In acute intermittent porphyria management, which treatment suppresses ALA synthase activity?

In acute intermittent porphyria management, which treatment suppresses ALA synthase activity?

• A. Liberal hydration
• B. Glucose supplementation
• C. Heme arginate
• D. Prevention of hypothermia

Answer: (C)

Heme synthesis in the liver is controlled by feedback: when heme levels rise, ALA synthase 1 (the first and rate-limiting step) is downregulated to curb production of upstream toxic precursors. In acute intermittent porphyria, providing exogenous heme directly taps into this feedback loop, suppressing ALAS1 activity quickly and markedly. Heme arginate delivers that heme surge, lowering the production of ALA and porphyrin precursors and thus alleviating neurovisceral symptoms. While glucose can help reduce ALAS1 activity to some extent by insulin-mediated effects, and good hydration supports overall care, neither matches the direct and rapid suppression achieved by heme arginate. Prevention of hypothermia doesn’t impact the ALAS1 regulation pathway.

Heme synthesis in the liver is controlled by feedback: when heme levels rise, ALA synthase 1 (the first and rate-limiting step) is downregulated to curb production of upstream toxic precursors. In acute intermittent porphyria, providing exogenous heme directly taps into this feedback loop, suppressing ALAS1 activity quickly and markedly. Heme arginate delivers that heme surge, lowering the production of ALA and porphyrin precursors and thus alleviating neurovisceral symptoms. While glucose can help reduce ALAS1 activity to some extent by insulin-mediated effects, and good hydration supports overall care, neither matches the direct and rapid suppression achieved by heme arginate. Prevention of hypothermia doesn’t impact the ALAS1 regulation pathway.