Effect of light and darkness on pineal hydroxyindole-O-methyl transferase (HIOMT) in Japanese quail

Abstract

The optimal incubation temperature for assay of the melatonin-forming enzyme, hydroxyindole-O-methyl transferase (HIOMT), of the Japanese quail pineal, was determined to be 47° C. In adult quail, HIOMT activity was high in continuous light and in the light phase of 12 L 12 D and 12 D 12 L , and was low in continuous darkness and in the dark phase of 12 L 12 D and 12 D 12 L . Age of the bird and length of the lighting treatment seemed to be important factors in demonstrating this effect of light and darkness on HIOMT activity.