For Grace,
I found lots of good information on hormones, pain and the brain (and how some women stop ovulating when they are injured, underweight, taking allot of medications, etc. - if they stop ovulating, their bodies do not produce as much progesterone).  Progesterone seems to have neuroprotective qualities. 

They are doing a study on Traumatic Brain Injury (TBI) patients and intravenous progesterone (reduces inflammation in the brain & better recovery).  All very interesting stuff.

http://www.medicalnewstoday.com/articles/179836.php

A randomized, double-blind Phase III clinical trial, involving approximately 1,140 patients over a three-to-six year period using the hormone progesterone to treat traumatic brain injury (TBI) will start in March 2010 at 17 medical centers across the USA. The National Institutes of Health (NIH) is funding the grant, which was awarded to Emory University.
I have lots more information which I can forward on to you, if you are interested.

I hope you are having a great day!
Irene Turner