I understand how G6P being trapped leads to the other symptoms via pathway shunting, but why is there increased glycogen? Does G6P feedback to inhibit glycogenolysis? I don't think it'd be possible to shunt the G6P to glycogen synthesis since the hypoglycemia would lead to hormonal inhibition of this. Can someone please explain? Thanks!
Why hepatomegaly in Von Gierke?
- Thread starter BR20
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G1P (from glycogen breakdown) must be converted to G6P in order to be liberated into free glucose via glucose-6-phosphatase in the liver… a deficiency in this enzyme impairs proper breakdown of glycogen, hence the reason it is increased w/ in the cell
Thanks, I guess I wasn't clear though. I understand that much. My confusion is regarding how a G6-phosphatase deficiency results in increased glycogen, since the G6P molecules have already been cleaved from glycogen. There's no problem with glycogen breakdown, the problem is managing the breakdown product. And since there's hypoglycemia leading to increased glucagon, that G6P can't be added back onto the glycogen chain. In fact, you'd think the opposite would happen as the hypoglycemic state lead to increased glycogen breakdown, leading to less glycogen in the liver (every book I have says its increased) but with accumulation of G6P. So, is the hepatomegaly actually due to accumulated G6P and not glycogen, or does the accumulation of G6P somehow feedback to inhibit one of the glycolytic enzymes?
