Hepatic, Renal, and Adrenal Toxicology

Kupffer cell structure in the juvenile Nile crocodile,Crocodylus niloticus

“…Some authors differentiate between Kupffer cells and melanomacrophages which have also been referred to as “pigment cells” or “specialized Kupffer cells” when they contain melanosomes (Storch et al, ; Schaffner, ; McClellan‐Green et al, ; Jacobson, ). The juvenile Nile crocodile liver contained numerous but isolated pigmented Kupffer cells as opposed to the collections of specialized Kupffer cells and pigment cells that had been noted in other reptiles (Hack and Helmy, ; Henninger, ; Henninger and Beresford, ; McClellan‐Green et al, ; Jacobson, ). Storch () distinguished between Kupffer cells and pigment cells in the West African crocodile describing them as two separate cell populations.…”

“…Two pigments, namely melanin and hemosiderin, coexisted in the phagosomes of the Kupffer cells of the Nile crocodile. Hemosiderin is derived from the breakdown of haemoglobin and catalyses the formation of free superoxide radicals that are trapped by melanin (Beresford, ; Sichel et al, ; McClellan‐Green et al, ). Kupffer cells of reptiles and amphibians are able to synthesize melanin (Henninger and Beresford, ; Kalashnikova ; Corsaro et al, ; Sichel et al, ) which is deposited in melanosomes.…”

“…Although some studies have been done on the livers of nonmammalian vertebrates (Schaffner, ; McClellan‐Green et al, ; Jacobson, ), there is a lack of information regarding the fine structural morphology of Kupffer cells. Literature describing this important component of the liver in crocodiles is limited to the West African crocodile (Storch et al, ), with information on the Kupffer cells of the Nile crocodile being nonexistent.…”

Technique for the collection of clear urine from the Nile crocodile (<i>Crocodylus niloticus</i>)

“…Urine could therefore provide an additional or alternative sample that may be better than plasma for some analyses, such as in the detection of metabolised and water soluble pollutants and drugs. 10,11 Crocodilian researchers should also consider seriously making use of urine as an indicator of endocrine system abnormalities. Excretion of steroid hormones or metabolites in urine has been well studied in humans.…”

“…Likewise, toxicokinetic and pharmacokinetic studies of non-mammalian species traditionally only use blood samples; yet, most contaminants and pharmaceutical agents are biotransformed to watersoluble metabolites by the liver and excreted in the urine. 10,11 Considering that most crocodilians are listed as endangered or threatened, it is nearly impossible and ethically inappropriate to kill crocodilians for research purposes. 12 Thus, minimally invasive techniques allowing researchers or veterinarians to obtain urine samples from crocodiles, in addition to blood, whether from wild or farmed crocodiles, would contribute significantly to our knowledge and future ability to assess the health status or to diagnose specific diseases in these animals.…”