abstract: Catecholamines play functional roles in the mature and developing mammalian testis but the cell types responsible for their local synthesis are still controversially discussed. Here, we demonstrate that four enzymes involved in the biosynthesis of catecholamines, namely, tyrosine hydroxylase (TH), aromatic amino acid decarboxylase (AADC), dopamine beta-hydroxylase (DBH) and phenylethanolamine- N-methyltransferase (PNMT), are expressed in Leydig cells of the human testis. Tyrosine hydroxylase, the key enzyme of the biosynthesis of catecholamines, was localized to Leydig cells both at the transcript level (by RT-PCR analyses and by in situ hybridization assays) and at the protein level (by immunoblotting and by immunohistochemistry). The other enzymes were also demonstrated in Leydig cells by RT-PCR and immunohistochemical analyses. The presence of TH, AADC, DBH, and PNMT in human Leydig cells was found, in addition, by immunohistochemical approaches carried out on sections from prenatal human testes. Thus, the present study identifies the Leydig cells as the presumed sites of catecholamine production in both the mature and fetal human testes and further supports the previously recognized neuroendocrine characteristics of this cell type.
authors.affiliation: Institute of Anatomy, University Hospital Hamburg, Martinistrasse 52, 20246 Hamburg, Germany. davidoff@uke.uni-hamburg.de
authors.forename: Michail S
authors.initials: MS
authors.lastname: Davidoff
authors.forename: Hendrik
authors.initials: H
authors.lastname: Ungefroren
authors.forename: Ralf
authors.initials: R
authors.lastname: Middendorff
authors.forename: Yvetta
authors.initials: Y
authors.lastname: Koeva
authors.forename: Mariana
authors.initials: M
authors.lastname: Bakalska
authors.forename: Nina
authors.initials: N
authors.lastname: Atanassova
authors.forename: Adolf F
authors.initials: AF
authors.lastname: Holstein
authors.forename: Davor
authors.initials: D
authors.lastname: Jezek
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Pusch
authors.forename: Dieter
authors.initials: D
authors.lastname: Müller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000378:metabolism*; D002395:Catecholamines / Q000096:biosynthesis*; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007985:Leydig Cells / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000196:embryology / Q000201:enzymology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase; D010625:Phenylethanolamine N-Methyltransferase; D001142:Aromatic-L-Amino-Acid Decarboxylases