“Of the amino acids present … parenteral nutrition solutions, only tryptophan (given at a dose of 4 mM/kg) … a significant (p < 0.01) elevation of serum cholylglycine (12.8 ± 1.0 μM/liter) as determined by radioimmunoassay, compared to 4.9 ± 0.4 μM/liter in salinetreated control animals.”
“ Tryptophan injection resulted in elevated cholylglycine concentrations only at doses of 3 mM/kg/day or higher.”