β‐endorphin and ACTH in plasma during attacks of common and classic migraine

Plasma levels of b‐endorphin and ACTH were measured during and outside migraine attacks in 17 patients with common migraine and 11 patients with classic migraine. Specific radioimmunoassays for b‐endorphin and ACTH were used. The b‐endorphin assay did not cross‐react with b‐lipotropin. In common migraine, median plasma b‐endorphin was 3.3 pmol/l (95% confidence limits: 2.5–4.0 pmol/1) during attacks and 2.9 (2.4–3.2) pmol/l in the headache‐free period. In classic migraine, plasma b‐endorphin was 3.2 (1.4–4.3) pmol/l during attacks and 2.4 (1.1–3.65) pmol/l outside attacks. ACTH plasma levels were 15 (10.5–20) pmol/l during and 15.7 (13.4–17) pmol/l outside attacks in common migraine. In classic migraine, plasma ACTH was 16 (7–36) pmol/l and 12.3 (8–28) pmol/l respectively. No significant differences were found between attacks and headache‐free periods in common or classic migraine. Accordingly, we could not add evidence to the theory of a dysfunction of the endogenous opioid system in migraine.