A 2-day-old infant is brought to the ER suffering a seizure. Analysis of serum NH4+ reveals it to be quite high. Suspecting a urea cycle impairment the ER physician initiates hemodialysis which reduces the NH₄⁺ levels. Subsequent to the hemodialysis the infant is treated with supplemental arginine which maintains the reduction in serum NH₄⁺. The ability of arginine to render this effect stems from it's role in activating the synthesis of an activator of one of the enzymes of the urea cycle. Which of the following represents this potent activator whose synthesis is induced by arginine?

Question

Quizplus · Accepted Answer

Arginine stimulates the synthesis of N-acetylglutamate, which is an essential activator of carbamoyl phosphate synthetase I, the first enzyme in the urea cycle.

A 2-Day-Old Infant Is Brought to the ER Suffering a Seizure