Effects of lithogenic diets on mouse gallbladder epithelium. A histochemical, cytochemical and morphometric study.

Mice fed a cholesterol-cholic acid-containing lithogenic diet developed gallstones within 2 months. The gallbladders were grossly distended and morphometric studies of the gallbladder revealed a significant epithelial hyperplasia after 2 weeks. Based on results obtained with histochemical techniques an increase of glycoproteins could be demonstrated in the principal cells of the invaginations and crypts in the gallbladder mucosa after 2 weeks. At the ultrastructural level the principal cells showed increased numbers of secretory granules and in crypts so-called gland cells with large amounts of secretory droplets appeared. There were numerous signs of excytotic release of cell secretory products during gallstone formation. The findings suggest an increased synthesis of glycoproteins in the gallbladder epithelium and an enhanced secretion prior to or concomitant with gallstone formation.