2. Free fatty acids → three fatty acids Hormone-sensitive lipase is activated in response to stress hormones (eg, catecholamines, glucagon, ACTH), whereas it is inhibited by the release of insulin.

Tip

When lack of glucose, the body need new ways to generate acetyl-CoA, which then can be used in TCA cycle

• Fatty acid oxidation
• ketone body metabolism: Ketone bodies are synthesized in liver, then transported in blood to other organs for ketogenolysis, to acetyl-CoA

Regulation by fructose-2,6-bisphosphate

Main idea: Insulin & glucagon control PFK-2 & FBPase-2 → control amount of F-2,6-BP → direction towards gluconeogenesis or glycosis. Fructose bisphosphatase-2 (FBPase-2) and phosphofructokinase-2 (PFK-2) are the same bifunctional enzyme whose function is reversed by phosphorylation by protein kinase A.

• Fasting state: ↑ glucagon → ↑ cAMP → ↑ protein kinase A → ↑ FBPase-2, ↓ PFK-2, less glycolysis, more gluconeogenesis.
• Fed state: ↑ insulin → ↓ cAMP → ↓ protein kinase A → ↓ FBPase-2, ↑ PFK-2, more glycolysis, less gluconeogenesis.

Mnemonic

FaBian the Peasant (FBP) has to work hard when starving. Prince FrederricK (PFK) works only when fed.