Quantitative morphology of endocrine cells in human fetal pancreas

Sections of pancreas from human fetuses, 6-20 weeks gestation, were stained with immunoperoxidase for insulin (B cells), glucagon (A cells), pancreatic polypeptide or somatostatin (D cells). Morphometric analyses were performed on sections from head and tail regions of each fetus. No stained cells were found at 7 weeks. A, B, pancreatic polypeptide and D cells were found at 9 weeks in primitive islets or as isolated cells adjacent to duct cells. There was no relationship between the density of each endocrine cell type and fetal age, but there was a significant increase in the relative density (percentage total endocrine cells) of D cells from 10-20 weeks (p less than 0.01). The tail contained significantly more A cells (p less than 0.05) and less pancreatic polypeptide cells (p less than 0.01) than the head but similar densities of B and D cells. Lobules containing a high density of pancreatic polypeptide cells and few A cells were found in the posterior part of the head in six fetuses, aged 10-20 weeks.