Abstract: The two enzymes 3β-hydroxysteroid dehydrogenase (3βHSDs) and 17β-hydroxysteroid dehydrogenase(17βHSDs) are essential for the conversion of all steroid hormones from non-active to their active forms,which play an important role in regulating the balance between hormones and maintaining the normal physiological functions in mammals. Here we presented 3βHSDs and 17βHSDs gene molecular structure and function,tissu-specific expression,as well as regulation of transcription. Moreover,the relation of these two enzymes in pig production was also reviewed.

Key words: 3β-hydroxysteroid dehydrogenase; 17β-hydroxysteroid dehydrogenase; gene structure; transcription regulation