A protein made by the liver, that can also relieve into the blood stream is sex steroid binding globulin.Sex steroid binding globulin which can also be called as sex hormone binding globulin is a glycoprotein which combines the two hormones that are related to sex: estrogen and androgen. There are also few other steroid hormones like cortisol, progesterone and other corticosteroids. Apart from birds, SHBG can be seen in most of the vertebrates. Apart from Liver, the other sites that produce it are the testes, brain, placenta and uterus. Its main job is to transport the hormones (Estrogen and Testosterone (which are androgens)) to other tissues of the body by entire blood stream. When compared to estrogens, Sex hormone binding globulin has more affinity for Testosterone and Dihydrotestosterone (DHT). Therefore, it plays an important role in managing the delicate balance between in women’s body between testosterone and estrogen. The main function of this SHBG is to check that these hormones are carried to entire body to ensure that it is available to the tissues that are in need of it. SHBG optimal levels decrease a women’s risk of type 2 diabetes. Even with the intake of few hormones like androgens synthetic progesterone’s related to norethisterone, anabolic steroids are the results for lowering sex hormone-binding globulin.
Few conditions like obesity, hypothyroidism, acromegaly (the state where production of growth hormone is high by body) and Cushing’s syndrome are also the results for the low levels of SHBG.Even the insulin resistance without obesity will also cause in lowering the SHBG levels.
Women with higher testosterone levels have more chances to have the lower levels of SHBG that may often lead to androgenization (masculine characteristic development).
Some of the causes of low SHBG are:
- Excessive androgen activity
- Polycystic ovarian syndrome
- Insulin resistance\diabetes
There exists the higher risk in women when compared to men like metabolic syndrome, cardiovascular diseases, hair growth or hair loss (male patterned), irregularities in menstrual cycle, skin abnormalities, type 2 diabetes and skin abnormalities in low SHBG.
Naturally women in comparison with men, tend to have the higher levels of SHBG. Young women have more chances to have higher SHBG levels, when compared with postmenopausal women. This is mainly because of the aging process. Even during pregnancy SHBG levels are increased and also with regular uses of oral contraceptives will lead your SHBG levels higher. There is a chance for causing higher than normal levels of SHBG in thyroid hormone treatment and anorexia nervosa in women. Some of the causes for high levels of SHBG are:
- Birth control pills
- Increased conversion of testosterone to estrogen
- Liver cirrhosis
- Extreme weight loss in anorexia nervosa
- Fibrocystic disease(breasts)
- Stress with elevated cortisol
Testosterone role is important as it is the reason for maintaining muscle development, bone health, sex drive and energy levels. Unfortunately, women with excessive levels of SHBG have less available of testosterone in their bodies.