PMC

Plasma kynurenine concentrations increased significantly in response to tryptophan infusion, moreso in men than in women. However, there were no differences as a function of diagnostic group or interactions of diagnosis with time. Values are given as means ± SEM.

Plasma tryptophan concentrations increased significantly over time following tryptophan infusion, moreso in men than in women. However, there were no differences as a function of diagnostic group or interactions of diagnosis with time. Values are given as means ± SEM.

ADACL energy scores decreased in CFS patients and healthy subjects after tryptophan infusion. Both patient groups had significantly lower Energy scores than controls prior to infusion. Energy scores decreased in response to tryptophan infusion in CFS patients (p = 0.002) and healthy subjects (p = 0.003), but a decrease was not evident in CFS + FM patients (p = 0.30). Minimum and maximum possible scores are 5 and 20, respectively. ADACL, activation-deactivation checklist.

Plasma prolactin response to exogenous tryptophan (120 mg/kg lean body weight) administered i.v. between 15 and 45 minutes. Among women (A), tryptophan appears to induce a greater plasma prolactin response in the CFS only group, and perhaps in CFS+FM group, than in the control group. There is no apparent difference among the men (B). All subjects exhibited a return to baseline concentration by 90-minutes postinfusion. Values are given as means ± SEM. CFS, chronic fatigue syndrome; FM, fibromyalgia.