The steroidal sulfonylpyrazole 1 bound to the rat ventral prostate androgen receptor in vitro; it inhibited testosterone propionate induced increases in ventral prostate weight in vivo in the castrated, immature male rat with an ED, of 15 mg/kg PO. Compound 1 lacked androgenic activity in vivo in contrast to the parent steroidal pyrazole 5, which was both androgenic and antiandrogenic. The 2'-and 5'-methylsulfonyl isomers 6 and 6a did not ...