Apical excrescences in the gallbladder epithelium of the female Syrian hamster in response to medroxyprogesterone.

All the intact female Syrian hamsters treated with medroxyprogesterone (MP) for a one-month period, without dietary manipulation, display gallbladder surface epithelial changes, and intraluminal deposits. These changes include excrescences in various stages, bulging, and extrusion of material from the epithelial cells. The most striking scanning electron microscopic observations are the dramatic events, comparable to apocrine-like secretory events observed in another related study using oophorectomized hamsters. Since the hamster gallbladder does not possess mucous goblet cells, it appears that this phenomenon could be a response to the MP treatment, thus providing a larger amount of mucous product than usual with cellular material, in addition to the possible alteration in the quality of the bile following this treatment. As a result of MP treatment, intraluminal deposits were also confirmed by using light and transmission electron microscopy. In control hamsters these events were not observed, however, small blebs outlining surface epithelial cells are seen. The results in this report complement the previous studies using the male and oophorectomized Syrian hamster model subjected to similar experimental conditions.