Incretin Hormones: Production and Physiological Impact

00:00 digestion. Let's start this portion with a quick review.

00:03 Remember, the hormones GLP-1 and GIP are produced by specialized cells in the intestines. Now, specifically, the L cells produce GLP-1 while the K cells produce GIP.

00:14 It's really important that you understand these hormones because they play a vital role in blood sugar regulation.

00:21 So let's get specific on where each of these incretin hormones are made.

00:26 GLP-1 are created by special cells in actually three areas: the intestines, the pancreas, and the brain.

00:34 Now, to be honest, the majority of GLP-1 is produced by in the intestine by enteroendocrine cells called L cells.

00:42 So these L cells are distributed throughout the small and the large intestine with the highest concentrations in the ileum and the colon.

00:50 Now the other two places where GLP is made is the pancreas and the brain, but not nearly as much as in the intestines.

00:58 So there's a small amount of GLP-1 produced by a subset of the pancreatic alpha cells. And in the brain, GLP-1 is produced by neurons in the nucleus tractus solitarius, or the NTS, that's part of the brainstem and in the hypothalamus.

01:15 The second hormone is GIP.

01:18 Now, the primary site of GIP production in the body is the small intestine.

01:23 GIP is produced by K cells in the upper small intestine, with the highest concentrations in the duodenum and jejunum.

01:31 Now, keeping in mind it really does matter that you understand where these hormones GLP-1 and GIPs are produced, because you're going to gain a better understanding of how these medications work that mimic these hormones, and what they can do to support the treatment for obesity and type two diabetes by both regulating blood glucose and decreasing appetite.

01:54 Now, incretin hormones are important chemical messengers.

01:57 We're all pretty much established in that.

01:59 And they work in our digestive system.

02:01 They help us regulate blood sugar levels and appetite.

02:04 So just a quick review.

02:06 We eat the food. The specialized cells in our intestines release these hormones and they release them into the bloodstream.

02:13 Now this is triggered when the food hits your digestive tract, the endogenous hormones or the hormones that are made by my body, GLP-1 and GIP carry signals to multiple organs, particularly the pancreas.

02:27 How does the pancreas respond? Great. If you answered by releasing insulin, you got it.

02:33 You're tracking right with us.

02:35 Now remember, when you release insulin, that's what helps open the pathway so it can move sugar from the blood into the cells where it's used for energy.

02:43 And because the glucose moves from the bloodstream into the cells, this lowers the level of glucose in the blood.

02:51 Have you ever wondered why blood glucose control matters? I mean, we know it's all good, but why exactly is that? Well, here's why. Consistently normal blood sugar control helps maintain insulin sensitivity.

03:05 Now, that means you have insulin and your body can use it in insulin resistant insulin available.

03:13 But the body just can't seem to use it to get that sugar from out of the bloodstream and into the cell. So with consistency in maintaining a normal blood sugar, this will help maintain insulin sensitivity.

03:28 And that's what allows your body to effectively respond to the insulin and get that glucose into the cell to use for energy.

03:36 On the other hand, poor blood sugar control can result in organ damage and can also contribute to insulin resistance.

03:43 And we talked about that.

03:44 No good. So when the body is experiencing insulin resistance, the cells just become less responsive to the effects.

03:52 And what we want from insulin.

03:54 Now, to make matters worse, insulin resistance is also associated with difficulty managing weight and can actually promote fat storage.

04:03 Now, lifestyle changes that improve blood sugar control can absolutely help improve insulin sensitivity, but it's important for you to note that reversing insulin resistance is possible, but it's also complex and depends on many, many factors. Now, those two main incretin hormones that play the key roles in processing and controlling blood sugar remember that's GLP-1 and GIP. Those are the hormones that work together and are what help maintain healthy blood sugar levels in three main ways.

04:36 It's obvious why these medications were key players when they started being used for the treatment of diabetes type two.

04:44 Because what do they do? First, they stimulate that pancreas.

04:47 It makes more insulin.

04:48 And when the blood sugar levels are rising, that pancreas knows it's time to put out the insulin. Now they also slow down that rate that food moves through your stomach, which helps prevent those sudden spikes in blood sugar.

05:02 Now, as you talk about the adverse effects, that's where some of the nausea and GI problems are going to come from.

05:07 They slow down the rate of food moving through the body.

05:11 That can sometimes be problematic.

05:13 So we keep reinforcing these concepts because you're studying with us. So by the time you finish our series, you should have a very solid understanding and be ready for your exams.

05:26 So they stimulate the pancreas to produce more insulin and slow down the rate at food moves through.

05:32 And the third one. They reduce the appetite.

05:35 And here's the part that people that are receiving these medications for the treatment of obesity are so excited about because these ingredients, the ones in our body, and particularly the medications that are also given the ingredients that are synthetic ingredients, they reduce the appetite by sending signals to the brain that help us feel full and satisfied after meals.

05:59 You'll hear clients describe it as food noise, so much lower or almost completely gone when they get to use these medications.