The pineal gland of the mole (Talpa europaea, L.). V) Activity of hydroxyindole-O-methyl transferase (HIOMT) in the formation of melatonin/5-methoxytryptophol in the eyes and the pineal gland

Using a method in which no substrate is added, the capacity of HIOMT to synthesize melatonin and/or 5-methoxytryptophol has been determined in the pineal and the eyes of the mole, a mammal having an atrophied visual system. In all animals studied, the activity of HIOMT in both eyes taken together was 2-10 times higher than in the pineal. The results prove that the pineal is not the only, and not always the most important, source of methoxyindoles.