Detoxication definition

Williams RT. Detoxication Mechanisms. The Definitive First Complete, Comprehensive Text on Drug Metabolism. London Chapman Hall, 1959. 

It is well known that the toxicity of many elements depends on the physicochemical forms they assume. So, for instance, determining the total content of a certain element in a sample is definitely not sufficient to measure its toxicity. Selenium is a case in point in small amounts this element is essential to human health. But the transition from the necessary amount (about 70pg of selenium per day for an adult) to a toxic dose (about 800 pg of selenium per day) is relatively easy. In rats, moreover, the fatal dose of Se(IV) compounds is 3.2 mg kg 1 of body mass, whereas for dimethyl selenide it is 1600 mg kg 1 of body mass. Nonorganic selenium compounds [Se(IV) and Se(VI)] are believed to be the most toxic ones, whereas in the environment selenium occurs most commonly bound to amino acids (selenomethionine and selenocysteine). The least toxic forms seem to be the volatile methyl compounds of selenium, which are metabolites of a detoxication process. 

Miraculously, few human tragedies have definitely been traced to 2,4,5-T or TCDD, in war or peace. Further investigation indicates that environmental break-down may be largely the reason. TCDD is very unstable to sunlight when it is present as a trace contaminant in commercial pesticides (Fig. 10) (33,34), especially when applied to inert surfaces or leaves. The present lack of evidence for widespread occurrence of TCDD in the environment may be directly related to its environmental chemistry. The knowledge that the detoxication and loss occur through reductive dechlorination by the solvent also opens the way for intentional TCDD destruction or decontamination. 

Inhibition of ornithine breakdown in the liver with a favourable effect on urea synthesis (= definitive ammonia detoxication)... 

The reaction takes place in the liver and is called detoxication. This word would imply that the enzymes have a definite purpose. It is more likely that this mechanism simply exists, and that very many substances—both endogenous ones, like hormones or bilirubin, and exogenous ones, like drugs and poisons—are bound in this fashion and are excreted, independent of their toxicity and any intentions of the organism. 

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