Interference of gestagens and androgens with rat uterine oestrogen receptors.
The inhibitory effect of some gestagens and calusterone on the binding of oestradiol-17beta to its specific uterine receptors has been investigated in intact rats. Progesterone, medrogestone, clogestone, medroxyprogesterone acetate and calusterone reduce the specific oestradiol-receptor interaction in vitro; this effect is dose-dependent and does not differ significantly from one drug to the other. A more relevant decrease in the amount of oestradiol-17beta bound to specific receptors has been observed with calusterone. Progesterone, clogestone, medrogestone, medroxyprogesterone acetate and calusterone given orally induce a marked decrease (between 30 and 70% depending on the dose) in the binding capacity of oestradiol-17beta to specific uterine receptors in vivo. Results from a Scatchard plot analysis suggest that the interference with the binding of oestradiol-17beta caused by both progestogens and calusterone is due to a non-competitive interaction.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D008524:Medrogestone / Q000494:pharmacology; D008525:Medroxyprogesterone / Q000494:pharmacology; D008777:Methyltestosterone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D011244:Pregnadienediols / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D011960:Receptors, Estrogen / Q000187:drug effects* / Q000378:metabolism; D014599:Uterus / Q000187:drug effects / Q000378:metabolism*
D011244:Pregnadienediols; D011960:Receptors, Estrogen; D008524:Medrogestone; D011374:Progesterone; D004958:Estradiol; D008525:Medroxyprogesterone; D008777:Methyltestosterone