Show of hands.  How many of you out there believe that the fat cells are essentially waste receptacles of goo whose sole purpose is to house those excess Snicker’s bars, bags of Oreos and cans of Pringles?  

I’m about to blow your mind.  

Your fat cells are very much an active endocrine gland.  That’s right!  Your adipose tissue, that stuff that just hangs about over the top of your jeans, is actually a ‘factory’ of inflammatory chemicals called cytokines but also churn out hormones.  (This is why extra weight exacerbates estrogen dominance as the fat cells store excess estrogen but also create even more which is then released and circulated creating a very serious issue.)  

Two of the hormones these adipocytes produce are leptin and resistin.  The latter we will talk about at a later date because it is still relatively unstudied (though studies are expanding every day) by the scientific community.  

Today, the star of the show is leptin, an adipokine, a neurotransmitter released from the fat cells that is the master hormone responsible for energy in the body.  It enters the brain through the hypothalamus via a complex signaling system.  (We will be talking about the hypothalamus at length shortly while discussing the HPA axis but you need to understand now that the hypothalamus connects the brain to the endocrine system.)  Now we know the brain is a busy organ.  It, as the master of the nervous system, has to keep track of every function of the body at the cellular level and bark out orders to keep those functions working properly. Luckily it has help.  Leptin acts as the gauge for the energy status so the brain knows exactly how much energy it has at any given moment.  It tells your brain when the cells are fed and energy stores are adequate.  When the body is properly nourished and there is proper energy to provide the cells the appetite is suppressed and we stop eating.  (Conversely, when leptin measures that the cells are running low on energy it alerts the brain which tells the stomach to release ghrelin (our ‘hunger’ hormone) which makes food look good so we eat to fuel our bodies.  

Isn’t the body an amazing creation??  

the role of leptin in the body 

If you haven’t done the math yet, Leptin is a major factor in weight control.  When everything is working properly, leptin tells us when we need to eat and when we have provided sufficient energy to our bodies so we can stop eating.  In our next post we will be talking about Leptin Resistance and what happens when it all goes wrong.  (Hint:: Your thyroid plays a HUGE part in this!!) 

Leptin is not only responsible for measuring energy expenditure and creating a ‘long term spending plan’ based on the perceived available food supply but also plays a huge role in many organ systems.  One such system is bone formation as bones are constantly forced to remodel due to stress from fractures and other injuries.  This physiology requires a massive energy expenditure and depends on leptin to do its job to tell the body that it needs enough energy to support this function.  

Leptin plays a part in immune modulation and its role in fertility is notable as fertility and pregnancy requires an enormous amount of energy.  In fact, I can’t think of a single organ process in which the energy needed to make everything run smoothly isn’t dictated, in some way, by leptin telling the brain whether or not there is enough energy for the proper functioning of any given cellular activity.  

It is also imperative that leptin function properly in the body in order to create other hormones in the body.  If leptin is unable to convey the need for proper energy intake it puts a strain on the other endocrine glands which are responsible for creating all other hormones in the body.  If leptin production or signaling is not working to plan the body signals the endocrine glands to slow down production of hormones.  (This is a very simple explanation although the complicated explanation is several posts in and of themselves.)

Leptin is one powerful player in the symphony of balanced health and vitality. 

Tomorrow we are going to be talking about what happens when something goes wrong with leptin and the body experiences leptin resistance.  See The Lowdown on Leptin Pt. 2

Stay tuned.