I need information on how some hormone levels change across the life
span. The hormones I want to know about are hormones related to sexual
activity, that is (as far as I've read) testosterone for males and
estrogen for females. A graph that shows how it increases and
decreases through years would be great. Verbal information would do
too.
I'm not from the field. I thought finding that should be sth
straightforward. I searched some textbooks and also the internet. But
the closest thing I could find was the change in estrogen level
through one menstrual cycle.
Thanks in advance,
Elif Kus

In males estrogen levels are high during brain development (before
birth), and then fall off, I think they then remain fairly constant. 
Also in males, testosterone (T) levels hit a spike during development
of the sexual organs (again before birth), and at this time are as
high as they will ever be.  They then fall off to a lower level.  At
puberty they again go up and stay up as long as the testis remain in
the body.  At this time, they are at a level called saturating,
meaning that adding more testosteron to the blood will actually not
have an effect.  Hope this helps some.

Elif --

A useful book in understanding hormones generally and their role in
body formation, sex and human functioning is the 1993 book by science
writer Matt Ridley, "The Red Queen: Sex and the Evolution of Human
Nature."

It won't give you a specific measure for each age but rather explain
the role of hormones in human development -- including the fetus. 
Note that a lot has happened in genome research since Ridley wrote
that book.  Perhaps someone more in tune with the science can suggest
a more up-to-date resource.

Best regards,

Omnivorous-GA

Thank you Zn833 for your answer.. (That looks now like a line from a
science-fiction book of a black future world. human No:879457549 :) )
I actually was expecting sth like the androgen hormones increase from
17-20, and make a peak at 21 and drop until 30 then increase again..
(I made up every age of course) But well, that I imagined sth like
that doesn't mean that there has been done such a longitudinal study
or that it is possible to be done. Your answer gives me a general
picture still, so I might be able to use it.
And thank you Omnivorous..  I am writing a thesis on mate choice. I've
been told to read it about 5 times by my supervisor. Having heard it
one more time I will read it. I'm writing a simulation that is
supposed to simulate some mate-choice behaviour. And there is a
variable that corresponds to the willingnes to mate. There are some
variables that effect it. I know that hormones play an important role
in that through a neuroscience course I took and probably through
everyday knowledge. For example I've heard that some women feel a
desire to have a child when they are in their early thirties. I
thought that this must have been hormone related. And I thought I
could include the effect of hormones into my thesis by making it
effect this willingness variable.

Elif --

If you're writing a thesis, you'd find all of Ridley's books
interesting.  Being a science journalist, he writes for a broad
audience but footnotes very well, so you can go back to the original
sources.

I find, as you can tell from my previous comment, that "The Red Queen"
is a bit dated, though I have to admit that it's very on-topic for
what you're studying.  More up-to-date and also on-topic is his book,
"Nature via Nurture":
http://www.amazon.com/exec/obidos/tg/detail/-/0060006781/qid=1098973613/sr=8-1/ref=pd_csp_1/102-9567084-2762523?v=glance&s=books&n=507846

Best regards,

Omnivorous-GA