Term
| what are the main Gluconeogenic precursors |
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Definition
| Lactate, pyruvate, amino acids and glycerol |
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Term
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Definition
| results from a defect in glucose 6-phosphatase |
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Term
| What are the enzymes that catalyze the 3 bypass steps of gluconeogenesis? |
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Definition
1. pyruvate to phosphoenolpyruvate (PEP), occurs in two steps (catalyzed by pyruvate carboxylase and PEPCK (PEP carboxykinase)).
2. Fructose 1,6-bisphosphatase
3. glucose 6-phosphatase |
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Term
| What are the regulators of pyruvate carboxylase and PEPCK |
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Definition
Acetyl CoA activates pyruvate carboxylase
expression of PEPCK is induced by the glucagon and epinephrine signaling pathways (activated PKA phosphorylates and activates a transcription factor)
and the glucocorticoid, cortisol (a steroid hormone that can diffuse into cells, bind and activate its
nuclear hormone receptor). PEPCK expression is normally repressed by insulin signaling |
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Term
| What regulates Fructose 1,6-bisphosphatase? |
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Definition
opposite of PFK.
Citrate activates it.
AMP and fructose-2,6 bisphosphate deactivate it. |
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Term
| Where is Glucose 6-phosphatase found and how is it regulated? |
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Definition
found in hepatocytes and renal cells, not muscle or brain. It is
transcriptionally regulated in the same way as PEPCK. |
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Term
| How does excess ethanol and fasting lead to hypoglycemia? |
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Definition
| oxidation of Et-OH leads to excess NADH, which pushes pyruvate to lactate inhibiting gluconeogenesis and causing lactic acidosis |
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