Sex hormone-binding protein

To secrete a sex-hormone binding protein (SHBP) which binds the sex hormones in the blood to protect them from metabolism and hence inactivation. 

Polycystic ovarian disease. This is indicated by an elevated LH and normal F.SH. Oestradiol measurements are often unhelpful. Hirsutism, a feature of this condition, is associated with raised testosterone and subnormal. sex hormone binding protein concentrations. 

In liver cirrhosis in man the plasma levels of andro-stenedione and estradiol are increased, testosterone are decreased, and the sex hormone binding proteins are increased, with larger amounts of bound testosterone and estradiol. 

Hemopexin (binds heme) Retinol-binding protein (binds retinol) Sex hormone-binding globulin (binds testosterone, estradiol) Thyroid-binding globulin (binds T4, T3) Transferrin (transport iron)... 

Thyroid hormones and most steroid hormones are associated with carrier proteins in the serum. The carrier proteins are called, appropriately, thyroxine-binding globulin, transcortin (for cortisol), and sex-steroid-binding protein. These proteins have a high affinity (Kd 10—9— 10 8 m) for their respective hormones. They buffer the concentration of free hormone and retard hormone degradation and excretion. The carrier proteins are distinguishable from the intracellular receptors for these hormones. 

Orally administered estrogens stimulate synthesis of hepatic proteins and increase circulating concentrations of sex hormone-binding globulin, which, in turn, may compromise the bioavailability of androgens and estrogens... 

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