Description
Sex hormone-binding globulin (SHBG) is a glycoprotein that binds to the sex hormones androgen and estrogen. SHBG is produced mostly by the liver and is released into the bloodstream. Other sites that produce it include the brain, uterus, testes, and placenta. It has both enhancing and inhibiting hormonal influences. It decreases with high levels of insulin, growth hormone, insulin-like growth factor 1 (IGF-1), androgens, prolactin and transcortin. High estrogen, andthyroxine cause it to increase. It has been found that the monosaccharides glucose and fructose reduced human SHBG production by hepatocytes, irrespective of the presence of insulin, by downregulation of hepatocyte nuclear factor-4A and replacement of HNF4A by COUP-TFI at a cis-element within the human SHBG promoter, coincident with repression of its transcriptional activity