Enables 3-oxo-5-alpha-steroid 4-dehydrogenase activity. Acts upstream of or within androgen biosynthetic process and male genitalia development. Predicted to be located in cell body fiber; cytoplasm; and neuronal cell body. Is expressed in genitourinary system. Human ortholog(s) of this gene implicated in hypospadias and prostate cancer. Orthologous to human SRD5A2 (steroid 5 alpha-reductase 2). [provided by Alliance of Genome Resources, Apr 2022]