Role of the Ovary in the Regulation of Sex Hormone Binding Globulin and Its Contribution to Peripheral Levels of Androstenedione

In order to assess the role of the ovary in the regulation of the levels of the sex-hormone-binding-globulin (SHBG) and its contribution to peripheral levels of androstenedione, three subject groups were studied: 10 normally menstruating women, 8 postmenopausic women, and 8 postmenopausic ovariectomized women. A basal venous blood sample was drawn between 8:00 to 9:00 h from all subjects in the latter two groups. The blood samples were drawn from the normally menstruating women on days 7, 14, 21 and 28 of their cycles. The following determinations were made in each sample: oestradiol, progesterone, testosterone, androstenedione SHBG, FSH and LH. It was concluded that: 1) SHBG does not vary during the menstrual cycle, nor there are significant differences between postmenopausic and castrated women, and 2) androstenedione levels in castrated women are significantly different from both postmenopausic and normally menstruating women.