The production of histamine from histidine by ultra-violet light and the absorption spectra of these substances

Abstract

Experiments were made on the formation by the ultra-violet irradiation of histidine of a substance pharmacologically identified as histamine. The results confirm Ellinger''s previous work in many respects, but differ in showing that wavelengths shorter than 265 mu are far more active in such formation than longer wave-lengths. The ultra-violet absorption curves of pure histidine dichloride, and of histamine phosphate show little absorption, except for wave-lengths shorter than 240 mu. These facts do not support the suggestion that the erythema following irradiation of the skin is due to the formation of histamine from histidine by the simple chemical process which may be demonstrated outside the body.