Horm Metab Res 2014; 46(09): 615-620
DOI: 10.1055/s-0034-1370967
Endocrine Research
© Georg Thieme Verlag KG Stuttgart · New York

Higher Insulin Sensitivity and Impaired Insulin Secretion in Cachetic Solid Ehrlich Tumour-Bearing Mice

N. M. Violato
1   Institute of Bioscience, São Paulo State University, Botucatu, SP, Brazil
,
A. Rafacho
2   Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, SC, Brazil
,
A. C. Boschero
3   Department of Structural and Functional Biology, Institute of Biology, State University of Campinas, Campinas, SP, Brazil
,
J. R. Bosqueiro
4   Department of Physical Education, Faculty of Sciences, São Paulo State University, Bauru, SP, Brazil
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Publikationsverlauf

received 19. September 2013

accepted 12. Februar 2014

Publikationsdatum:
18. März 2014 (online)

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Abstract

Insulin secretion is mainly regulated by blood glucose concentration. On the other hand, changes in peripheral insulin sensitivity induce compensatory adaptations in pancreatic β-cells to maintain normoglycaemia. Tumour presence causes dramatic alterations in glucose homeostasis and insulin secretion because of the high glucose consumption by the tumour cells. Here, we investigated insulin secretion in solid Ehrlich tumour-bearing mice in association with cachexia. For that, male adult Swiss mice were subcutaneously inoculated with solid Ehrlich tumour cells and sacrificed at 14 days after tumour implantation (SET), while control mice received saline alone (CTL). Insulin secretion, following different stimuli, glucose tolerance, and insulin sensitivity as well as the expression of key proteins involved in insulin secretion was assessed. The SET group showed decreased glycaemia, insulinaemia, hepatic glycogen and body weight, and increased plasma free fatty acids and triglycerides, characteristics of cancer cachexia. A very interesting finding in this study was the development of higher glucose tolerance and insulin sensitivity in SET group. The dose-response curve of insulin secretion to increasing glucose concentrations (2.8–22.2 mM) showed an EC50 of 10 mM glucose for CTL mice and 13 mM glucose for SET mice. Insulin secretion was significantly reduced in SET islets at 30 mM KCl, 100 μM carbachol, 20 mM arginine, and 20 mM leucine. Moreover, AKT, PKA, PKC, and AchRM3 expressions were reduced by 17% to 24% in SET animals. These results, mainly the augmented insulin sensitivity, show that SET is an interesting model to study alterations in pancreatic function and carbohydrate metabolism in cancer cachexia.