Sex Hormone Background

Your main sex hormones are estrogen and testosterone.  These are extremely important for women to have interest in sex, typical function in sex and typical experiences in sex. 

 In order to best understand what happens with sex hormones in the body, you have to back up and understand a few concepts first. 

 “Normal” Functions

 The thyroid gland must be working properly.  Estrogen and testosterone production will not be ideal unless the thyroid gland is sending correct messages to other organs.  Strictly focusing on sex hormones here, when normal signals are sent to organs, the ovaries produce estrogen and testosterone and the liver produces a hormone called sex hormone binding globulin (SHBG).  Estrogen and testosterone float in the blood stream.  However, hormones do not do any work floating in the blood stream.  They only begin to work once they find a site to connect to.  If you’ve ever taken a biology class in high school or college, you may have heard of the “lock and key” concept.  The estrogen or testosterone floating around is the “key”.  It finds a receptor site and that site is the “lock”.  Now the estrogen or testosterone can do its job.  Only now is it doing something at all. 

You can think of this like a bunch of people on the highway driving to work.  You’ve got a teacher driving in her Camry to get to school.  You’ve got a plumber driving in her (<— notice that?) F-150 driving to a client’s house.  The teacher and the plumber.  They are on the road.  They want to go to work.  But, if they haven’t reached their destination and actually parked in the parking lot and walked into school and the client’s house, then they aren’t actually working yet.  The teacher isn’t teaching until she is in front of her students.  The plumber isn’t actually “plumbing” until she is working on the pipes.  That’s a lot like these hormones.  They may be on the highway driving to work, but they are useless just driving to work.  They are only useful once they have found their receptor site.

Sex Hormone Binding Globulin: SHBG

SHBG is a protein from the liver.  It gets produced and it ends up finding sex hormones and binding to them.  Like a glob.  It sounds like a big fat nuisance.  I imagine it like a big amorphous blob with globous arms looking for estrogen and testosterone.  It finds the sex hormones and hugs them like a complete idiot and never lets them go.  But, if you they aren’t let go, they cannot bind to their receptor sites and do any work.

It’s like SHBG is a complete idiot driver that asks the teacher and the plumber to pull over on the side of the road and it just sits there and hugs the teacher and the plumber because it is so thankful for their services to the community.  But, SHBG is a fool because in hugging the teacher and plumber and never letting them go, the teacher and the plumber cannot actually go to work.  They are annoyed and stressed about being late to work while clutched in the amorphous arms of a blubbering fool.  This blubbering fool never ever lets them go.  So the principal calls the teacher and the foreman calls the plumber and they both answer their phones and say “Listen!  I’m on the highway.  I’m on my way to work!  But, I am stuck in the embrace of this insanely friendly, but highly socially inappropriate and inept blob!”.  The employers tell the teacher and the plumber that they get no credit for attempting to go to work.  They never made it in and the teaching and the plumbing never got done. 

Blood Work

So…who cares that the teacher and the plumber are on the highway? 

If a tree falls in the woods and no one is there to hear it, does it actually make a sound?

This is the dilemma with blood work and our understanding of blood work. 

Often physicians will do blood work to check estrogen and testosterone levels.  This is only helpful if:

1.      We know thyroid levels are normal

2.      SHBG is also checked

Without checking SHBG, then all we know is that the teacher and the plumber are on the highway, we don’t know if they are actually able to get to work.  If SHBG levels are too high, then we know that the teacher and the plumber are on the highway, but the odds of them being snatched up for a gooey hug by SHBG are quite high.  This tells us a lot.  You might look like you’ve got plenty of estrogen and testosterone, but if the odds of them not making it to work are pretty good, then we need to consider how much estrogen and testosterone is truly being activated in your body.

It’s a ratio game.  It truly is.

Guess what.  In reality, SHBG is rarely checked.  You get told your hormones are fine and you and the physician are left with fewer answers, fewer treatment options and a lot more frustration.