Platelet 3H-imipramine binding and steroid hormones serum concentrations during the menstrual cycle

The presence of high affinity binding sites for 3H-imipramine (3H-IMI) in human platelets is by now well established. This recognition site is associated with the transporter for 5HT, and may be a biological marker in depression. Fluctuations of other putative biological markers of depression (i.e. platelet MAO activity) have been demonstrated and shown to be correlated with variations in steroid hormones. Therefore, the KD and Bmax of 3H-IMI binding was determined in platelets of young women during the menstrual cycle. Our results indicate that within the limits of intraindividual variations, neither the KD or the Bmax of 3H-IMI binding in platelets is significantly modified during the menstrual cycle.