Expression of the aromatase gene in the human prepubertal testis

It has been proposed that estrogens might play a negative feedback role in the local regulation of androgen biosynthesis in the testis. Although aromatase has been reported to be present in human adult Leydig cells, CYP19 gene expression in the human prepubertal testis has not been studied. Human prepubertal testicular tissue was obtained from 12 testes collected at necropsy. Ages ranged from 0.07 to 7 years, but 7 of the 12 subjects were younger than 3 months old. Tissue mRNA was subjected to RT-PCR analysis by two methods. Cytochrome P450arom mRNA was detected by non-radioactive RT-PCR in five of the 12 prepubertal testes collected from 0.05-7 year-old subjects, and in one testis collected from a 15 year-old pubertal control. Four of these five prepubertal samples belonged to the youngest infant group. Using a more sensitive, radioactive RT-PCR, aromatase mRNA was detected in all prepubertal testes. This study shows that the CYP19 gene is expressed in the prepubertal human testis including the period of early postnatal activation. It is possible that estrogens may have a role in prepubertal males during this period.