Expression of aromatase, estrogen receptor α and β, androgen receptor, and cytochrome P-450scc in the human early prepubertal testis

The expression of aromatase, estrogen receptor a (ER alpha) and beta (ER beta), androgen receptor (AR), and cytochrome P-450 side chain cleavage enzyme (cP450(scc)) was studied in prepubertal testis. Samples were divided in three age groups (GRs): GR1, newborns (1- to 21-d-old neonates, n = 5); GR2, postnatal activation stage (1- to 7-mo-old infants, n = 6); GR3, childhood (12- to 60-mo-old boys, n = 4). Absent or very poor detection of ER alpha by immunohistochemistry in all cells and by mRNA expression was observed. Leydig cells (LCs) of GR1 and GR2 showed strong immunostaining of aromatase and cP450(scc) but weak staining of ER beta and AR. Interstitial cells (ICs) and Sertoli cells (SCs) expressed ER beta, particularly in GR1 and GR2. Strong expression of AR was found in peritubular cells (PCs). For all markers, expression in GR3 was the weakest. In germ cells (GCs), i.e. gonocytes and spermatogonia, aromatase and ER beta were immunoexpressed strongly whereas no expression of ERa, AR, or cP450scc was detected. It is proposed that in newborn and infantile testis, testosterone acting on PCs might modulate infant LC differentiation, whereas the absence of AR in SCs prevents development of spermatogenesis. The role of estrogen is less clear, but it could modulate the preservation of an adequate pool of precursor LCs and GCs.