Identification of interspecific differences in phase II reactions: determination of metabolites in the urine of 16 mammalian species exposed to environmental pyrene.

The research investigates how different mammal species metabolize pyrene, a potentially harmful environmental compound. This study identified certain species-specific metabolic patterns, with implications for monitoring environmental pollution.

Objective of the research

• This research aimed to identify the interspecific metabolic differences across 16 mammal species in their response to the environmental pollutant, pyrene. Pyrene is a polycyclic aromatic hydrocarbon (PAH) with potential for carcinogenic and endocrine-disruptive effects, necessitating the study of its metabolism in various animals, including livestock, pets, and wildlife.

Methods

• The authors collected urine samples from a variety of mammals, including deer, cattle, pigs, horses, humans, cats, ferrets, and rabbits. The urine was analyzed for metabolites of pyrene, particularly focusing on phase II conjugated metabolites to show how different species metabolize the compound.

Key Findings

• Significant interspecies differences were identified in the concentration and composition of urinary pyrene metabolites.
• Glucuronide conjugates were the dominant metabolites found in many species, such as deer, cattle, pigs, horses, and humans – indicating that these species metabolize pyrene in a similar manner.
• Contrarily, glucuronide conjugates were not present in ferret urine, which was surprising given that the gene responsible for this metabolic pathway in ferrets (UGT 1A6) is not a pseudogene.
• The urine of cats, ferrets, and rabbits primarily contained sulfate conjugates, suggesting they metabolize pyrene differently. Additionally, pigs, known to have limited aryl sulfotransferase activity, were found to have sulfate conjugates in their urine, showing an active capability to sulfate 1-hydroxypyrene in pig liver.

Implications

• The observed interspecific differences in the metabolism of an environmental pollutant has implications for assessing species-specific sensitivities and responses to xenobiotics or foreign substances in the body.
• The research carries significant potential for biomonitoring environmental pollution, meaning that by understanding how different species metabolize pollutants, we may identify the species that are more sensitive to certain pollutants, and better design and monitor interventions.