Abstract
Luteinizing hormone‐releasing factor (LRF)‐like immunoreactivity was demonstrated by a three‐layer immunoperoxidase method in the islet cells of human pancreas and in the neoplastic cells of insulomas. Adenocarcinomas originating in the exocrine pancreas were LRF‐negative. The results demonstrate another hypothalamic peptide‐like material in the gastrointestinal tract, the biological role of which remains to be clarified.