[Experimental study on the relation of estrogens to gallstone formation]

Estradiol and progesterone were given intramuscularly to seventeen and sixteen male rabbits respectively on every other day for six weeks. After six weeks, gallstone formation were found in all of the rabbits. In two of them there were cholesterol stones in main hepatobiliary ducts. According to the data resulting from estimation of trace elements and lipid components of the gallbladder bile and findings of microscopic and ultramicroscopic examination on the gallbladder wall, the authors suggest that the mechanisms of gallstone formation are probably due to: 1. Estrogens promote nucleation of gallstones; 2. Estrogens raise lithogenic index of the bile; 3. Estrogens cause stagnation of the gallbladder bile.