ABSTRACT
Several highly mutagenic compounds have been isolated from the crust of fried or broiled meat and fish. All these mutagens are heterocyclic primary amines which can also be produced by amino acid pyrolyzation or by heating model systems composed of amino acids, creatine, and sugar. The binding of heterocyclic amines to fibers or other fecal material probably results in lower bioavailability of the compounds. Heterocyclic amines have been detected in dialysis fluid of kidney patients. Heterocyclic amines seem to be rapidly and extensively metabolized. The bile and urine of humans naturally exposed to very low doses of heterocyclic amines via food consumption contained very small amounts of unchanged heterocyclic amines. The liver is an important site for metabolic transformation, but also other tissues such as intestines, kidney, lung, and skin metabolize heterocyclic amines. Heterocyclic amines are metabolically activated through hydroxylation of the exocyclic amino group.
