CONICET | Buscador de Institutos y Recursos Humanos

We have previously found expression of cyclooxygenase 2 (COX2), key enzyme in the biosynthesis of prostaglandins (PGs), in Leydig cells of infertile men whereas it is absent in normal human testes (Frungieri et al, Proc Natl Acad Sci USA, 99:15072, 2002). We have also described COX2 in reproductively active Syrian hamster Leydig cells but not in testes from other adult species (mice, rats, monkeys, pigs) (Frungieri et al, Endocrinology, 147:4476, 2006). The aims of this study were to investigate COX2 expression: 1) in hamster testes during sexual development, 2) in hamster testes after exposing adult animals to a short day photoperiod for 16 weeks (6h light/day) in order to reach maximum testicular regression, 3) in Leydig cells after treatment with testosterone (T) or prolactin (PRL). Pubertal and adult reproductively active hamsters that present high circulating levels of T and PRL, expressed COX2 in Leydig cells. Prepubertal and photoperiodically regressed adult hamsters with low serum concentrations of T and PRL did not express testicular COX2. The effect of T and PRL on COX2/PGs was evaluated by RT-PCR, Western blot and immunoassay. In active hamster Leydig cells and/or in the TM3 murine Leydig cell line, T and PRL stimulated mRNA and protein COX2 expression, as well as production of PGD2 and PGF2a that are known to regulate steroidogenesis (Frungieri et al, Endocrinology, 147:4476, 2006; Schell et al, Fertil Steril, 88:233, 2007). In conclusion, our results demonstrate that T and PRL induce COX2 and PGs in Leydig cells. Thus, hormonal environment might be crucial for the regulation of testicular PGs production at least during sexual development and photoperiodic variations in hamsters. Supported by UBA, CONICET, ANPCyT