Unmetabolized

Unmetabolized toxines poured out of the liver upon the duodenum and probably excited at that point the secretion of hormones abnormal in character, and these stimulated abnormal secretion from the mucous glands of the stomach and bowel.

The high levels of unmetabolized phenylalanine in the urine cause a very bad musty odor, which led a Norway physician to discover PKU in 1934. The unmetabolized phenylalanine also affects the brain of the child, and unless the baby is put on a special diet of no milk, meat, or other high-protein foods, the baby is doomed to severe mental retardation.

Although the toxicity of inorganic arsenic is well established, arsenobetaine (from fish) is considered essentially nontoxic because it passes through the body unmetabolized; other organic forms such as dimethylarsenate, arsenolipids, and arsenosugars have uncertain toxicity.