Do catecholestrogens interact with the in vitro binding of radioligands to catecholamine receptors?
Using a competitive binding assay the effects of 2-hydroxyestradiol-17 beta, 4-hydroxyestradiol-17 beta, estradiol-17 beta and progesterone on the binding of tritiated catecholaminergic ligands to membrane preparations from rat brain and pituitary gland were studied. Up to a concentration of 10(-5) M none of the steroids tested was able to displace [3H]spiroperidol, [3H]dihydroergocryptine or [3H]dihydroalprenolol. The data suggest that the catecholestrogens do not interfere directly with the binding of catecholaminergic ligands to dopaminergic, alpha-adrenergic or beta-adrenergic receptors in the central nervous system. The view that a catechol structure is not essential for the interaction with dopaminergic receptors was further supported by the results obtained from additional studies on the competition of O-methylated and deaminated dopamine metabolites with [3H]spiroperidol binding.
D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D004082:Dihydroalprenolol / Q000378:metabolism; D004088:Dihydroergotoxine / Q000378:metabolism; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D002393:Estrogens, Catechol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D010902:Pituitary Gland / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000378:metabolism*; D017983:Receptors, Catecholamine; D013134:Spiperone / Q000378:metabolism; D013329:Structure-Activity Relationship
D002393:Estrogens, Catechol; D011941:Receptors, Adrenergic; D017983:Receptors, Catecholamine; D004088:Dihydroergotoxine; D004958:Estradiol; D013134:Spiperone; D004082:Dihydroalprenolol; C001390:2-hydroxyestradiol; C014036:4-hydroxyestradiol