Interactions of urea transport and synthesis in hepatocytes of the gulf toadfish, Opsanus beta

Patrick J. Walsh, Chris M. Wood

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Although urea transport is receiving increased attention in mammalian systems, little is known about urea transport in fish tissues. Recently, we identified a phloretin-sensitive urea efflux pathway in hepatocytes of gulf toadfish (Opsanus beta), a ureogenic teleost. The present study sought to further examine this transport system and its potential interrelation with metabolic urea production. The transport inhibitors phloretin and 1-(3,4-dichlorophenyl)-2-thiourea (DCPTU) both had substantial inhibitory effects on hepatocyte urea production rates. These effects could be at least partially explained by inhibition of glutamate dehydrogenase (by phloretin) and argininosuccinate synthetase (by DCPTU) activities in vitro. Whereas phloretin substantially inhibited the efflux transport of urea, DCPTU did not. The metabolic effects of phloretin could be nearly eliminated by preparing hepatocytes in the absence of hyaluronidase, enabling its transport effects to be studied in isolation. In so doing we found that transporter inhibition did not lead to a substantial short-term buildup of intracellular urea concentration in hepatocytes. These results are discussed in the context of in vitro vs in vivo rates and pathways of urea transport or excretion.

Original languageEnglish
Pages (from-to)411-416
Number of pages6
JournalComparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Volume113
Issue number2
DOIs
StatePublished - Jan 1 1996

Fingerprint

Batrachoidiformes
Phloretin
Urea
Hepatocytes
Thiourea
Argininosuccinate Synthase
Glutamate Dehydrogenase
Hyaluronoglucosaminidase
Fish
Fishes
Tissue

Keywords

  • 1-(3,4-dichlorophenyl) -2-thiourea
  • gulf toadfish
  • hepatocytes
  • hyaluronidase
  • Opsanus beta
  • ornithine-urea cycle
  • phloretin-sensitive urea transport
  • ureogenesis

ASJC Scopus subject areas

  • Biochemistry
  • Physiology

Cite this

Interactions of urea transport and synthesis in hepatocytes of the gulf toadfish, Opsanus beta. / Walsh, Patrick J.; Wood, Chris M.

In: Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology, Vol. 113, No. 2, 01.01.1996, p. 411-416.

Research output: Contribution to journalArticle

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