Interleukin 1beta-mediated inhibition of arginase in RINm5F cells

Cytokine. 1997 Aug;9(8):570-6. doi: 10.1006/cyto.1996.0203.

Abstract

Induction of nitric oxide synthase and generation of nitric oxide in pancreatic islet beta-cells may mediate cytokine-induced dysfunction leading to insulin-dependent diabetes mellitus. Nitric oxide generation can be regulated by availability of arginine substrate which, in turn, may be affected by substrate utilization in competing pathways such as the arginase-catalysed formation of ornithine and urea. In this study we have investigated the activity of arginase in the rat insulinoma-derived cell line RINm5F and the effect on this of interleukin 1beta, the nitric oxide synthase reaction intermediate NG-hydroxy-l-arginine and the nitric oxide-generating compounds 3-morpholinosydnonimine and S-nitrosoglutathione. Cytosols from RINm5F cells treated with or without interleukin 1beta (0.1nM, 18h) were incubated (45min, 37 degrees C) with [U-14C]arginine. Radiolabelled products ([14C]citrulline from nitric oxide synthase, [14C]ornithine and [14C]urea from arginase) were separated by high-performance liquid chromatography or ion-exchange chromatography. Interleukin 1beta increased citrulline production (from 0.01+/-0.002 to 0.58+/-0.03 pmol/microg cell protein), indicating induction of nitric oxide synthase, and significantly decreased production of both ornithine (from 4.60+/-0.20 to 3.40+/-0.20 pmol/microg) and urea (0.93+/-0.05 to 0.69+/-0.04 pmol/microg) (P<0.001), indicating decreased activity of arginase. Arginase was significantly inhibited by NG-hydroxy-l-arginine (IC50=50 microM), S-nitrosoglutathione (500 microM: 69+/-7% of control) and 3-morpholinosydnonimine (1 mM: 57+/-7% of control) (P<0.05). We conclude that during cytokine-directed beta-cell assault nitric oxide synthase-catalysed production of NG-hydroxy-l-arginine and nitric oxide may inhibit arginase thereby increasing the availability of arginine for nitric oxide production.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arginase / antagonists & inhibitors*
  • Arginine / isolation & purification
  • Citrulline / isolation & purification
  • Enzyme Inhibitors / pharmacology
  • Glutathione / analogs & derivatives
  • Glutathione / pharmacology
  • Insulinoma
  • Interleukin-1 / pharmacology*
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / enzymology
  • Molsidomine / analogs & derivatives
  • Molsidomine / pharmacology
  • Nitric Oxide Synthase / metabolism
  • Nitroso Compounds / pharmacology
  • Ornithine / isolation & purification
  • Rats
  • S-Nitrosoglutathione
  • Tumor Cells, Cultured

Substances

  • Enzyme Inhibitors
  • Interleukin-1
  • Nitroso Compounds
  • Citrulline
  • S-Nitrosoglutathione
  • linsidomine
  • Arginine
  • Molsidomine
  • Ornithine
  • Nitric Oxide Synthase
  • Arginase
  • Glutathione