Quantitative morphology of B, A, D, and PP cells in infants of diabetic mothers.

Pancreatic specimens from 34 infants of diabetic mothers (IDM) and 32 control infants of gestational ages 26-44 wk were examined histologically using immunocytochemical stains for insulin, glucagon, somatostatin, and pancreatic polypeptide (PP). Each section was divided into PP-rich and PP-poor regions that are thought to be derived from the ventral and dorsal lobes of the gland, respectively. In some of these, the fractional area (%) occupied by positively stained B, A, and PP cells was determined by automatic image analysis, and the area occupied by D cells was determined by conventional point counting. The B cell fractional area was significantly higher in the IDM in both PP-poor and PP-rich areas (P less than 0.02). the fractional area of A cells in PP-poor areas and of PP cells in PP-rich areas was also significantly greater in IDM (P less than 0.02). The total endocrine cell fractional area was significantly greater in IDM in PP-poor but not in PP-rich regions of the pancreas. These results are not compatible with the hypothesis that maternal hyperglycemia results in specific fetal B cell hyperplasia and raise the possibility that hyperplasia of B, A, and PP cells in IDM may result from a variety of stimuli or that one stimulus acts on a pluripotential stem cell.