Effects of illicit growth promoters upon steroidogenic enzyme gene expression profiles in cattle testis.

Recently, the effect of illicit growth promoters (GPs) upon cattle transcriptome have excited increasing interest within the scientific community. In the present study, pre-transcriptional effects of three illicit protocols upon most of cattle steroidogenic enzymes were investigated. Beef cattle were administered with: (A), dexamethasone, given either orally (DOS) or intramuscularly (DIM); (B), dexamethasone, alone (DOSS) or together with 17β-oestradiol (DOE); (C), dehydroepiandrosterone (DHEA) and 1,4-androstadiene-3,17-dione (ADD), orally administered either alone (DHEA, ADD) or in association (DHAD). The effect upon eight testicular steroidogenic enzymes and four nuclear receptors were measured by a quantitative Real Time RT-PCR approach. Significant (p<0.05, p<0.01), albeit not univocal, results were obtained. A GP-dependent effect was observed upon P450c17 and the mineralcorticoid-like receptor gene (experiment A, DIM group); P450c17, 3-HSD and 3-HSD, 17-HSD , estrogen receptor alpha (experiment B, DOSS and DOE, respectively); P450 aromatase, P450scc, 3-HSD and the androgen receptor gene (experiment C, DHEA and DHAD, respectively). Present results suggest that different GPs schedules are likely to affect most of genes involved in gonadal steroid synthesis. Consequently, testis might be hypothetically considered as a potential surrogate tissue, whose usefulness in the screening of GPs abuse has to be investigated more in depth.