Epithelial surface changes and induction of gallstones in the male Syrian hamster gallbladder as a result of a two-month sex steroid treatment.

Transmission (TEM) and scanning (SEM) electron microscopic observations were correlated to characterize morphologic changes induced in the gallbladder of male Syrian hamsters following a two-month estradiol (E) and estradiol + medroxyprogesterone (E + MP) treatment. Compared to control (C), E-treated surface epithelial cells show pleomorphism, cytoplasmic vacuolizations, apical granules, excrescences and decapitations, and small gallstone-like deposits. Following both E + MP treatment, a large accumulation of apical granules containing acidic mucoid products, abundant intraluminal deposits and numerous fields of observation suggest that cell debris and mucous condensation could participate in the formation of the large intraluminal gallstone-like deposits detected as a result of this treatment. In control gallbladders these events were never observed. MP added to E also increases liver and gallbladder weight as well as blood lipid levels. These findings complement and confirm other previous data obtained following short steroid treatment in male, ovariectomized and intact female hamsters. In addition, these results support our hypothesis that gallstone nucleation and growth originate from multiple factors, hormonal disturbance, modulation of liver lipid metabolism, production of cell debris and mucus, can be responsible for the initial gallstone nucleation.