Why Do We Need Hormones?

Key Takeaways

what's the first thing that comes to mind when I say the word hormone pimples mood swings cramps really inopportune moments where your armpits get sweaty we good we're good hormones are obviously involved in puberty but there's so much more than that like hormones are involved in how we deal with stress and in triggering our immune systems and in steroids so grab your antiperspirant and acne cream today we're talking about hormones in a previous episode you heard me talk about blood and all the stuff floating around in it we talked about blood cells and glucose and different biomarkers but I also mentioned chemicals called hormones now I'm assuming that when I say the word hormones you've already heard about testosterone and estrogen but hormones are a much more diverse part of our physiology than just those two hormones or any number of chemical messengers that get secreted by glands travel through the bloodstream and have an effect on cells with receptors for that hormone all around the body they're like a long-distance messaging service in one of our body systems called the endocrine system a system for communicating messages across long distances in our bodies and their effects are incredibly diverse as well hormones can stimulate growth metabolism immune function and much more some hormones even double triple or quadruple dip in their functions around the body for example thyroid hormone is important for development while you're in utero but also in maintaining metabolism in your adult body at the same time multiple hormones can team up to do the same job like controlling blood sugar largely depends on the hormone insulin which is made by your pancreas but it also depends on hormones like glucagon cortisol epinephrine and growth hormone the point is it's really hard to imagine the endocrine system as a single cause and a single effect hormones are less linear and more like a tangley web that's in part because this system is built off of feedback loops mechanisms we're changing one aspect of the loop can lead to increases or decreases of another depending on the situation these feedback loops can be positive or negative which doesn't mean good or bad just how a hormone is affected by some other substance in a positive feedback loop if you increase one factor it also increases another which increases the original factor which keeps the loop going to quote a late 90s trip advertisements once you pop don't stop right let's talk about childbirth now that I say that out loud I'm not sure it was the best transition line but let's roll with it during childbirth the size of the baby's body applies pressure to the cervix it's trying to pass through this triggers the release of the hormone oxytocin which stimulates more cervical contractions which stimulates more oxytocin which stimulates more contractions and so on we don't use positive feedback loops as often as negative feedback loops since they can end up with hormone level spiraling way past the normal ideal value but in this case the feedback loop has a natural stopping point when the baby is born then afterwards the oxytocin levels return to what they were before childbirth way more commonly our hormones are regulated by negative feedback loops where an increase in one substance eventually leads to a decrease of the same substance this makes sure hormone levels stay fairly consistent from day to day for example your body can sense when your blood is dehydrated and it'll adjust some hormones so you can conserve as much water as possible one of those involved increasing the release of days o pressin a hormone released by the pituitary gland this bump and vasopressin makes the kidneys more permeable to water by temporarily adding little water channels onto the surface of cells this moves water back into the bloodstream towards a more normal value and now that the blood is back to normal the pituitary stops pumping out as much mais au prescient that's what makes this a negative feedback loop vasopressin increase it had its effect so the body lowered its secretion one of the other hormones that uses a negative feedback loop is cortisol arguably one of the most important hormones and an example of a steroid which will come back to cortisol is often called the stress hormones since it gets released during times of stress and gives our bodies of resources for surviving the stressor like increasing sugar metabolism and puffing up our immune system this hormone is constantly in the process of its feedback loop since as you know from existing as a human in the modern world life is stressful so our bodies are constantly pumping out cortisol which begs the question how do we make a hormone well what they're made of differs from hormone to hormone most are made of proteins or peptides some from phospholipids while some are made out of cholesterol and our body cortisol is made out of cholesterol that's of what makes it a steroid hence the stero part of both words in order for cholesterol to turn into any steroid it goes through a transformation pathway it starts by converting into a molecule called pregnenolone from there it can convert into progesterone an important hormone and pregnancy and the ovulation cycle even if you personally don't ovulate progesterone still makes important compounds in your body and with a few more chemical conversions it can turn into cortisol or into androgens which include testosterone or estrogen testosterone itself can then get converted into estradiol a super important estrogen by the way that was so fascinating to me when I first learned it when I was in primary school I was taught that testosterone and estrogen were opposites but in fact they're extremely similar chemically and get made from the same ingredients so when we're talking about steroids we're talking about hormones derived from cholesterol but in everyday conversations when people talk about steroids they're probably talking about anabolic steroids hormones taken for the purpose of building big strong muscles these work by slipping into muscle cells and hooking up to an androgen receptor this stimulates the cell to produce more protein than thus bigger muscles now just because these types of steroids have been abused in the past doesn't mean that the broader class of steroid hormones themselves are harmful in fact doctors often prescribe steroids as a medication most of the time these medications have nothing to do with muscle take a group of hormones called corticosteroids the etymology gives us one away but these are any steroids that resemble cortisol these hormones have a bunch of different effects from controlling the stress response to regulating our immune system now I want to be super clear corticosteroids aren't immune cells they're chemicals that have an immune effect what makes them so effective is their ability to switch off multiple genes involved in different aspects of inflammation let's break that down inflammation is what happens when our body's mount an immune response and part of that is making certain proteins these proteins aren't just the ones that go into building muscle but include enzymes for speeding up chemical reactions or different chemical messengers involved in recruiting immune cells now our genes hold all the information needed to manufacture these proteins and certain chemicals called transcription factors can get ourselves to crank more and more of those inflammatory proteins so when corticosteroids are floating around in our blood and make their way into a cell they start a process that inhibits the effect of those transcription factors that keep inflammation going plus in larger doses they can stimulate the production of anti-inflammatory proteins because of that these steroids are also a useful treatment for reducing inflammation and conditions like arthritis or allergies that long-acting asthma inhaler yep that's a steroid to reduce inflammation in your lungs one of their other biggest use cases is acting as an immunosuppressant literally a drug that intentionally weakens your immune system wait why would you weaken your immune system on purpose well most of the time the immune system is good at identifying the things we don't want in our bodies and getting rid of them but sometimes our immune systems turn on us and attack our own tissues for instance if you watched our other series sick you've heard us talk about lupus and autoimmune disease that can cause inflammation one of the consequences of that disease could be kidney inflammation and if it gets bad enough it might lead to kidney failure which is lethal the steroid comes in handy by slowing down the production of chemicals that lead to inflammation and by tweaking how white blood cells work a doctor might prescribe an immunosuppressant steroid to someone with lupus to reduce inflammation and save their kidney and thus life so it's a trade-off increase your risk of infections from the outside world but save yourself from your own body you might also need to weaken your immune system after getting an organ transplant according to your body that new organ is a foreign object and shouldn't be there we'll learn all about how different cells in the body communicate with each other including some of those immune cells in the next episode thanks for watching human on seeker I'm Patrick Kelly