Name three non-carbohydrate carbon sources for hepatic gluconeogenesis.

Study for the Biochemistry Module 6 Exam. Study with flashcards and multiple choice questions; each question includes hints and explanations. Gear up to ace your test!

The key idea is that hepatic gluconeogenesis uses carbon skeletons from non-carbohydrate sources to build glucose. The three classic substrates that supply carbon in this way are lactate, glycerol, and glucogenic amino acids. Lactate, produced by muscles during anaerobic metabolism, is carried to the liver and converted back to pyruvate, which is then funneled into the gluconeogenic pathway to form glucose. Glycerol, released from fat breakdown, is converted to glycerol-3-phosphate and then to DHAP, entering the pathway as a triose phosphate that eventually becomes glucose. Glucogenic amino acids can be deaminated to yield pyruvate or various TCA cycle intermediates (like oxaloacetate, α-ketoglutarate, succinyl-CoA, or fumarate), all of which feed into gluconeogenesis to produce glucose. These substrates provide carbon for glucose production, whereas substrates like certain fats or ketone bodies cannot be converted into glucose in humans, and intermediates like oxaloacetate are part of the pathway rather than standalone carbon sources.