Insulin increases the entry of tryptophan into the brain by ____.
A) weakening the blood-brain barrier
B) converting tryptophan into a compound that more easily enters the brain
C) increasing metabolic activity only in those areas of the brain that use tryptophan
D) causing certain competing amino acids to enter other cells, outside the brain

Question

Quizplus · Accepted Answer

Insulin promotes the uptake of many amino acids into muscle and other tissues, but tryptophan is less affected. This reduces the competition between tryptophan and other amino acids for transport across the blood-brain barrier, effectively increasing tryptophan's entry into the brain.

Insulin Increases the Entry of Tryptophan into the Brain by ____