Sex-Hormone-Binding Globulin and Body Weight

Female Hirsutism: Pathophysiological Considerations and Therapeutic Implications*

“…increased 5a-reductase activity) with a local overproduction of DHT (98), and a decrease (which has been questioned; see next section) in the number of cytosol androgen receptors (99). This suggestion has also been expressed by the present authors with reference to the plasma free fraction (80,83).…”

“…This percentage has been confirmed by Rubens and Vermeulen in highly selected patients (82). Free T levels seem to be uncorrelated with other clinical or laboratory parameters (83) except as already mentioned, for body weight (80). Although different series reported in the literature are exceedingly heterogeneous with respect to diagnostic screening (many PCO are included) and lab- oratory methods to estimate free T concentration, the feature of a high free T in the presence of normal or only slightly elevated total T, seems to be an unequivocal finding, although not specific for idiopathic hirsutism "since an elevated unbound T has also been reported in "acne without hirsutism (84) and in PCO (85).…”

“…As a matter of fact, no correlation has been found between TeBG and total T (78) and between free and total T (Biffignandi, unpublished results) in hirsute patients, confirming an abnormality of hormone binding in these subjects. The lowering of TeBG in hirsutism is thus probably independent from androgens and appears to be linked to body weight (79,80), although a genetic defect cannot be ruled out. A high free T concentration was detected in about 70% of hirsute women studied in our laboratory (81).…”

“…At a later step, "the adrenal cortex may be involved, and finally, alterations In ovarian function, possibly mediated by changes in hypothalamic-pituitary responsiveness may develop. Defects (congenital or weight-related) of TeBG can be "superimposed in_ §t, least 70% of'the patients with idiopathic hirsutJsm (74,80) causing an additional increase in androgen tissue exposure. * " Although not definitive, this hypothesis seems to explain the various alterations seen in idiopathic hirsutism as different steps of a unique process rather than single defects occurring in different subpopulations of patient.…”