Adrenoceptor and imipramine receptor binding during the menstrual cycle.

The binding characteristics of platelet alpha 2-adrenoceptors, lymphocyte beta 2-adrenoceptors and platelet imipramine receptors were studied in five women during their menstrual cycle. A significant cyclic variation in the number of beta 2-adrenoceptor sites on intact lymphocytes was found during the menstrual cycle, while binding to alpha 2-adrenoceptors and imipramine receptors remained unchanged.