Tests of the liver specificity of drug glucuronidation

Hellerstein and Landau and their coworkers have developed the glucuronide conjugate approach to aid in the analysis of pathways of liver carbohydrate metabolism. This approach requires that the liver is essentially the sole site of glucuronidation of the given drug. Since UDPglucuronyl transferases are present also in other tissues, most notably the kidney and intestines, we need to test the liver specificity of this process. We develop isotopic approaches to do this, based upon a comparison of the specific activity of the conjugate with that of plasma glucose and liver glucose-6P.