ABSTRACT
Glial cell line-derived neurotrophic factor (GDNF) and its receptors GFRalpha-1 and GFRalpha-2 were found in the human testis during fetal development (15-34 weeks of gestation) and in adult men (51-86 years of age) by means of RT-PCR, immunohistochemistry and Western blot techniques. Gene expression of GDNF could be established in the human testis and immunoreactivity (IR) for GDNF was detectable in Leydig cells, Sertoli cells, some spermatocytes and round spermatids as well as in smooth muscle cells of the wall of arterioles and small arteries. In the adult human testis, Sertoli and Leydig cells showed GFRalpha-1-IR, whereas GFRalpha-2-IR was located exclusively in Leydig cells. Different to man, in the rat GDNF-IR in Sertoli cells was detectable only until postnatal day10, providing evidence for species related variability in the expression of GDNF. These findings suggest a critical role for GDNF during the differentiation of testicular structures and provide evidence for an additional important function in the adult human and rodent testis.
Subject(s)
Drosophila Proteins , Nerve Growth Factors , Nerve Tissue Proteins/analysis , Proto-Oncogene Proteins/analysis , Receptor Protein-Tyrosine Kinases/analysis , Testis/chemistry , Aged , Aged, 80 and over , Animals , Blotting, Western , Gestational Age , Glial Cell Line-Derived Neurotrophic Factor , Glial Cell Line-Derived Neurotrophic Factor Receptors , Humans , Immunohistochemistry , Leydig Cells/chemistry , Male , Middle Aged , Muscle, Smooth, Vascular/chemistry , Nerve Tissue Proteins/genetics , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-ret , Rats , Receptor Protein-Tyrosine Kinases/genetics , Reverse Transcriptase Polymerase Chain Reaction , Sertoli Cells/chemistry , Spermatids/chemistry , Spermatozoa/chemistry , Testis/embryologyABSTRACT
The authors demonstrate for the first time the immunocytochemical expression of the low-affinity neurotrophic growth factor (NGF) receptor p75LNGFR and the high-affinity NGF receptor trkA in the human testis. Employing the polyclonal anti-p75LNGFR antibody and the polyclonal anti-trkA antibody they report strong immunoreactivity for those antigens in the interstitial Leydig cells. Sertoli cells and some cellular elements of the germinative epithelium were also trkA-positive. These findings implicate the neurotrophic factor NGF and its receptors p75LNGFR and trkA in the autocrine and paracrine regulation of the steroidogenic activity of Leydig cells of the human testis.
