title: Serum and placenta levels of ethynylestradiol in presence of ethynodiol diacetate after oral administration.
abstract: The ethynylestradiol concentration--in the presence of ethynodiol diacetate--in serum after oral administration was measured by a rapid radioimmunoassay method developed by the authors. It was found that the peak level was reached 1 h after administration, and even after 12 h a significant amount of free ethynylestradiol was present in the serum. The transfer of ethynylestradiol into the placenta was also studied in subjects who were 10-12 weeks pregnant. Placenta/serum quotients were calculated for the ethynylestradiol, and were found to increase in parallel with the dose of the drug administered, proving that an ethynylestradiol enrichment of the placenta occurred as early as 10-12 weeks of pregnancy.
mesh_terms: D000284:Administration, Oral; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000097:blood; D004997:Ethinyl Estradiol / Q000032:analysis* / Q000097:blood; D005040:Ethynodiol Diacetate / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D010920:Placenta / Q000032:analysis*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011863:Radioimmunoassay; D013997:Time Factors
chemical_list: D004997:Ethinyl Estradiol; D004958:Estradiol; D005040:Ethynodiol Diacetate