Immunocytochemical expression of p75LNGFR and trkA in Leydig cells of the human testis.

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.