Insulin-stimulated glucose transport is dependent on golgi function in isolated working rat heart

Torsten Doenst, Ari M. Cedars, Heinrich Taegtmeyer

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Insulin and epinephrine stimulate glucose uptake through distinct mechanisms. We tested the hypothesis that the golgi apparatus is involved in insulin-stimulated but not epinephrine-stimulated glucose transport and phosphorylation. Methods: We perfused isolated working rat hearts with Krebs-Henseleit buffer containing [2-3H]glucose (5 mmol/l, 0.05 μCi/ml) and Na-oleate (0.4 mmol/l). In the absence or presence of the inhibitor of golgi function, brefeldin A (30 μmol/l), either insulin (1 mU/ml), epinephrine (1 μmol/l), or phenylephrine (100 μmol/l) plus propranolol (10 μmol/l, selective α-adrenergic stimulation) were added to the perfusate. Results: Cardiac power was stable in all groups (between 8.56 ± 0.61 and 10.4 ± 1.11 mW) and increased (34%) with addition of epinephrine, but not with selective α-adrenergic stimulation. Insulin, epinephrine, and selective α-receptor stimulation increased glucose transport and phosphorylation (μmol/min/g dry wt, basal: 1.19 ± 0.13, insulin: 3.89 ± 0.36, epinephrine: 3.46 ± 0.27, α-stimulation: 4.08 ± 0.40). Brefeldin A increased basal glucose transport and phosphorylation and blunted insulin-stimulated but not epinephrine-stimulated glucose transport and phosphorylation. Selective α-stimulated glucose transport and phosphorylation was also blunted by brefeldin A. Conclusions: Both insulin and α-adrenergic stimulation result in glucose transporter translocation from a pool that requires golgi function. Stimulation with epinephrine results in glucose transporter translocation from a pool that does not require golgi function. The stimulating effects of the α-adrenergic pathway on glucose transport and phosphorylation are independent of changes in cardiac performance. (C) 2000 Academic Press.

Original languageEnglish (US)
Pages (from-to)1481-1488
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume32
Issue number8
DOIs
StatePublished - Jan 1 2000
Externally publishedYes

Keywords

  • Brefeldin A
  • Glucose tracer
  • Isolated working rat heart
  • Signal transduction

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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