Effect of female sex hormones on lithogenicity of bile.

Effect of female sex hormones on lithogenicity of bile was investigated in an attempt to explain the female preponderance of cholesterol gallstones in man. Estrogen in a form of Estradiol valerate or progesterone in a form of 17 alpha-Hydroxy-progesterone caproate was administered to female dogs oophorectomized to negate influence of endogenous sex hormones from the gonads. Gallbladder bile was puncture aspirated at intervals before, during and after the administration. Lithogenicity of the bile increased markedly during the administration of estrogen. The increase was not so pronounced during the progesterone administration. The increase of lithogenicity is apparently mainly due to increase in the absolute concentration of cholesterol. Differences in the effect of estrogen and progesterone suggest the presence of fluctuation of lithogenicity of bile during the menstrual cycle and pregnancy.