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Development of pancreatic endocrine cells in the rat fetus
Insights
The study reveals that glucagon-producing cells are the earliest pancreatic endocrine cells to develop in rats, appearing by day 11 of gestation. Other endocrine cells, including insulin and pancreatic polypeptide cells, emerge later, supporting a foregut origin for most pancreatic endocrine cells.
Area of Science:
- Developmental Biology
- Endocrinology
- Cell Biology
Background:
- The prenatal development of pancreatic endocrine cells is crucial for glucose homeostasis.
- Understanding the origin and differentiation of these cells provides insights into pancreatic diseases.
Purpose of the Study:
- To investigate the temporal and spatial development of rat pancreatic endocrine cells during gestation.
- To determine the origin of different pancreatic endocrine cell types.
Main Methods:
- Immunoperoxidase staining technique was employed to detect specific endocrine cell markers.
- Rat embryos at various gestational ages were analyzed for cell differentiation and distribution.
Main Results:
- Glucagon-producing cells were the first to appear on gestation day 11, originating from the foregut epithelium.
- Insulin, pancreatic polypeptide (PP), somatostatin, and gastrin cells emerged between days 14 and 18.
- PP cells showed a peripheral localization within developing islets and had counterparts in the fetal duodenum.
- Glucagon-like immunoreactivity was also observed in neuronal cells of the duodenal Auerbach's plexus by day 19.
Conclusions:
- The findings support the hypothesis that most pancreatic endocrine cells are derived from the foregut epithelium.
- The study elucidates the sequential development and differentiation of pancreatic endocrine cell populations.
- The presence of glucagon-like immunoreactivity in duodenal neurons suggests potential neuroendocrine interactions.
Abstract:
Prenatal development of rat pancreatic endocrine cells was investigated by the immunoperoxidase technique and the following results were obtained: 1) Glucagon immunoreactive cells are 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 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.