AROMATIZATION AND HYDROLYSIS OF NORETHISTERONE-3-OXIME IN RABBIT

Two pharmacologically active metabolites, norethisterone (NET) and eth inylestradiol (EE(2)), were detected by HPLC and HPLC-RIA methods in r abbit plasma following single i.v. and i.g. administration at a dose o f 1 mg/20 mu Ci/kg of [H-3]norethisterone-3-oxime (NETO). Approximatel y 48% (i.v. injection) and 91% (i.g. administration) of the NETO dose were hydrolyzed to NET. Although only 0.35% of the NETO dose was aroma tized to EE(2), due to its high estrogenic potency, EE, might contribu te to the overall pharmacological pattern of NETO in the rabbit.