Elevation of plasma vasopressin in spontaneous migraine.

Vasopressin is a vasoactive hormone secreted from the posterior pituitary. At low concentration its role is in regulating renal water excretion, but at higher concentrations it has a number of extrarenal actions, including effects on blood flow. To investigate the role of vasopressin in spontaneous migraine, paired samples were collected from 14 subjects (a) during an acute attack of spontaneous migraine, and (b) when symptom-free for at least seven days. During an attack, vasopressin was consistently raised (median (range) 3.5 (1.2-9.6) pg/ml v 0.5 (0.5-1.1) pg/ml, p less than 0.001). The highest vasopressin concentration occurred in the only patient who vomited. The results suggest vasopressin rises during an attack of spontaneous migraine, and this may, in part, be related to emesis. In the majority, vasopressin levels only rose sufficiently to have some renal antidiuretic effect, although in some these levels could have been sufficient to cause alteration in peripheral blood flow. Release of vasopressin may be responsible for the facial pallor and antidiuresis observed in migraine.