Postnatal development of intestinal endocrine cell populations in the water buffalo

The frequency and distribution of 11 endocrine cell populations were studie d in the intestine of differently aged buffalo, grouped on the basis of die t: 2-d-olds (suckling), 5-mo-olds (weaning) and 5-y-olds (ruminant adult di et). The endocrine cell populations were identified immunocytochemically us ing antisera against 5-hydroxytryptamine (5-HT), somatostatin, gastrin, cho lecystokinin (CCK), COOH-terminal octapeptide of gastrin/CCK, neurotensin, motilin, gastric inhibitory polypeptide (GIP), secretin, glucagon/glicentin (GLU/GLI) and polypeptide YY (PYY). In adult buffalos the regional distrib ution of endocrine cells is similar to that of other adult ruminants. Durin g postnatal development, these cell types showed the following changes in t heir frequency and distribution: (1) 5-MT, neurotensin and gastrin/CCK immu noreactive cells (i.c.) showed a decrease in frequency with age; (2) somato statin i.c. frequency remained stable with age; (3) motilin, GIP, secretin and CCK i.c. showed a slight increase in frequency with age; (4) GLU/GLI an d PYY i.c. decreased in frequency with age in the small intestine, caecum a nd proximal colon and an increase in frequency in the rectum. It was hypoth esised that the endocrine cell types, whose presence and localisation is su bstantially stable in all examined ages, probably contain substances that a re strictly necessary for intestinal function. In contrast the hormones con tained in the cell populations that decreased with age, are probably involv ed in physiological needs during the milk and weaning diet or play a role i n intestinal growth.