Many steels add to the iron-steel mix other metals that give the entire substance desirable properties such as strength, heat resistance, or flexibility. Steel is considered a mixture rather than a compound because the iron does not chemically bond with the carbon and other components.
Some of estrogen's effects include: 1  Increasing serotonin, and the number of serotonin receptors in the brain. 2  Modifying the production and the effects of endorphins, the feel-good chemicals in the brain. 3  Protecting nerves from damage, and possibly stimulating nerve growth.
They could also help generate some new ideas on how estrogen in fat may influence why postmenopausal women tend to accumulate more fat in the abdomen. The authors suggest that more research is necessary to better understand the mechanisms behind how and why estrogen acts in these differential ways.