Trace element concentration in the human pineal body. Activation analysis of cobalt, iron, rubidium, selenium, zinc,...

100 human pineal bodies (56 male and 44 females) were analyzed by means of instrumental neutron activation analysis for trace concentrations of cobalt, iron, rubidium, selenium, zinc, antimony and cesium. The results indicated that the measured element concentrations are not related to body-surface, age and fresh weight. Moreover, the mean absolute cobalt value from 97 pineal bodies is increased by a factor of 1.43 over the mean absolute concentration value of 257 other areas of the brain. The mean zinc content is found to be 3.7 fold higher than the mean zinc value from 269 other samples of brain. The iron values from various brain areas do not differ from those of the pineal body. Compared to other brain regions pineal selenium is increased and rubidium is decreased. Correlating the different element concentrations to each other, a positive correlation is found for selenium and ribidium, a negative correlation for cobalt and zinc. The present data suggest that the measured trace elements are somehow related to specific roles in the physiology and biochemistry of the pineal body. This is supported by the constancy of element concentration over a wide range of increasing fresh weights of the organ. It is considered that zinc, cobalt and iron are involved as constituents of enzymes in the metabolism of amino acids, peptides and proteins of the pineal body. Moreover the conspicuous high zinc content of this organ may be related to a so far undetected neurotransmitter.