Gene expression of 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase in relation to androstenone, testosterone, and estrone sulphate in gonadally intact male and castrated pigs

Androstenone is one of the main compound responsible for boar taint, and 3 beta- hydroxysteroid dehydrogenase ( 3 beta HSD) might be involved in its metabolism. In this study, the gene expression of 3 beta HSD and 17 beta- hydroxysteroid dehydrogenase ( 17 beta HSD) were determined by real- time PCR analysis and related to the concentrations of androstenone, testosterone, and estrone sulphate ( E1S). The experiments were performed on gonadally intact male pigs classified based on high or low fat androstenone concentrations, as predetermined by HPLC, as well as on immunocastrated and surgically castrated male pigs. The male pigs with high androstenone concentrations in fat had low 3 beta HSD gene expression in liver and testis. Moreover, the 17 beta HSD gene expression in liver, but not in testis, varied negatively with fat androstenone concentrations. Immunocastrated and surgically castrated male pigs had nondetectable concentrations of fat androstenone and plasma testosterone and E1S, and the castration procedure induced a significant increase of 3 beta HSD and 17 beta HSD gene expression. The mRNA expression was generally much greater from the 3 beta HSD than from the 17 beta HSD gene. Furthermore, fat androstenone was negatively correlated with liver 3 beta HSD gene expression ( Pearson correlation, r = - 0.69; P < 0.05), and the 17 beta HSD gene expression in liver was negatively correlated with plasma E1S ( r = - 0.95; P < 0.001), indicating an important role of liver 17 beta HSD in the estrogen metabolism of gonadally intact male pigs. Another strong correlation was found between 3 beta HSD and 17 beta HSD gene expression in liver of the gonadally intact male pigs ( r = 0.86; P < 0.01), possibly reflecting similar regulation mechanisms of these genes.