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Dimethylaminopurine inhibits metabolic effects of insulin in primary adipocytes.

Author:
  • Olga Göransson
  • Mikael Rydén
  • Rebecka Nilsson
  • Peter Arner
  • Eva Degerman
Publishing year: 2004
Language: English
Pages: 303-312
Publication/Series: Journal of Nutritional Biochemistry
Volume: 15
Issue: 5
Document type: Journal article
Publisher: Elsevier

Abstract english

Dimethylaminopurine (DMAP) has previously been used as an inhibitor of phosphorylation in studies of meiotic events, and more recently to investigate TNFα signaling, because of its potential to inhibit activation of c-jun N-terminal kinase (JNK). Here we have addressed the effects of DMAP on metabolic insulin responses in adipocytes and on intracellular insulin signaling molecules.



At 100 μmol/L, DMAP completely inhibited the ability of insulin to counteract lipolysis in isolated adipocytes. Insulin-induced lipogenesis and glucose uptake was inhibited to a lesser degree in a concentration-dependent manner starting at 10 μmol/L DMAP. Insulin-induced tyrosine phosphorylation of the insulin receptor was not affected by DMAP. Insulin-induced activation of protein kinase B, a known mediator of insulin action, was not inhibited by 100 μmol/L, but to a low extent by 1 mmol/L DMAP in intact cells. This inhibition was not sufficient to affect activation of the downstream protein kinase B substrate phosphodiesterase 3B.



The inhibition of activation of JNK as a possible mechanism whereby DMAP affects insulin-induced antilipolysis, lipogenesis, and glucose uptake, was investigated using the JNK inhibitor SP600125. At 100 μmol/L, SP600125 completely reversed the antilipolytic effect of insulin, as well as partially inhibited insulin-induced lipogenesis and glucose-uptake, indicating that JNK may be involved in mediating these actions of insulin. Inhibition of JNK by DMAP may therefore partly explain the negative impact of DMAP on insulin action in adipocytes.

Keywords

  • Nutrition and Dietetics
  • Antilipolysis
  • DMAP
  • PKB
  • JNK
  • Insulin
  • Adipocyte

Other

Published
  • Insulin Signal Transduction
  • Protein Phosphorylation
  • ISSN: 1873-4847
Eva Degerman
E-mail: eva.degerman [at] med.lu.se

Professor

Insulin Signal Transduction

+46 46 222 85 83

+46 70 885 83 62

BMC C1121b

66

Lund University Diabetes Centre, CRC, SUS Malmö, Entrance 72, House 91:12. SE-205 02 Malmö. Telephone: +46 40 39 10 00