Receptor binding of allylestrenol, a progestagen of the 19-nortestosterone series without androgenic properties

• Published in: Journal of steroid biochemistry Vol. 23; no. 2; pp. 165 - 168
• Main Authors: Bergink, E.W., Loonen, P.B.A., Kloosterboer, H.J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.08.1985; New York, NY Pergamon
• Subjects: Allylestrenol - metabolism; Animals; Binding, Competitive; Biological and medical sciences; Breast Neoplasms; Carrier Proteins - metabolism; Cell Line; Estrenes - metabolism; Female; Hormones. Endocrine system; Humans; Kinetics; Medical sciences; Myometrium - metabolism; Pharmacology. Drug treatments; Rabbits; Receptors, Androgen - metabolism; Receptors, Estrogen - metabolism; Receptors, Glucocorticoid - metabolism; Receptors, Progesterone - metabolism; Receptors, Steroid - metabolism; Sex Hormone-Binding Globulin; Biological fixation; Synthetic product; Allylestrenol; Metabolite; Analog; Nandrolone; Sex steroid hormone; Progestagen; Hormonal receptor
• ISSN: 0022-4731
• DOI: 10.1016/0022-4731(85)90232-8

Allylestrenol (17α-allyl-17β-hydroxy-4-estren) is an orally active progestagen of the 19-nortestosterone series resembling progesterone since it has no detectable androgenic activity in animal studies and in the human. In the present study, the affinity of its 3-keto metabolite for the transformed progesterone receptor in intact MCF-7 cells was about twice that of progesterone and cyproterone acetate and about 2–3 times less than that of medroxyprogesterone acetate and norethisterone, reflecting the known progestational activity of allylestrenol. The affinity of 3-ketoallylestrenol for the transformed androgen receptor in intact MCF-7 cells was weak (like other progestagens lacking androgenic activity or possessing anti-androgenic activity) and lower than that of weakly androgenic progestagens. On the other hand, the relatively high affinity of 3-keto-allylestrenol for the non-transformed androgen receptor at 4°C in the cytosol fraction did not reflect the known lack of androgenic activity of allylestrenol. Thus competitive studies carried out with transformed receptor complexes in intact cells at 37°C and non-transformed complexes in cytosol distinguish progestagen with weak androgenic activity (e.g. norethisterone) from those displaying no androgenic activity or possessing anti-androgenic activity (e.g. 3-keto-allylestrenol, progesterone, cyproterone acetate and spironolactone).