Chimeric polypeptides comprising a dihydrotestosterone (DHT) reductase moiety, such as 3 alpha-hydroxysteroid dehydrogenase (3α-HSD), fused to a signal peptide moiety, polynucleotides encoding same, and compositions comprising at least one microorganism cell capable of secreting the chimeric polypeptide, are provided. Further provided are methods and kits for treating, preventing or ameliorating androgen-dependent disorders, including but not limited to androgenic alopecia.