TRYPTAMINE OR TRYPTOPHYL PEPTIDES IN ENDOCRINE CELLS OF THE MAMMALIAN ADENOHYPOPHYSIS

In all species studied certain endocrine cells of the adenohypophysis exhibited intense fluorescence after treatment with formaldehyde-ozone but only weak fluorescence after treatment with formaldehyde alone. This is characteristic of both tryptamine and peptides with NH 2 -terminal tryptophan in protein droplet models. Excitation and emission maxima of the fluorophore in the pituitary were very similar to those of authentic tryptamine or tryptophyl peptide fluorophores. However, chemical analysis failed to demonstrate tryptamine in extracts of the pituitary, whereas large amounts of peptides with NH 2 -terminal tryptophan could be isolated and identified by fluorometry and thin layer chromatography. It is therefore suggested that the formaldehyde-ozone-induced fluorescence in the endocrine cells reflects the presence of tryptophyl peptides rather than tryptamine.