Abstract:
Gyps species have been previously shown to be highly sensitive to the toxic effects of diclofenac, when present in their food sources as drug residues following use as a veterinary
medicine. Vultures exposed to diclofenac soon become depressed and die with signs of
severe visceral gout and renal damage on necropsy. The molecular mechanism behind toxicity and renal excretion of uric acid is still poorly understood. With the clinical pictures suggesting renal uric acid excretion as the target site for toxicity, as a first step the following
study was undertaken to determine the uric acid excretory pathways present in the African
white-backed vulture (Gyps africanus) (AWB), one of the species susceptible to toxicity.
Using transcriptome analysis, immunohistochemistry and functional predictions, we demonstrated that AWB makes use of the organic anion transporter 2 (OAT2) for their uric acid
excretion. RT-qPCR analysis subsequently demonstrated relatively similar expression of
the OAT2 transporter in the vulture and chicken. Lastly docking analysis, predicted that the
non-steroidal drugs induce their toxicity through an allosteric binding.
