The paraganglia, a persisting endocrine system in man.

The paraganglia have been traced in surgical samples of para-aortic and pelvic retroperitoneal tissues using the formal-dehyde-induced fluorescence method for catecholamines. Clusters of catecholamine-storing cells were found in all (12) patients studied. Microspectrofluorometric recordings showed high amounts of catecholamine in the well-vascularized cell groups. A large proportion of the paraganglia, which are most prominent during the fetal period, also persist during postnatal life.