ABSTRACT
This chapter reviews the effects of chemicals on the heme biosynthetic pathway, and the use of porphyrins as “nondestructive” indicators of exposure of wildlife to environmental pollutants will be advocated. It aims to encourage environmental biologists to investigate porphyrins as biomarkers of exposure more extensively than they have done in the past. Porphyrins are tetrapyrrolic pigments widely distributed in nature. Although the property of synthesizing porphyrins and heme is shared by all animal cells, quantitatively the most significant contribution to their formation is afforded in the body by the erythropoietic system, the liver, and — to a lesser extent — the kidney. There are conditions, however, some genetically determined and others induced by exposure to environmental chemicals, where these control mechanisms break down. The study of the fecal excretion of porphyrins, as a measure of the amount of porphyrins made in the body, is therefore subject to several potential sources of error.
