Glucagon: Functions

00:02 Now what does glucagon do? The functions of glucagon are primarily it's break down glycogen.

00:11 So there's a lot of glycogen stored in places like the liver.

00:14 And this is one of the stimuli to have it break down.

00:18 It's done by activating the enzymes which break down glycogen and inhibiting the enzymes that form new glycogen.

00:30 The last thing that it does is stimulates the enzymes which do the final break down product going from glucose 6-phosphate to glucose.

00:42 Then the glucose is transported out of the cell to transporter.

00:49 Now that is the process of breaking down glycogen, releasing glycogen out in the circulation.

00:56 So this should remind you of the process of --we're not building things here with glucagon.

01:02 We're breaking down glycogen so we can use that blood glucose.

01:07 What else does it stimulate.

01:10 The enzymes associated with gluconeogenesis.

01:13 So gluconeogenesis is the process of making new glucose out of things that weren't glucose to start with like amino acids.

01:24 It also stimulates the enzymes associated with lipolysis.

01:27 So there you have fat.

01:30 You can break it down into more simple form and release free fatty acids into the circulation.

01:36 And finally it stimulates ketogenesis which is the formation of ketone bodies.

01:42 So between all four of these processes, you should think of --okay, we're breaking down glycogen so that we can get more blood glucose.

01:51 We're making new blood glucose.

01:53 We're breaking down fats.

01:54 So the free fatty acids are in the circulation.

01:57 And we're forming ketone bodies.

01:59 All of those can be used as energy substrates for different tissues of the body.

02:05 So glucagon is really preparing you so make sure you can use energy that's been stored in the body.

02:13 So you can use it for increase in metabolism.

02:18 So let's now look at this in more of a systemic effect.

02:22 The systemic view always let's us take a step back, point to the various tissues, see where the different molecules are going.

02:31 And as you're studying for your test, this is a very important thing to do, it's easy to get lost in the leaves of a tree without taking a step back to look at the branches and how their shape is.

02:43 So that is this kind of a process.

02:45 So we know we have the release of blood glucose.

02:50 Usually comes from the liver by breaking down glycogen through a number of steps and then finally releasing blood glucose.

03:01 Fatty acids are also broken down through lipolysis and moved out of adipose tissue into the circulation.

03:11 Those fatty acids are also form the basis of backdrop for ketoacids.

03:19 So here we've got increases in glucose, fatty acids and ketoacids.

03:25 All help us do what, increase our metabolism.

03:30 Because we're responding to some sort of stressful environment.