The first rule of toxicology is that the dose is the poison. That is, every
substance is toxic if given at a high enough dose. Toxicity testing in animals (usually
rodents) is required for investigational new drugs. The EPA does toxicity tests on
environmental chemicals through the National Institute of Environmental Health
(NIEHS) and the Environmental Toxicology Program (ETP). They give very large
doses of test chemicals to rodents to see if they might be harmful to the small portion of
humans who are highly susceptible to the test chemical. GLP was formulated by the US
Food and Drug Administration (FDA) to regulate non-clinical studies on the safety and
possible toxicity of a new compound. The European Medicines Agency (EMA) has its
own GLP regulations that overlap with the FDA GLP. Every GLP study must have a
study director, who writes a study protocol and is responsible for the design, conduct
and reporting of the study. Many GLP studies also have principal investigators (PIs). In
contract labs that work for the NIEHS, there is a single PI who has overall responsibility
for the GLP studies. The PI must approve of all study protocols and any amendments.
Keywords: Toxicology, EPA, NIEHS, ETP, GLP, principal investigator.
