 Hi, welcome to Physiology Open. For understanding the functions of glucocorticoids or cortisol which is the major glucocorticoid in body, you should realize that glucocorticoids are the hormones whose concentration rises in its stress and these hormones do all things to help the body deal with its stress. You will be able to correlate better especially if you take an example of an animal. So suppose when an animal is injured, which is obviously a state of stress, what are the things which should happen in the body? Since during this time, the animal will not be in a state to search or hunt for its food, its blood glucose levels should be maintained, isn't it? Especially for the neurons, since other tissues can even use fats and amino acids at fuel. Secondly, it should help in repair of the injured area. So with injury there will be inflammation, so it should keep the immune system in check so that it does not overdo its job and spoil everything. So how does it carry out all these functions? For maintaining blood glucose levels, glucocorticoids should stimulate metabolic reactions which release glucose in blood. Simultaneously, they should shift the metabolic systems of tissues other than neurons from utilization of glucose for energy to utilization of fatty acids and amino acids as fuel. This is known as glucose-pairing effect of corticosteroids, that is they are sparing glucose for neurons since it is the only fuel which they use. So in factual terms, glucocorticoids increase the gluconeogenesis in liver to provide a regular supply of glucose. This is the utilization of glucose by skeletal muscles by preventing its uptake. This is an anti-insulin action, since insulin facilitates glucose uptake by muscles. Then glucocorticoids increase proteolysis, proteolysis means a breakdown of proteins. This releases amino acids and these amino acids can be used for gluconeogenesis. Also they can be used for repair, say in case of injury. So basically synthesis of proteins is inhibited and its breakdown takes place. In short, you cannot build your muscles if you are under stress and your glucocorticoids are consistently high. Glucocorticoids also increase lipolysis in a deposed tissue causing breakdown of triglycerides and thus releasing free fatty acids and glycerol. Free fatty acids are used as fuel by tissues while glycerol is used for gluconeogenesis. Now let's come to next function. For checking the immune system, glucocorticoids exert some anti-inflammatory action. Basically they act on almost every step of inflammation. So this diagram in brief shows some of the steps of immune response. Glucocorticoids reduce inflammation by stabilizing the membrane of lysosomes. The contents of lysosomes are pro-inflammatory, so when lysosomes release its contents it causes increased inflammation. So the stabilization of the membrane helps in restricting inflammation. Then they decrease the expression of addition molecules and endothelial cells, thus decreasing the recruitment of WVCs to the site of inflammation. Then they decrease the release of cytokines by WVCs, which are responsible for further recruitment and activation of WVCs. Now since many cytokines lead to proliferation of fibroblasts which synthesize collagen, this also prevents excess car formation. And glucocorticoids also inhibit production of antibodies by bilemphocytes. Not only that, they can also induce apoptosis of WVCs. Then in various immune cells, arachidonic acid is released from membrane, from which prostaglandins are synthesized in presence of cyclooxygenase enzyme. Now these prostaglandins activate many steps in inflammation. This increases the synthesis of lipocortin while inhibits the synthesis of cyclooxygenase enzyme. This lipocortin actually inhibits the enzyme phospholipase A2, which is the one which actually releases arachidonic acid from the membrane. So due to increased synthesis of lipocortin, less arachidonic acid is released and due to inhibition of cyclooxygenase enzyme, less prostaglandins are produced from whatever arachidonic acid is there. So this again limits the inflammation. In fact, for the check on immune system, a negative feedback loop operates. WVCs themselves secrete ACTH, which increases cortisol, that is glucocorticoids. Also the cytokines, which are released by WVCs, act on hypothylamic pituitary axis increasing the release of cortisol. And the release cortisol in turn inhibits the actions of WVCs, so this is a negative feedback loop, isn't it? Apart from this, glucocorticoids have many permissive actions also, that is presence of glucocorticoids is needed for the action of other hormones like catecholamines and glucagon. The release of free fatty acid is the major action of catecholamines for which glucocorticoids are required. Also in acute stress, they are essential to maintain blood pressure. Catecholamines cause vasoconstriction for which glucocorticoids are required. So these are the functions of glucocorticoids in a nutshell. Well, hopefully you have understood the fundamentals of functions of glucocorticoids. Thanks for watching the video, if you liked it, do like and share the video and don't forget to subscribe to the channel Physiology Open, thank you.