[Distribution of the enterochromaffin ("EC") cells and those of the "APUD" series in the gastrointestinal tract of the calf].

Based on morphological and histochemical data, the Authors describe the distribution of "EC" (5-HT-producing) and of the other endocrine cells of the "APUD" series (polypeptide hormone-producing) in the gastro intestinal tract of weaned and unweaned 3-4 month old calves. The results demonstrate that: -- no difference concerning the different diet can be correlated; -- no endocrine cell is present in the vorestomachs; -- the "EC" cells in the abomasum prevail in the fundus glands; they are demonstrable also in every tract of the intestine and are more numerous in the duodenum and in the rectum; -- within the "APUD" series four cellular types are demonstrable in the abomasum; two are in the cardias, one in the fundus and one in the pylorus glands; the last one probably corresponds to the gastrin-producing "G" cells. -- In the small intestine, particularly numerous in the duodenum, a probably heterogeneous family of endocrine cells is present, while in the coecum, in the colon and, above all, in the rectum, cells probably corresponding to "EG" cells are identifiable. These results are compared to those previously obtained in the adult Cattle: remarkable differences are demonstrable only within "APUD" cells of abomasum.