Changes in hepatic metabolic enzyme activities and biliary excretion of 4-nitrophenol in streptozotocin induced diabetic rats

Attila Almási, Évora Da Ibéria Leite Nogueira Pinto, Noémi Piroska Kovács, Tamás Fischer, Zoltán Markovics, Emil Fischer, Pál Perjési

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Activity of hepatic metabolic enzymes of glucuronidation and sulfation of 4-nitrophenol (PNP) and biliary excretion of its glucuronide (PNP-G) and sulfate (PNP-S) conjugates have been investigated in control and streptozotocin (STZ)-induced diabetic rats. 500 µM PNP solution was luminally perfused in a cannulated jejunal loop for 90 minutes. It was found that biliary excretion of PNP-G was significantly decreased in the diabetic rats. This effect of STZ could be completely reversed by administration of rapid-acting insulin. Activity of hepatic UDP-glucuronyltransferase and β-glucuronidase was also depressed by the STZ pretreatment. Administration of insulin antagonized the inhibitory action of STZ on UDP-glucuronyltransferase, but the reduced activity of β-glucuronidase was not reversed. Biliary excretion of PNP-S was also depressed in the diabetic rats. Whereas, different effects of insulin administration were observed. Namely, the lower biliary excretion rate of PNP-S was not changed after administration of insulin. Activity of the sulfotransferase and the arylsulfatase enzymes was not altered either by STZ pretreatment or by insulin administration. Biliary excretion of PNP was also significantly depressed by STZ and this depression was not changed after insulin administration. The results call attention to hepatobiliary circulation of low molecular weight xenobiotics and their glucuronide and sulfate conjugates.

Original languageEnglish
Article numbere17347
JournalBrazilian Journal of Pharmaceutical Sciences
Issue number1
Publication statusPublished - Jan 1 2018



  • 4-nitrophenol
  • Experimental diabetes
  • Glucuronide conjugate
  • Hepatic excretion
  • Sulfate conjugate

ASJC Scopus subject areas

  • Pharmacology, Toxicology and Pharmaceutics(all)

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