Humans, worms share ancient estrogen bond.

Dec 28, 2008

Keay J and JW Thornton. 2008. Hormone-activated estrogen receptors in annelid invertebrates: implications for evolution and endocrine disruption. Endocrinology doi:10.1210/en.2008-1338.

Synopsis by Jennifer Adibi

Researchers confirm for the first time that a worm has estrogen signaling capabilities, just like people and other back-boned animals. The invertebrate shares both the good -- and detrimental -- functions.

The findings support the idea that environmental policy-makers should consider the deleterious effects of pollutants in species at all levels of the food chain, and not just in humans and furry animals.

Until now, invertebrates were not known to have the same type of estrogen signaling systems as humans and other vertebrates. The system works like this: the estrogen hormones bind to a molecule called a receptor. The binding sparks a complex signaling path that leads to the effects associated with the hormone, such as specific tissue development or cell growth.

The estrogen receptor plays a fundamental role in reproduction, development and behavior but unfortunately, is also a target for environmental pollutants that mimic estrogen. 

Researchers found that the estrogen receptor in the annelid worms was similar to the vertebrate receptor and equally capable of binding to environmental chemicals such as bisphenol A (BPA) and 4-octylphenol, two widespread environmental pollutants that are released from plastics.

This study shows clearly that animals considered of ancient origins had a primitive form of the estrogen receptor, even before vertebrate and invertebrate species diverged. The receptor -- which performs similarly in the worms and in people -- has not changed much in form and function over the course of evolutionary time.