[Immunocytochemical characterization of enteric hormones (author's transl)]

As yet 16 different polypeptide have been found in the gastrointestinal tract. Definite entero-endocrine cell types classified mainly by ultrastructural features were identified--more or less reliable--as the cellular sources of certain enteric hormones. Concerning the immunocytochemical characterization of enteric hormones and the identification of entero-endocrine cells responsible for the synthesis of enteric hormones, however, several peculiarities have to be taken into consideration. These included similarities certain enteric hormones on the one hand and similarities in the ultrastructure of entero-endocrine cell type on the other as well as peculiarities with respect to immunoreactivities of entero-endocrine cells (e.g. the ability of certain entero-endocrine cell types to bind immunoglobulins unspecifically). Apart from the immunocytochemical identification of entero-endocrine cells at the ultrastructural level further investigations in this field should deal with the immunocytochemical localization of hormone precursor substances. Thus the multitude of enteric hormones and entero-endocrine cell types may be reduced to some "basic" types. Finally, investigations on enteric polypeptide hormones seem to be a wider interest in biology and medicine since some of these hormones are also located in the central and peripheral nervous system. These peptides may represent a system of chemical messengers utilized in the body as hormones, neurotransmitters and paracrine (i.e. local acting) substances.