MS-1673

MS-1673

A 56-year-old woman complains of aching pain in her legs and persistent fatigue over the last two months. Her blood is tested, and the following results are obtained:

– Hb: 135 g/L (115 – 160)
– Serum ferritin: 25 µg/l (10 – 300)
– Folate: 7.0 ng/ml (>4.0)
– B12: 525 pg/ml (180 – 1000)
– Na+: 141 mmol/L (135 – 145)
– K+: 4.1 mmol/L (3.5 – 5.0)
– Creatinine: 86 µmol/L (55 – 120)
– CRP: 1 mg/L (< 5)
– Corrected serum Ca2+: 2.35 mmol/L (2.25-2.5)
– ALP: 85 U/L (30 – 130)
– Vitamin D: 17 nmol/L (>50)
– TSH: 0.31 mIU/L (0.27 – 4.20)
– HbA1c: 38 mmol/mol (<48) Based on these results, the GP prescribes medication to address the underlying cause of her fatigue. Where does the conversion of this medication into its biologically active form take place?