4. How do endocrine disruptors work?

The activity of low-dose PEs depends on their affinity for nuclear receptors (e.g. tributyltin's high affinity for the PPARγ receptor).

It may also depend on the number of receptors available, or their power of action.

EPs can act on several levels, including :

• on hormone synthesis;

• on transport ;

• on metabolism;

• on nuclear receptor (NR) binding;

• by disrupting the synthesis of NR ligands;

• by altering protein binding to sex hormone binding globulin (SHBG);

• by altering binding to the thyroxine transport protein (transthyretrin);

• by modifying the clearance of...