Urinary Elimination of Bile Acid Glucuronides under Severe Cholestatic Situations: Contribution of Hepatic and Renal Glucuronidation Reactions

Figure 6

Differential expression of the bile acid-conjugating UGT enzymes in the human liver and kidney. (a) UGTs 1A3, 1A4, 2B4, and 2B7 mRNA levels in total RNA samples from human kidney (1 pool of 5 donors and 2 individual donors) and liver (8 individual donors) were determined through qRT-PCR analyses as described in “Materials and Methods.” Results are expressed as log₁₀ of mRNA copy number per μg of total RNA. Each symbol represents 1 donor, with the exception of the white triangle that corresponds to a pool of the 5 kidney donors. (b) The UGT protein contents in microsomal preparations (5 μg) from human kidney (pool of 4 female and 4 male donors) and liver (pool of 26 male and 24 female donors) were determined after size separation on SDS-PAGE and hybridization with the anti-UGT1A3, anti-UGT2B4/7, anti-UGT2B7, anti-UGT1A, and anti-UGT2B antibodies (1 : 2,000 dilution). The housekeeping protein β-actin was used to ensure the equal protein loading in each lane. Data presented are representative of two experiments. (c) The UGT1A3 protein content in human liver and kidney microsomes was determined using LC-MS/MS analyses as previously described [10]. Data represent the mean ± SD of two different experiments performed in triplicate. N.D: not detected.

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