2020A10 An infusion of 50 mL of 50% dextrose is given to a healthy 70kg adult.
Describe the possible metabolic pathways for the dextrose.

Utilisation:	Occurs if ↓insulin, ↑glucagon Aerobic: -> 36 ATP (in all nucleated cells) Anaerobic: -> 2 ATP (in all cells)
Glycolysis
Krebs cycle	->4 x NADH+ -> 2 x FADH₂ ->2 x GTP -> 4 x CO₂
Oxidative phosphorylation	-> 1x ATP -> 1 x H2O
Storage:	Occurs if ↑insulin, ↓glucagon GLUT2: constitutive GLUT4: inducible
Glycogenesis	Uptake into liver (GLUT2), skeletal muscle (GLUT4) Dose is 25g. Limit is ~50g liver, 400g skeletal muscle Can be later catabolised to yield glucose
De novo lipogenesis	Uptake into liver (GLUT2), adipose (GLUT4)
Conversion:
Lactate (Cori cycle)
Amino acids (glucose-alanine cycle)
HMP shunt	For synthesis of nucleotides (ribose)
Rapoport-Luebering shunt	Production of 2,3-DPG in RBCs
Pathology:
Urination	Renal threshold ~10mM may be exceeded if large dose Glycosuria continuous if taking SGLT2 inhibitor
Glycosylation	Chronic hyperglycaemia -> damage to proteins -> microvascular complications (nephropathy, neuropathy)