Comparison of serum oestrogen concentrations in post-menopausal women taking oestrone sulphate and oestradiol.

Mean serum concentrations of oestradiol-17beta, oestrone, and oestrone sulphate in postmenopausal women were the same when measured up to six hours after treatment with either piperazine oestrone sulphate 1.5 mg or oestradiol valerate 2 mg. Maximum concentrations of oestradiol were less than those of oestrone, but oestrone sulphate reached concentrations about 30 times higher than those of oestrone. The rapid conversion of oestradiol valerate to oestrone and oestrone sulphate does not support the suggestion that in menopausal women oestradiol is less likely to be associated with a risk of endometrial carcinoma than oestrone sulphate, since the two preparations appear to become identical after ingestion.

PIP: In 17 postmenopausal women who were taking estrogens for menopausal symptoms, 10 were taking estradiol valerate, 2 mg daily, and 7 were taking piperazine estrone sulphate, 1.5 mg daily. All stopped these treatments 48 hours before the study began. Blood samples were then taken before and at 2, 4, and 6 hours after estradiol 2 mg or estrone sulphate 1.5 mg. Radioimmunoassay techniques were used. There was no significant difference between the 2 drugs in the 3 estrogen serum concentrations. Estradio concentrations remained the same, while estrone and estrone sulphate showed a 4- to 8-fold rise over pretreatment values. Results suggest that these 2 estrogen preparations have identical effects on the serum concentrations of 3 major estrogens. There was wide variation among patients and during phases of the menstrual cycles. Taking estrone sulphate seemed no more likely to increase risks of endometrial carcinoma than ingesting estradiol since the 2 preparations become identical during metabolism.