Protection Agency (EPA) has developed a battery of screens and tests to
evaluate endocrine activity, the majority of which are animal-poisoning
studies. The Endocrine Disrupter Screening Program (EDSP) is organized into
a two-tiered screening program: Tier 1 screening assays (the Tier 1 battery) are
intended to detect chemicals with the potential for endocrine activity (estrogen,
androgen, or thyroid), and Tier 2 tests to determine whether such interactions adversely affect reproduction.
The first phase of Tier I testing began at the end of 2009.
Below is a summary of
each of the screens and tests. Methods included in the Tier 1 battery have been
finalized, and the EPA is in the process of developing and validating the Tier
2 tests. Click here for detailed information about each of the
assays and for up-to-date information on the status of each Tier 2 assay in the
Tier 1 Screens
Tier 1 consists of 11
assays, five in vitro (non-animal) tests,
and six in vivo (animal) tests. In vitro tests use proteins, cell lines, or
tissues to examine biological activity on a microscopic level. In vivo tests use rats, mice, frogs, and
fish who are killed at the end of the experiment. In vitro studies save time and resources and use many fewer animals
(for cells or tissue samples) or no animals at all.
Tier 2 Tests
Efforts are underway at
the OECD to assess each of these methods, review them for relevance, and
minimize the numbers of animals used. The OECD is also working to create a new
mammalian reproductive test guideline that does not generate a second
generation, saving the majority of animals used in the standard 2-generation
What is the Cost?
Performing all the tests
for a single chemical of the current Tier 1 battery would use a minimum of 536 to 554
animals and cost a minimum of $384,995 per chemical (conservatively
estimated, with no range-finding or repeat experiments; Table 1). If all tests were performed for all 67 Phase I chemicals
selected for Tier 1 screening, the first phase of the EDSP would likely use more than 35,000 animals
and cost at least $25,794,665.
Table 1: Cost of Tier 1 Assays1 and Number of Animals
Number of Animals Used
Unknown for uterine extract
Unknown for testes extract
Fish Short-Term Reproduction
Analytical Method Validation
1Low and high cost data was obtained from price
lists for two contract research laboratories: Harlan (November 2009) and
Smithers Viscient (January 2010).
2Estimated from relevant OECD Test Guidelines.
Almost all of us grew up eating meat, wearing leather, and going to circuses and zoos. We never considered the impact of these actions on the animals involved. For whatever reason, you are now asking the question: Why should animals have rights? Read more.