To examine the production of steroids with potential oocyte maturation-inducing activity in the spotted flounder, Verasper variegatus, we have incubated post-vitellogenic oocytes (0.82­0.95mm in diameters) with radiolabeled pregnenolone and $17alpha-hydroxyprogesterone$. The resulting metabolites were analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The two main metabolites (progestogens) found in both incubations co-migrated with $17alpha-hydroxy$, $20alpha-dihydroprogesterone$ $(17alpha, 20alpha OHP)$ and $17alpha-hydroxy,;$20eta-dihydroprogesterone$ (17 a20{30HP). Additional chromatography by HPLC and TLC confirmed the presence of radioactive $17alpha, 20alpha OHP$ and a large amount of unknown metabolite. The present study did not reveal in vitro formation of $l7alpha 20eta OHP$. Although 1$l7alpha 20eta OHP$ was found in a small amount, the synthesis of this steroid suggests that it may play a role in regulating the oocyte maturation process in the spotted flounder.