In this video, we're going to examine two processes. Glycogenesis, that is the formation of glycogen from glucose monomers and gly glycogenolyis which is the breakdown of glycogen. Now in glycogenesis this is going to occur when the glucose amounts in circulation are far exceeding what we need for ATP production. So this is a step to sort of store energy from uh the foods we've eaten and if we've have sort of this glut of uh nutrients available. So this process is going to occur mostly in the liver and the skeletal muscle. And when insulin is around uh and other cells, your body cells are using glucose as an energy source, usually that same insulin will signal the hpatoytes, the liver cells to process that glucose as a longer form of storage in glycogen. Now there are multiple steps. We're not going to worry too much about the enzymes involved here. Um, glucose 6 phosphate is actually going to be a very important intermediate. So, this is the first step. We'll write that down. This is the first step in glycolysis. So, remember this was during that investment phase. So there's a series of enzymes that are going to convert glucose 6 phosphate and ultimately chain them together. Really the important enzyme for glycogenesis is going to be located right here. Glycogen synthes for glycogenolyis. This is going to be the breakdown of glycogen. And the enzyme involved here is going to be called glycogen phosphorase. Now this is going to occur in response to very low blood sugar. So usually it can be stimulated by the hormone glucagon. So this is again going to occur in the liver. So the hippatocytes but some kidney and some intestinal cells can also kick in. Interestingly enough, glucagon is not the only hormone that can stimulate this process. Um, cortisol, the stress hormone, can also uh initiate this process where you're breaking down uh glycogen to release glucose during periods of stress. So keep in mind that complex carbohydrates have more chemical bonds. Therefore, there's more energy stored in it. Uh sometimes this glycogen aside from the liver can be stored in the muscle. So this can be more effective than a high protein diet, right? We figure, oh, a high protein diet is diet is needed for intense muscle activity. Not really the case, right? The proteins aren't going to have more energy than carbohydrates. So, this is why carbohydrate loading is a little bit more effective. Now, that's not to say that if you have any kind of muscle activity, you don't need protein. Uh, a high protein meal is great if you want to build muscle, but building muscle takes time. So, it's not really effective for the short term if you want endurance for that intense muscle activity that's coming up. So, with carbohydrate loading, the diet is going to be rich in carbohydrates for the preceding 3 or 4 days. Uh, and that's going to be coincident with lower activity. So you're not using up those resources. And so your body is going to adjust because there's a buildup of this carbohydrate in circulation. And so the liver cells and the muscle cells will then begin to transform that glucose into glycogen to that uh short shorter term storage versus atapost tissue. So, the results are going to be an improved performance and endurance because you have a greater availability of ready energy. It's much easier to break down glycogen, right? Remove those glucoses than it is to break down lipids. And we'll talk about lipids in a future video. Now, the last topic I want to touch on is this concept of gluconneogenesis. that is the formation of new glucose. Now obviously the breakdown of glycogen is one form of reconstituting glucose. Uh but there are many other ways we can uh break down and transform glycerol. we can transform various amino acids and sort of reverse engineer via the intermediates in glycolysis and generate glucose. So this is going to occur when blood glucose levels drop. Uh this is helping to protect us against the effects of hypoglycemia. Keep in mind that there are metabolic tissues that are solely dependent on glucose levels like your nervous system. This is especially going to be important for the nervous system because the nervous cells aren't breaking down atapose and amino acids for energy. So they need a constant supply of glucose and they're always going to be metabolically active, right? Uh so gluconneogenesis uh can be promoted by certain hormones. Uh we already mentioned the stress hormone cortisol uh as well as uh the antagonistic hormone to insulin glucagon. But lastly, there's a third hormone, epinephrine, that can be activated during these effects of hypoglycemia. And what's really interesting about these hormones is they do not have an additive effect. Instead, they have what we refer to as a synergistic effect. Now the the difference is imagine that cortisol raised your glucose levels by one. I'm not even putting units here, right? Glucagon raises it by one. Epinephrine raises it by one. So if I just had one or the other or the other, glucose levels would only rise by one. Okay. An additive effect would be if I had all of these hormones that I would have now three glucose. With a synergistic effect, you have a greater effect than the additive effect. So if I have all three hormones, instead of having a plus three effect, I might have a plus five effect. So the regulation of glucose is going to be sort of in this synergistic manner, right? the the glucose levels in circulation.