Effect of estradiol upon serum enzymes in primary biliary cirrhosis.

The repeated observation of a fall in serum enzymes at midmenstrual cycle in an untreated patient with primary biliary cirrhosis stimulated a study of estrogen administration in five patients with primary biliary cirrhosis. One patient was premenopausal, one patient was postmenopausal and three had had oophorectomy. After 2 weeks of ethinyl estradiol, AST was under 100 IU per dl in all and had decreased by 50% or more in 4 of 5 patients. gamma-glutamyltransferase and alkaline phosphatase fell by 50 and 30% or more, respectively, in all patients. The decreases in serum enzymes were statistically significant in all patients for gamma-glutamyltransferase, in 4 of 5 for AST and in 3 of 5 for alkaline phosphatase. One patient developed increased icterus leading to withdrawal of estradiol. Withdrawal of estradiol was followed by return toward control values over variable periods, usually 1 to 4 weeks. Repeated courses of estradiol reproduced these enzyme changes. These observations indicate that estradiol in the doses used (0.05 mg per day) reversibly lowers serum enzyme values in biliary cirrhosis. The mechanism of the effect is unexplained, but an immune system alteration may be responsible.