Tell me about hormones.
What would happen if women took testosterone?
If men took estrogen?
(I think I knew some men who did this to grow breasts)
What happens if one has not enough of the required hormone?
Hormones provide a major way for cells of the body communicate with each other. They also allow one organ to control or influence another.
So, for example, one hormone may signal the liver to start making sugar, or tell the kidney to hold onto salt. Another hormone may signal virtually all the body’s cells to tell them to speed up whatever they’re doing.
Hormones are secreted by glands. Examples of glands are the thyroid, pituitary, adrenal, testes, and ovary.
Some hormones made by one gland tell other glands in the body to make other hormones.
Some hormones are necessary to sustain life (eg. cortisol). Some are not life-preserving or sustaining, but are required for various other functions (eg. estrogen).
Some of the main hormones in humans (there are actually scores of them) are:
cortisol
thyroid hormone
estrogen
testosterone
growth hormone
insulin
As mentioned, the levels of many of the hormones in the body are controlled, in turn, by other hormones in the body. Many of these controlling hormones come from the pituitary gland (which is attached to the bottom of the brain).
All of the major hormones can now be replaced in people who are missing them (or, at worst, a substance can be given to them that mimics the action of the missing hormone).
People can be missing hormones because of congenital problems, tumors, infections, …
Sometimes, people can have an excess of certain hormones (eg. a tumor that produces a particular hormone). Often, this leads to diseases/syndromes.
To answer your specific questions:
If a man takes estrogen, it will turn off his body’s normal production of testosterone. The resulting high levels of estrogen and low levels of testosterone will lead to some breast enlargement, shrinking of the genitalia, decreased beard growth, and the like.
Women who take testosterone (or who have a tumor or disease that causes excess testosterone production) will develop increased facial and body hair, may start to grow bald, may become more muscular, get acne, etc.
The science of hormones is called ENDOCRINOLOGY. Of course, it is huge. What else, if anything, would you like to know?