Marked elevation and cyclic variation of corticosteroid-binding globulin: an inherited abnormality?

Unexplained high serum corticosteroid-binding globulin (CBG) concentrations [mean values, 78.8 and 55.7 mg/L; normal women, 38.8 +/- 3.8 (+/- SD) mg/L] were found repeatedly in two apparently healthy sisters who were not pregnant or taking exogenous estrogens. One had substantial variations in serum CBG and sex hormone-binding globulin concentrations during the menstrual cycle, which paralleled the normal cyclic changes in serum estradiol. The other woman was postmenopausal and had a high serum CBG concentration despite of low serum estradiol levels. We conclude those women have an inherited abnormality in CBG production.