Lead biomarkers linked with stress

Lead has been used throughout human history, from its first smelting in around 6400 BC to its use in petrol (gasoline) in the 20th century. Lead poisoning has a long history as well--in fact, it was once thought to have caused the decline of the Roman Empire. Lead poisoning symptoms can range from headaches in adults to learning disabilities in children, and though it's a lot less common that it once was, lead poisoning still occurs in poorer areas and in people exposed through work. High levels of lead in the blood (a biomarker of recent exposure) and in the bone (a biomarker of long-term exposure) are linked with an increase in levels of a stress hormone (plasma adrenocorticotropic hormone  or ACTH) after a stress test. This suggests that lead exposure, both acute and chronic, could change people's hormonal responses to stress, and could also indicate other biological dysfunctions over and above those caused by lead's neurotoxic effects. Abstract