Ultrastructure of the pineal cells of the homing pigeon Columba livia and magnetic fields (first trials).

The homing pigeon Columba livia was exposed to uniform 60 Hz AC magnetic fields, generated by Helmholtz coils with an intensity of 200 mG for 48 hrs. The microscopic studies performed revealed that only some of the pineal cells (between 20 and 30%) seemed to respond to the magnetic stimulation, and showed different ultrastructural morphological changes; the most striking effect was an apparent increase of apocrine secretion to the luminal spaces in the epiphyseal epithelium of this avian species.