TISSUE DISTRIBUTION OF ABSORBED HUMIC ACIDS

Distribution of humic acids (HA) in rats was studied using radioiodina ted HA injected intraperitoneally. Distribution of I-125 was also stud ied for comparison. The distribution pattern of HA differed greatly fr om that of I-125. Except in the thyroid and skin, I-125 was excreted f rom the body within 24 hours, whereas a large proportion of HA remaine d in the liver, kidney, skin, thyroid, bone and muscle. The difference in the distribution pattern and organ/serum radioactivity ratio sugge sts different kinetics for I-125 and I-125-HA. The distribution patter n of HA correlated very well with the increased prevalences of organ d iseases in the blackfoot disease endemic area, as reflected in epidemi ologic studies. It is hypothesised that HA-metal complexes are possibl e etiological factors of diseases such as goitre, hepatoma, bladder ca ncer, vascular disease and diabetes mellitus, and that free radicals a re the common causative factor.