Differential growth rate of rat gastric mucosal cells during postnatal ontogeny

The growth rate of surface epithelial, chief, and parietal cells of the base and neck of oxyntic glands was studied in the albino rat by comparing morphometric measures at days 15, 21, 30, and 100 postnatally. All cells increased in size. The number of cells per micrometer squared increased rapidly for chief cells and base parietal cells, while neck parietal cells remained constant and surface epithelial cells decreased. There was a net increase in the volume density of parietal and chief cells and a slight net decrease in surface epithelial cells during postnatal development. In a second experiment, the effects of early weaning on these variables was studied. Early-weaned rats gained less body weight than normally weaned counterparts. The change in surface epithelial cell size was not affected by early weaning. However, parietal and chief cells grew more quickly, initially, in early-weaned rats than in normally weaned rats. Cell numbers were unaffected except for an initial decrease in relative number of neck parietal cells. One long-term effect of early weaning was noted. The size and volume density of neck parietal cells in early-weaned rats was smaller, in the adult animal, then in normally weaned rats.