Ultrastructural changes of the liver following L-tryptophan ingestion in rats

Oral administration of L-tryptophan at 250 mg/(kg X d) for 3 consecutive days to rats produced enlarged hepatic sinusoids and vacuolated cells, many of which contained lipid. These changes persisted for at least 2 wk. Since the hepatic metabolism of L-tryptophan is very similar in rats and humans, these data suggest that people who self-administer large doses of L-tryptophan for the purpose of decreasing sleep latency may be inducing hepatic pathology.