Development of pancreatic endocrine cells in the rat fetus.

Abstract

Summary. Prenatal development of rat pancreatic endocrine cells was investigated by the immunoperoxidase technique and the following results were obtained: 1) Glucagon immunoreactive cells are the first endocrine element of the pancreas appearing already on day 11 of gestation, when the dorsal pancreatic bud is still quite small and the ventral pancreatic primordium is hardly swollen out.Most of the glucagon reactive cells are located in the epithelium of the foregut and the dorsal pancreatic bud but a few of them are attached to the base of the epithelium from the outside.2) Insulin and pancreatic polypeptide (PP) immunoreactive cells are first demonstrable in small cell clusters budding from the exocrine tubules on day 14, whereas somatostatin and gastrin reactive cells on day 17 and 18, respectively.These findings support the hypothesis that the majority of pancreatic endocrine cells is derived from the epithelium of the foregut.3) PP reactive cells, appearing first on day 14, assume gradually a peripheral position in the growing islet of Langerhans. Immediately before birth they attain the population and flattened cell shape comparable to those in the adult pancreas. Their counterpart in the duodenum is found as open type basal-granulated cells in the rat fetus. 4) Noteworthily, glucagon-like immunoreactivity is found in some neuron-like cells of the Auerbach's plexus between the muscle layers of the duodenum on day 19.

Growth dynamics of pancreatic islet cell populations during fetal and neonatal development of the rat

“…PP cells were observed in quantity at 18 days of gestation in this study. In fact, PP cells were observed as early as 14 days of gestation in rats (unpublished observation; Fujii, 1979).…”

“…However, suggestions of a neuronal origin for the endocrine cells have also been made (Pearse, 1977;Alpert et al, 1988). In the rat, the various endocrine cell types B (insulin), A (glucagon), D (somatostatin), and PP (pancreatic polypeptide) cells appear independently at different times during gestation (Pictet and Rutter, 1972;Sundler et al, 1977;Fujii, 1979;Yoshinari and Daikoku, 1982). The endocrine cells first appear as single or small clusters of cells within the general epithelial matrix.…”

Co-localization of neuroendocrine hormones in the human fetal pancreas

“…Earliest in the evolution among endocrine cells are the glucagon-immunoreactive (IR) cells, known from the incipient formation of the pancreatic buds, followed by insulin-IR (4,5), somatostatin-IR and PP-IR cells, all four cell types being present by embryonic week (ew) 8 to 9 (6).…”

Ontogeny of Somatostatin Cells in the Rat Fetal Pancreas.

“…Somatostatin inhibits the release of insulin and glucagon from B and A cells, respectively, in the pancreatic islet both in vivo and in vitro [1,7,8,10,11]. Early development of somatostatin cells has not been much studied in detail, although that of A and B cells has been widely investigated in the rat fetus [5,6,[16][17][18]. The present study was performed to determine when somatostatin cells would appear and in what fashion they would grow in the rat fetus, by means of the immunocytochemical technique.…”

“…In the developing pancreatic islet in the rat fetus, A cells first appear on fetal day 11 [6], followed by B cells on day 12 [18]. It is proposed that B cells of the fetal pancreas differentiate by 3 steps [9,13].…”