Action and effects of glucagon from alpha
So, if all this time we were dealing with
insulin, let’s move on to the opposite end
of the spectrum and we have glucagon.
Physiologic action of your alpha glucagon
would be catabolic.
Glycogen, is it storage or is it breakdown?
Glucose, is it glycolysis or gluconeogenesis?
Lipid, is it breakdown or genesis?
If it’s lipolysis, what’s the name of
It’s called hormone sensitive lipase.
I want you to come out to the picture here,
Very important that you start from the left,
go to the right.
First and foremost, you must know that glucagon
and its target receptor works through GS and
cyclic AMP, big time, because every once in
a while you’ll be given a question about
a phosphodiesterase inhibitor in which you
increase the effect of cyclic AMP thus bringing
The enzymes are activated that are necessary
for you to breakdown your lipid, enzymes are
activated so that it’s necessary to break
down your glycogen and promote gluconeogenesis.
Glucagon can never work by itself, it requires
the help of whom permissively?
Cortisol, I’ve mentioned that multiple times
and when you breakdown your lipid, I want
you to next move into circulation.
That tube to the far right represents blood
You’re going to deposit and put glucose
When you start breaking down your fat, you’re
going to have ketone bodies, that’s important…
acetoacetic acid, beta hydroxybutyric acid,
Collectively, what are those?
Keto acids, good.
And all that is going into circulation…
Now, we can move on, ketogenesis, and obviously,
if glucagon is present you have decreased
You notice, I did not put here no insulin
In your body, you could never have just one
hormone, it doesn’t work like that, okay?
You just put all these glucose into circulation…
great, but you need to get the glucose out
of circulation and put it where it needs to.
The skeletal muscle is starving right now,
remember you’re starving, this is a fasting
How do you get the glucose into your skeletal
Of course, I need insulin.
What’s the name of those transporters?
Glucose transporter 4.
Are you putting things into perspective, if
you haven’t already?
Even just a little bit of insulin goes a long,
long way and both of these are present in
your circulation, but it all depends on relative
concentration, huh, relative concentration.