Gluconeogenesis

All of the following are gluconeogenic substrates that can be converted to glucose-6-phosphate EXCEPT:

A 52-year-old man with poorly controlled type 2 diabetes mellitus and chronic liver disease presents with fasting blood glucose of 280 mg/dL despite metformin therapy. All of the following mechanisms contribute to hyperglycemia in this patient EXCEPT:

A 32-year-old woman from rural Maharashtra presents to the emergency department with a 3-day history of severe vomiting and abdominal pain following acute gastroenteritis. On examination, she is lethargic, with blood pressure 88/54 mmHg and heart rate 112/min. Laboratory investigations reveal: - Blood glucose: 42 mg/dL - Serum bicarbonate: 12 mEq/L - Serum lactate: 8.2 mmol/L (normal <2) - Serum β-hydroxybutyrate: 6.8 mmol/L - Liver function tests: normal - Serum creatinine: 1.8 mg/dL Which enzyme deficiency would most directly explain the failure of gluconeogenesis in this clinical scenario?

Pyruvate carboxylase, the first enzyme of gluconeogenesis, requires which cofactor and is located in which cellular compartment?

A 3-year-old child presents with severe hypoglycemia (blood glucose 28 mg/dL) and hepatomegaly during a 6-hour fast. The child is lethargic and has seizure-like activity. Serum lactate is elevated at 8 mmol/L (normal <2). The parents report recurrent episodes after fasting or illness. Which investigation would best confirm a defect in gluconeogenesis?