Insulin secretion in migraine: influence on the blood levels of tryptophan.

The blood levels of free tryptophan, glucose and insulin were determined in different groups of patients suffering from headache, initially and after a glucose tolerance and a tolbutamide tolerance test. The control group consisted of subjects without neurological or psychiatric disturbance. A sharp drop of blood tryptophan levels was observed in migraine patients during the tolbutamide tolerance. Migraine attacks may be induced in certain subjects by a disturbance of 5-hydroxytryptamine turnover.