Intracellular messnegers: Hormones and Nitric Oxide

Okay in this video we're gonna be talking about intracellular receptor signaling, specifically focusing on hormones and nitric oxide. So first let's talk about hormones. So hormones they don't need anything special to cross the membrane, they'll just across the plasma membrane. But once they're inside the cell then they combine to an intracellular receptor. So let's focus on steroid hormones just because that's the one that your book is going to focus on and that's the one everyone's most familiar with. But steroid hormones they cross the membrane they bind to nuclear receptors. Now we've talked about nuclear receptors before. They kind of have this misleading name because they're not actually I mean they can be found in the nucleus they don't have to be found in the nucleus that can be found in the side us all. But once they're activated by binding to the hormone that is going to trigger tree transfer into the nucleus where all nuclear receptors act as transcription regulators in the nucleus. So they don't have to be present in the nucleus to just be floating around the cell doing nothing. But once they're activated they transferred to the nucleus to act in the nucleus as transcription regulators. Which is why they're called nuclear receptors. Now, hormones activate nuclear receptors when they bind to them and this binding triggers a confirmation all change and then activation. And so these are really specific molecules. So each hormone binds to a specific E. C. I. C. Nuclear receptor. And that nuclear receptor will go on to only buying certain DNA regulatory sites, not everywhere in the DNA, not every DNA regulatory site. So they're really specific towards activating certain pathways. So here we have what this looks like. Now you don't need to know any of these complex names or anything. So you can kind of just like get rid of all of them. It doesn't matter what matters is you see this hormone is diffusing across the plasma membrane once it's inside it's going to interact with this nuclear receptor even though the nuclear receptors in the cytoplasm. But once it binds it's going to cause transfer into the nucleus where that is going to interact with the D. N. A. And that's going to affect transcription and eventually translation and gene expression. So that's how hormones act. So now let's move on to nitric oxide. So nitric oxide works very similar way. It doesn't need anything special to get into the plasma membrane, it just dissolves across it. But once it's in sign it's gonna buy into an intracellular signaling protein. And so emphasizing proteins and so nitric oxide regulates a variety of different pathways. I'm not going to go over them. I'm just going to very briefly mention a couple. The first is nitric oxide is can be released by the body into blood vessels to stimulate muscle relaxation relaxation. And then the second is actually through the process of how Viagra works. So nitric oxide combined to want cyclists, which is this protein that forms cyclic GMP and this GMP goes on to exert the physical effects of Viagra. So here we have this example, here's an N. O. This gas nitric oxide it diffuses across the plasma membrane, binds to guana cyclists, which create cyclic GMP. And then you get Viagra's effects. So I'm sure many people would think that nitric oxide is a really important signaling pathway just for this function, even though has a ton of other ones that are also really important. So with that, let's now move on.

Steroid hormones signaling through binding….

• A. GTPases
• B. Nuclear receptors
• C. Kinases
• D. Phosphatases

Nitric Oxide signals by binding to which of the following molecules?

• A. GTPases
• B. Nuclear Receptors
• C. Adenyl cyclase
• D. Guanyl cyclase