Steroidogenic enzyme gene expression profiles in the testis of cattle treated with illicit growth promoters.

Recently, the effect of illicit growth promoters (GPs) upon the cattle transcriptome has drawn the increasing attention of the scientific community. In the present study, the pre-transcriptional effects of three different illicit protocols on a set of target genes, including steroidogenic enzymes and three related transcription factors, were estimated in cattle testis. Beef cattle were administered with dexamethasone (DEX) orally (group D(1)) or intramuscularly in experiment 1 (group DIM). In experiment 2, DEX was orally administered alone (group D(2)) or with 17β-estradiol (group DE), and in experiment 3, dehydroepiandrosterone and boldione were orally administered alone (group DHEA and group ADD) or in combination (group DHAD). The GP effects were measured by quantitative real time RT-PCR. The results of our study were significant but not univocal. A GP-dependent effect on target gene mRNA levels was noticed for 3β-hydroxysteroid dehydrogenase type 1 (HSD3β1,p<0.05 and p<0.01 for the D(2), DE and DHAD groups, respectively), the cytochrome P450 side chain cleavage (DHAD, p<0.05), the cytochrome P450 17A1 (DIM and D(2), p<0.05), HSD17β3 (DE, p<0.05), aromatase (DHEA, p<0.05), the androgen receptor (DHAD, p<0.05) and the mineralocorticoid receptor-like (DIM, p<0.05). Our present results suggest that different GP schedules are likely to affect genes involved in steroid synthesis and regulation in cattle testis. Thus, this tissue might be considered a potential surrogate tissue that warrants further study into its usefulness in the screening of GP abuse.