Use of a semi-synthetic amino acid, 3-methoxyphenyl-L-alanine to measure amino acid absorption. pp. 304-6.

This paper describes investigations on the absorption of 3-methoxyphenyl-L-alanine (anisylalanine) in normal 
subjects, children with cystic fibrosis and in one child with Hartnup 
disease. Anisylalanine was slowly metabolised mainly to acetyl anisylalanine, and p-methoxyphenyl-pyruvic 
acid and lactic acids which were excreted. In normal adult subjects 
anisylalanine (25 mg/kg body weight) was rapidly absorbed, maximum plasma concentrations 
being obtained 0.5-1.0 hour after ingestion. Thereafter the plasma concentration declined 
exponentially. In the group of eight children with cystic fibrosis, the 
maximum plasma concentration was lower than observed in the control group, 
and was delayed. A very poor response was observed in an 
infant with Hartnup disorder. 