Use of HPLC to determine the effect of 17 beta-hydroxy-7 alpha-methylandrost-5-en-3-one (RMI 12,936) on production of progesterone by rat ovarian homogenate.

A new high presure liquid chromatography (HPLC) method for the determination of progesterone in the presence of other delta 43-ketosteroids is described. Using this method it is shown that the rate of production of progesterone from pregn-5-ene-3,20-dione by rat ovarioan homogenate is initally rapid but falls to zero within 10 min. Experiments indicate that the inhibition is due to the progesterone formed. Inclusion of RMI 12,936 with the pregn-5-ene-3,20-dione substrate results in a lower final level of progesterone and continuous production of 7 alpha-methyltestosterone. The reduction in the levels of progesterone in presence of RMI 12,936 corresponds closely to the reduction in plasma progesterone in vivo folowing administration of RMI 12,936 described previously.