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 ga llbladder surface epithelial changes, and intraluminal deposits. These changes include excrescences in various stages, bulging, and extrusio n of material from the epithelial cells. The most striking scanning el ectron microscopic observations are the dramatic events, comparable to apocrine-like secretory events observed in another related study usin g oophorectomized hamsters. Since the hamster gallbladder does not pos sess mucous goblet cells, it appears that this phenomenon could be a r esponse 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 u sing light and transmission electron microscopy. In control hamsters t hese events were not observed, however, small blebs outlining surface epithelial cells are seen. The results in this report complement the p revious studies using the male and oophorectomized Syrian hamster mode l subjected to similar experimental conditions.