Okay so we've all heard of hormones and, if like me you managed to survive your teenage years, you probably have a fair idea what they can do to your body (and your mood). Teenage girls becoming moody and boys getting aggressive is always brushed aside with "it must be the hormones" which at times makes us wonder why we even need them anyway. For most of us, we will have been taught about hormones when we had a sexual education class at school, or perhaps by a parent/guardian, but what you don't realize is that you were only really taught about three or so hormones at best... Testosterone, Progesterone and Oestrogen. And you may have heard of a few other popular ones like insulin and adrenalin. So without further ado, let me change your perception of hormones forever with five hormones you are certainly glad you have with this medical students guide.
Ghrelin is one of my favourites, simply because I have a huge appetite. Its often termed the hunger hormone and for a very good reason as without it we wouldn't feel the need to eat. It was first reported in 1999 and it is a Growth Hormone Realising Peptide (hence ghrelin). It primarily acts on an area of the brain known as the hypothalamus to increase our appetite and change our feeding behaviour accordingly, encouraging us to raid the snacks cupboard. Levels in our blood stream peak right before meal so the longer we go without eating, the more Ghrelin is produced and the more our stomach cries out for us to eat something already. Who knows maybe this is why we get 'hangry.'
This hormone might not be high up on anyone's list but for me if most certainly deserves to be here and for two very good reasons. Firstly its the best sounding hormone out there and in case you can't pronounce it here it is phonetically Co-lee-sisti-kinin. I know its good right as far as hormones go anyway. Secondly without it, we humans would have virtually no ability to break down fats and other substances entering the small intestine. This is because CCK causes the release of pancreatic juices containing important enzymes necessary for this function. In the absence of CCK and without these enzymes you would develop a condition called Steatorrhea and if your feeling brave enough go ahead and look that up on Google images (maybe not if you've just eaten). This for me is why CCK is a very necessary hormone indeed.
So in all likelihood you've heard of insulin and know that it works to decrease blood glucose levels and without which we develop diabetes. But did you know there is a hormone that does the exact opposite of insulin and as a student who regularly has late nights studying I'm very glad that glucagon does exist. Essentially your body wants to maintain your blood sugar level in a very specific range, anywhere between 4-8mmol/L depending on when the last meal was. Any excess is converted to glycogen, which is the storage form of glucose. So when you are playing sports or studying hard and haven't eaten in a while, instead of your blood sugar level dropping dangerously low, glucagon is secreted from the pancreas and converts glycogen back to glucose, thus saving the day. Genius!
This is the only hormone mentioned here that sounds kind of negative, I mean what if I like my diuretics, what did they do wrong? Well the truth is most people really do love diuretics but perhaps not the consequences they produce. Have you ever wondered why you can have the best bladder in the world but as soon as you're having beers with your mates you're like a heavily pregnant woman who needs to go to the bathroom every 15 minutes? That's the power of the diuretic. Of course other diuretics are available such as coffee, tea and other caffeinated drinks. Naturally a diuretic wants to increase diuresis, or the production of urine, and the clever clogs reading this will already have worked out that anti-diuretic hormone (ADH) does the exact opposite. It is released by the pituitary gland when the amount of water in the blood drops, and you need to conserve water (most likely because you got stranded on a desert island without supplies), and acts on the collecting tubules in the kidney to produce less urine and save more water.
If like me you have a very pale complexion you'll know the horror of spending time in the sun only to get burnt instead of tanned and not even a factor 50 sunscreen helps. If you are lucky enough to have a perfect tan you may be aware that the pigment responsible for skin colour is called melanin and it is produced by melanocytes in the skin. And if you're perceptive enough yes there is a hormone that influences your tan, I know its amazing. This hormone stimulates the melanocytes to produce more melanin as a protective measure against the suns harmful UV rays, and over the years, we have attributed this look as an attractive cosmetic one. So for me being a very pale Irish man why don't I quit sunbathing and dose up on some MSH instead? Sadly for those of us that don't tan well part of the problem is variations in our MSH receptors causing us not to respond as effectively to this hormone. Oh well, hopefully some day the burnt look will become fashionable.
Hopefully now you can see that hormones do far more that alter our mood and make us passive aggressive teenagers. They are permanently with us throughout our lives, and are extremely important chemical messengers in our bodies that can perform a wide and varied range of tasks that most people are very much unaware of. So next time someone says "it must be the hormones" ask yourself which hormone could it be?