HISTOCHEMICAL STUDIES ON METABOLISM OF L-DOPA AND SOME RELATED SUBSTANCES IN EXOCRINE PANCREAS

The turnover of L‐DOPA and some related substances was studied with the fluorescence method of Falck and Hillarp. All the amino acids injected were easily taken up by the pancreas. This, however, was not the case with the corresponding amines. Only after L‐DOPA and DA administration, fluorescent granules could be seen in the apical zones of the exocrine cells. These granules were found to be identical with the zymogen granules. Decarboxylase inhibition prevented and MAO and COMT inhibition prolonged the appearance of the fluorescent granules. This indicates, that the fluorescent products stored in the zymogen granules is dopamine rather than DOPA. © 1969 Scandinavian Physiological Society