Title: Studies of glucuronidation and sulfation in tumor-bearing rats
Abstract: Rats bearing subcutaneous Walker 256 carcinoma or intramuscular Reuber H-35 hepatoma were tested for their ability to metabolize 14C-p-nitrophenol into its sulfate and glucuronide. Amounts of p-nitrophenyl glucuronide (PNPGA) and p-nitrophenyl sulfate (PNPS) excreted by the Walker hosts did not differ significantly from those excreted by the controls. Hepatoma hosts, compared with controls, excreted comparable amounts of PNPS but significantly higher amounts of PNPGA. To clarify the basis for the changes in the conjugate levels in urine of the hepatoma hosts, sulfotransferase and glucuronyl transferase activities of the hepatoma and of host and control livers were assayed. The hepatoma possessed significantly higher glucuronyl transferase activity than either type of liver, but had a very low sulfotransferase activity. Microsomal glucuronyl transferase of the hepatoma obeyed Michaelis-Menten kinetics; Km value for p-nitrophenol is 0.22 mM. Liver transferase(s) gave different and irregular kinetics, suggesting qualitative differences between the transferases of the hepatoma and liver.
Publication Year: 1974
Publication Date: 1974-07-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 15
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