Distribution of G-cells in the antrum and duodenum and D-cells in the fundus, antrum, duodenum and pancreas of the guinea pig.

Antral and duodenal G-cells and fundic, antral, duodenal and pancreatic D-cells were demonstrated immunocytochemically and their population size was estimated in guinea pigs of both sexes. The population of antral (210 + 18.03 SD cells/cm) and duodenal (13.20 + 3.12 SD cells/cm) G-cells is lower in guinea pigs than in dogs. Antral and duodenal G/D-cell ratios (1.6/1 and 1.2/1) are also lower in the guinea pig than in man. Antral G- and D-cell populations are greater in male (210 + 18.03 SD cells/cm and 128.2 + 17.63 SD cells/cm) than in female (176 + 13.8 SD cells/cm and 108.4 + 6.9 SD cells/cm) guinea pigs. The percentage of pancreatic D-cells is greater in the guinea pig (20-25%) than in man and rat. It is concluded that the differences in gastric and duodenal G- and D-cells between guinea pigs and other species possibly reflect different gastric secretory functions. Sex related differences in the endogenous sex hormones can explain differences in gastric secretion between the two sexes. Pancreatic D-cells possibly exert their action on neighbouring endocrine cells through different pathways from those seen in man and rat.