Molecular cloning and regulation of porcine SULT2A1: relationship between SULT2A1 expression and sulfoconjugation of androstenone

Abstract

Hydroxysteroid sulfotransferase (SULT2A1) is a key enzyme in the testicular and hepatic metabolism of 5α-androstenone, which is a major component of the off-odor and off-flavor in pork known as boar taint. The goals of this study were to determine the role of testicular and hepatic SULT2A1 activity on plasma 5α-androstenone sulfate levels, the accumulation of 5α-androstenone in adipose tissue, and to gain insight into the regulatory control of SULT2A1. Testicular SULT2A1 activity was negatively correlated (r= −0.57; P<0.01) with 5α-androstenone concentrations in fat. The differences observed in SULT2A1 activity warranted investigation into potential genetic variation within porcine SULT2A1. The cDNA sequence of porcine Sult2A1 was determined to be >82% homologous to the human, mouse, and rat Sult2A1 genes. A single nucleotide polymorphism was detected within the coding region of the Sult2A1 from individual testes and liver samples; however, this did not affect the amino acid sequence of the enzyme. Western blot analysis determined that animals with high concentrations of 5α-androstenone in fat and low SULT2A1 activity had corresponding low levels of SULT2A1 protein compared with animals with low levels of 5α-androstenone in fat. Real-time PCR analysis indicated that Sult2A1 mRNA was increased 2.8-fold in animals with high levels of the protein relative to animals with low levels of the protein. Furthermore, we demonstrated the positive role of the nuclear receptors constitutive androstane receptor and pregnane X receptor, as well as the possible role of farnesoid X receptor in the regulation of testicular SULT2A1 activity. Together, the results of this study suggest that differences in SULT2A1 expression can influence 5α-androstenone accumulation in fat.