There are many variables which affect whether a hormone disrupting chemical has a biological effect, including uptake, distribution, nature of action and time of action. These points are discussed in more detail here. For more detail and references, see Toppari et al. First the chemical must enter the body, through ingesting food or drink, being absorbed from cosmetics or inhaled. The chemical will then be distributed through the body, usually by the blood.
Several systems exist in the body to detoxify chemicals, notably the liver enzyme systems.
These systems remove chemicals by a combination of breaking them down and attaching them to other chemicals, which promotes their excretion, usually through the kidneys and into the urine. Some chemicals are not removed effectively by these processes, so remain in the body. The fat stores of the body can be mobilised during stressful periods, malnutrition, or in pregnancy, releasing the stored chemicals into the blood stream. WWF have recently published a disturbing review of all the chemicals that have been found in body fat and breast milk - see the issues page for more details. Sex hormone binding globulin binds very strongly and specifically to oestradiol, whilst albumin binding is weaker and less specific.