Original scientific paper
Effects of Tumor Necrosis Factor-a on Insulin Stimulated Amino Acid Transport in Cultured Rat Hepatocytes
Jagoda Roša
Anja Baraba
Josip Roša
Abstract
It has been suggested that tumor necrosis factor alpha (TNF-a) plays a pivotal role in the pathogenesis of insulin resistance. It could act directly or indirectly in liver. The aim of this study was to determine direct short time (4 h) and long time (24 h) action of TNF-a on amino acid transport in cultured rat hepatocytes and possible role of protein kinase C (PKC) in insulin signal pathway and insulin resistance. Hepatocytes were isolated by a modified collagenase perfusion
technique and cultured for 24 h in M 199 medium. In the presence of insulin basal alpha-amino isobutyric acid (AIB) uptake was increased 55%. TNF-a in short time action did not change basal AIB transport, but significantly (25%) increased insulin stimulated uptake. Short time action of TNF-_ was ameliorated by phorbol ester treatment. These results indicated that PKC activation is important in insulin signaling and TNF-a action. TNF-a acting directly did not cause insulin resistance in cultured hepatocytes.
Keywords
amino acid transport; insulin; insulin resistance; protein kinase C; TNF-a
Hrčak ID:
4969
URI
Publication date:
15.6.2005.
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