Oestrogen and progesterone change the binding characteristics of alpha-adrenergic and serotonin receptors on rabbit platelets.
The binding characteristics of the alpha-adrenergic and serotonin receptors on intact rabbit platelets were identified using [3H]-dihydroergocryptine and [3H]-5-hydroxytryptamine respectively. In untreated female rabbits a single slpha-adrenoceptor and two serotonin receptors were identified with ligand affinities similar to those in human platelets. The effects of oestrogen and/or progesterone on the alpha-adrenergic and serotonin receptors of rabbit platelets were studied. Oestrogen alone increased the capacity of serotonin receptors but reduced that of the alpha-adrenoceptor. Oestrogen plus progesterone reduced the capacity of both receptors and reduced the affinity of the alpha-adrenoceptor. The possible mechanisms of the steroid-induced changes and the implications of these with regard to the effects of the oral contraceptive pill are discussed.
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D011374:Progesterone / Q000494:pharmacology*; D011817:Rabbits; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*
D004967:Estrogens; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D011985:Receptors, Serotonin; D011374:Progesterone; D004958:Estradiol