Epinephrine (EPI) plays a pivotal role in regulating glucose metabolism both in splanchnic and peripheral tissues. Nevertheless, previous studies did not clarify the mechanisms by which EPI affect both glucose disposal processes in peripheral tissues and β-cell secretion. The aim of this study was to investigate, in six normal volunteers, the effects of elevated EPI concentration on peripheral glucose disposal and insulin secretion by using the stable labeled (either [6,6-2H2] or [2-2H1]glucose) intravenous glucose tolerance test (IVGTT) in conjunction with the minimal models of labeled glucose disappearance and C-peptide secretion. Elevated plasma EPI concentration significantly decreased glucose effectiveness (SG*) by 29% (0.0059 ± 0.0013 vs. 0.0083 ± 0.0011 min−1, P < 0.05), and even more, 61%, insulin sensitivity (SI*); (22 ± 6 · 10(4) vs. 54 ± 20 · 10(4) min−1.pmol.l−1; P < 0.01). These findings are not due to an isotopic effect induced by an enhanced glycogen breakdown, because the [2-2H1]glucose tracer, which is not incorporated into glycogen, gave results similar to those of [6,6-2H2]glucose tracer. No differences were observed in first phase cell sensitivity, phi 1, in the EPI study (199 ± 91 vs. 245 ± 144 10(9), NS), but there was a significant increase in the second-phase cell sensitivity to glucose phi 2, (15.2 ± 1.7 vs. 17.7 ± 4.4 10(9).min−1, P < 0.05). In conclusion, EPI selectively impairs peripheral glucose metabolism because of its unique ability to simultaneously and independently decrease glucose effectiveness and insulin sensitivity. Furthermore, EPI enhances phi 2, the ratio between the C-peptide amount secreted during the second phase and the area under the curve of the glucose signal, indicating that the observed increase of C-peptide concentration is due not only to the augmented glucose signal but also to a specific EPI-mediated enhancement of β-cell responsivity to glucose.
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October 01 1996
Epinephrine Exerts Opposite Effects on Peripheral Glucose Disposal and Glucose-Stimulated Insulin Secretion: A Stable Label Intravenous Glucose Tolerance Test Minimal Model Study
Angelo Avogaro;
Angelo Avogaro
Department of Clinical and Experimental Medicine and Azienda Ospedaliera di Padova
Padova, Italy
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Gianna Toffolo;
Gianna Toffolo
Department of Electronics and Informatics, University of Padova
Padova, Italy
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Anna Valerio;
Anna Valerio
Department of Clinical and Experimental Medicine and Azienda Ospedaliera di Padova
Padova, Italy
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Claudio Cobelli
Claudio Cobelli
Department of Electronics and Informatics, University of Padova
Padova, Italy
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Address correspondence and reprint requests to Dr. Angelo Avogaro, Cattedra di Malattie del Metabolismo, Via Giustiniani 2, 35100 Padova, Italy.
Diabetes 1996;45(10):1373–1378
Article history
Received:
June 12 1995
Revision Received:
May 10 1996
Accepted:
May 10 1996
PubMed:
8826974
Citation
Angelo Avogaro, Gianna Toffolo, Anna Valerio, Claudio Cobelli; Epinephrine Exerts Opposite Effects on Peripheral Glucose Disposal and Glucose-Stimulated Insulin Secretion: A Stable Label Intravenous Glucose Tolerance Test Minimal Model Study. Diabetes 1 October 1996; 45 (10): 1373–1378. https://doi.org/10.2337/diab.45.10.1373
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