Lipid Hormone Signaling

Alright. So here we're going to briefly revisit our map of the lesson on bio signaling pathways, which is down below right here. And of course, we know that we've been exploring this map by following the left most branches first and already in our previous lesson videos. We've covered G coupled protein receptors or GPC ours. And we've talked about all of these different branches in our previous lesson videos. And we've also talked about the receptor, tyrosine, kindnesses or arty ks. And we've covered the insulin and insulin receptor and talked about two different insulin rtk signaling pathways one on glucose metabolism that included P three K, pip three PKB and PDK one and another insulin RTK signaling pathway. That was as a growth factor that included both the wrasse pathway and the map K pathway, the rats pathway, which included grb two sauce and wrasse, and the map K pathway, which included Wrath one MEC and ERC. And we also discussed in our previous lesson videos a variation oven rtk, which was the jak stat signaling pathway. And so now that we've covered all of the GPC, ours and all of the r t K is that we're going to cover here. In our course, we can finally move on to the final branch of our bio signaling map, which is over here, and we're going to discuss lipid hormone signaling. So let's get started with that. So here we're going to begin our introduction to lipid hormone signaling. And so recall from our previous lesson videos that hormones are really just defined as signaling molecules that are going to be released by a cell or gland that can travel and effect. Distant cells in other areas of the body now moving forward in our course were mainly going to talk about two main types of hormones. Peregrine hormones and endocrine hormones. Now, peregrine hormones are going to travel short distances, and Onley affect sales that air nearby in the vicinity of the synthesis of the peregrine hormone, whereas endocrine hormones, on the other hand, are released into the bloodstream. And we know that our bloodstream pretty much extends to all of the cells in our body. And so once endocrine hormones are released into the bloodstream, they could pretty much travel through the bloodstream long distances to their target cell. And so if we take a look at our image down below, notice that we're going to distinguish between the top half of the image and the bottom half of the image. And so the top half is showing us the peregrine hormones. And again, the peregrine hormones are going to travel short distances, whereas the bottom half of the image down below is showing us the endocrine hormones, which again are going to travel. Long distances in effect, target cells at a greater distance in different areas of the body. And so peregrine hormones again they travel short distances and Onley affect nearby cells in the area of its synthesis. And so notice over here on the left, we're showing you a signaling cell that's creating this green para Quran hormone here, and it's binding to the receptors on this specific target cell. And so the target cell is expressing the correct receptor to respond to the signals that the signaling cells creating. And this is going to elicit a bio signaling pathway in the target cell that leads to a cell response. But really the main difference. Here's peregrine hormones are traveling short distances here, affecting a neighboring target Self. Now, if we take a look at the endocrine hormone down below. In the bottom half again, it's going to travel long distances, and this is because the signaling cell that's creating the endocrine hormone is going to be Oh is going to be secrete in the endocrine hormone into the bloodstream. And, of course, once it's in the blood stream, it could defuse long, long distances to completely different areas of the body and affect target cells in different areas of the body. And so here we have a target cell that's expressing the correct receptor here to respond to the endocrine hormone, and that's going to illicit a bio signaling pathway in the target cell that leads to a cell response. But again, the main difference here is Perricone. Hormones travel short distances, whereas endocrine hormones travel long distances because they're secreted into the blood stream. And so this year it concludes our introduction to hormone, specifically peregrine and endocrine hormones, and as we move along in our course, will be able to talk more mawr about lipid hormone signaling. And so I'll see you guys in our next video

So here in this video, we're going to continue to talk about lipid hormone signaling. More specifically, we're going to focus on how lipid hormones are capable of diffusing straight through the plasma membrane. Now, it's important to note is that most hormones are either proteins such as insulin, amino acid derivatives such as epinephrine or steroids such as estrogen. And so recall that way back in some of our previous lesson videos, we actually did cover steroid hormones when we talked about lipids, and so we know that these steroid hormones are really just defined as these hydrophobic molecules that are derived from cholesterol. Now, the hydrophobic nature of these lipid steroid hormones is really, really important because this allows lipid hormones to commonly bind to interest cellular receptors. And these intracellular receptors are going to be found on the inside of cells, either in the cytoplasm or in the nucleus. And this is very, very different from the non lipid hormones that we talked about in our previous lesson videos, because non lipid hormones don't really have this hydrophobic nature, and so they're going to bind exclusively to extra cellular portions of receptors and the plasma membrane and So if we take a look at our image down below, notice that the non lipid hormones that we talked about in our previous lesson videos such as epinephrine and insulin are going to bind specifically to the extra cellular portions of receptors that air embedded in the cells plasma membrane. But the non lipid hormones are not capable of diffusing directly through the plasma membrane or into the nuclear membrane on again. That's because the nature of none lipid hormones eyes not really hydrophobic enough toe allow them to defuse directly through plasma membranes. However, when it comes to lipid hormones, on the other hand, such as estrogen notice that they are capable of diffusing directly through the plasma membrane to have a direct effect on the metabolic response. Or they could diffuse through the plasma membrane and through the nuclear membrane toe, have a direct effect on gene expression, uh, responses, whereas again the non lipid hormones have to bind to the extra cellular portions and they have to go through signal transaction in order to have their effect on metabolic response or gene expression, and so notice that some lipid hormones can also have the capability of binding toe extra cellular portions of receptors as well, and they can also lead to signal transaction in some cases as well. That leads to metabolic responses or gene expression responses, but you can see how lipid hormones can be diverse. They combined to extra cellular portions they can diffuse directly through the plasma membrane. Or they can diffuse through the plasma member and through the nuclear membrane. And so, ah, scientist or a researcher needs to be really, really aware of the type of hormone that they're working with, because if they're working with non lipid hormones, then they know for sure that they're going to bind toe extra cellular portions of receptors. But if they're working with lipid hormones, then they need to be aware that lipid hormones are capable of either binding toe, extra cellular portions of receptors. But they're also capable of diffusing directly through plasma membranes and nuclear membrane so well as well toe have amore direct effect on metabolic response and gene expression responses. And so this year concludes our lesson on how lipid hormones have the ability to diffuse through plasma membranes unlike non lipid hormones, and so we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you guys in our next video.