Sulphate conjugation species differences

Studies by Klotz et al. (1975,1976a,b) suggest that biliary excretion of diazepam is unimportant in man, but there is some evidence (see above) for species differences (Klotz etal., 1975,1976a van der Kleijn et al., 1971). Urinary excretion of diazepam is mainly in the form of sulphate and glu-curonide conjugates (Mandelli et al., 1978). The main metabolic pathway is demethylation and hydroxylation to metabolites with CNS depressant activity in animals and man. These metabolites are desmethyldiazepam and oxazepam. 

Both groups found, however, that there were certain species differences. For instance, in the cat and the dog, much of the administered adrenochrome was excreted unchanged, whereas in rabbits the main products were adrenolutin and its sulphate conjugate [333]. Rats metabolise adrenochrome to form an unstable yellow pigment [335]. However it seems probable that, in this case, extensive decomposition of the pigment occurred in the solvents used for the chromatographic studies (cf [330]). 

The conjugation of phenol with glucuronic acid is zero in the cat but the facility is present in many other species. Conversely, the conjugation of phenol with sulphate is zero in the pig but the facility is present in many other species. There are many quantitative (and qualitative) differences in the conjugation of arylacetic acids with amino acids. 

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