Variation in human platelet 3H-imipramine binding.

Platelet 3H-imipramine binding values from 45 normal controls and 20 depressed subjects were collected over a 2-year period. During this time, wide inter-individual variations in the affinity constant (Kd) and maximal number of binding sites (Bmax) were observed in the control population; however, we failed to observe a seasonal change in platelet 3H-imipramine binding. The Kd and Bmax values of depressed subjects were not significantly different from those of controls.