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Lundqvist, Martin H.
Publications (3 of 3) Show all publications
Pereira, M. J., Thombare, K., Sarsenbayeva, A., Kamble, P. G., Almby, K., Lundqvist, M. & Eriksson, J. W. (2020). Direct effects of glucagon on glucose uptake and lipolysis in human adipocytes. Molecular and Cellular Endocrinology, 503, Article ID 110696.
Open this publication in new window or tab >>Direct effects of glucagon on glucose uptake and lipolysis in human adipocytes
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2020 (English)In: Molecular and Cellular Endocrinology, ISSN 0303-7207, E-ISSN 1872-8057, Vol. 503, article id 110696Article in journal (Refereed) Published
Abstract [en]

We aim to investigate the expression of the glucagon receptor (GCGR) in human adipose tissue, and the impact of glucagon in glucose uptake and lipolysis in human adipocytes. GCGR gene expression in human subcutaneous and visceral adipose tissue was demonstrated, albeit at low levels and with an inter-individual variation. Furthermore, GCGR expression was not significantly different between subjects with T2D and matched controls, and we found no significant association with BMI. Glucagon only at a supra-physiological concentration (10-100 nM) significantly increased basal and insulin-stimulated glucose uptake by up to 1.5-fold. Also, glucagon (0.01 and 1 nM) dose-dependently increased basal and isoproterenol-stimulated lipolysis up to 3.7- and 1.7-fold, respectively, compared to control. In addition, glucagon did not change insulin sensitivity to stimulate glucose uptake or inhibit lipolysis. In conclusion, we show that the GCGR gene is expressed at low levels in human adipose tissue, and glucagon at high concentrations can increase both glucose uptake and lipolysis in human adipocytes. Taken together, our data suggest that glucagon at physiological levels has minor direct effects on the regulation of adipocyte metabolism, but does not antagonize the insulin effect to stimulate glucose uptake and inhibit lipolysis in human adipocytes.

Place, publisher, year, edition, pages
ELSEVIER IRELAND LTD, 2020
Keywords
Glucagon, Adipose tissue, Metabolism, Glucose uptake, Lipolysis, Glucagon receptor
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:uu:diva-406177 (URN)10.1016/j.mce.2019.110696 (DOI)000508636400010 ()31891768 (PubMedID)
Available from: 2020-03-06 Created: 2020-03-06 Last updated: 2020-03-06Bibliographically approved
Almby, K. E., Abrahamsson, N., Lundqvist, M. H., Hammar, U., Thombare, K., Panagiotou, A., . . . Eriksson, J. (2019). Effects of GLP-1 on counter-regulatory responses during hypoglycemia after GBP surgery. European Journal of Endocrinology, 181(2), 161-171
Open this publication in new window or tab >>Effects of GLP-1 on counter-regulatory responses during hypoglycemia after GBP surgery
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2019 (English)In: European Journal of Endocrinology, ISSN 0804-4643, E-ISSN 1479-683X, Vol. 181, no 2, p. 161-171Article in journal (Refereed) Published
Abstract [en]

Objectives: The aim of the study was to explore the role of GLP-1 receptor activation on the counter-regulation and symptoms of hypoglycemia in subjects who have undergone gastric bypass surgery (GBP).

Design: Experimental hyperinsulinemic-hypoglycemic clamp study.

Methods: Twelve post-GBP subjects participated in a randomized cross-over study with two hyperinsulinemic, hypoglycemic clamps (glucose nadir 2.7 mmol/L) performed on separate days with concomitant infusions of the GLP-1 analog exenatide or with saline, respectively. Continuous measurements of metabolites and counter-regulatory hormones as well as assessments of heart rate variability and symptoms of hypoglycemia were performed throughout the clamps.

Results: No effect of GLP-1 receptor activation on counter-regulatory hormones (glucagon, catecholamines, cortisol, GH) or glucose infusion rate was seen, but we found indications of a downregulation of the sympathetic relative to the parasympathetic nerve activity, as reflected in heart rate variability. No significant differences in symptom of hypoglycemia were observed.

Conclusions/interpretation: Short-term exposure to a GLP-1 receptor agonist does not seem to impact the counter-regulatory hormonal and metabolic responses in post-GBP subjects during hypoglycemic conditions, suggesting that the improvement in symptomatic hypoglycemia post-GBP seen following treatment with GLP-1 receptor agonists may be mediated by mechanism not directly involved in counter-regulation.

Place, publisher, year, edition, pages
BIOSCIENTIFICA LTD, 2019
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:uu:diva-390513 (URN)10.1530/EJE-19-0171 (DOI)000472835100013 ()31176298 (PubMedID)
Funder
Swedish Diabetes AssociationErnfors FoundationEXODIAB - Excellence of Diabetes Research in Sweden
Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-12Bibliographically approved
Sarsenbayeva, A., Marques-Santos, C. M., Thombare, K., Di Nunzio, G., Almby, K. E., Lundqvist, M. H., . . . Pereira, M. J. (2019). Effects of second-generation antipsychotics on human subcutaneous adipose tissue metabolism. Psychoneuroendocrinology, 110, Article ID 104445.
Open this publication in new window or tab >>Effects of second-generation antipsychotics on human subcutaneous adipose tissue metabolism
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2019 (English)In: Psychoneuroendocrinology, ISSN 0306-4530, E-ISSN 1873-3360, Vol. 110, article id 104445Article in journal (Refereed) Published
Abstract [en]

Objective: Metabolic syndrome is prevalent in up to 50% of schizophrenia patients, which reduces their quality of life and their compliance with the treatment. It is unclear whether metabolic adverse effects of these agents are due to their direct effect on insulin-sensitive tissues or are secondary to increased adiposity. The study aimed to investigate the direct effects of the second-generation antipsychotics olanzapine and aripiprazole on human subcutaneous adipose tissue and isolated adipocyte metabolism.

Methods: Abdominal subcutaneous adipose tissue needle biopsies were taken from 72 healthy subjects (49 F/23 M; age: 19-78 yr; BMI: 20.0-35.6 kg/m(2)). Isolated adipocytes or adipose tissue were respectively pre-incubated short- (30 min) and long-term (24 h, 72 h) with or without olanzapine (0.004 mu M - 20 mu M) and aripiprazole (0.002 mu M - 100 mu M). Pre-incubated adipose tissue was then snap-frozen for mRNA expression analysis of adipokines genes and genes involved in inflammation, adipogenesis, and mitochondrial function. Isolated adipocytes were used to measure basal and insulin-stimulated glucose uptake and lipolysis.

Results: Acute treatment with a therapeutic concentration of olanzapine decreases basal lipolysis in isolated adipocytes; this effect was not observed after long-term incubation with the drug. Supra-therapeutic concentration of aripiprazole reduced basal and insulin-stimulated glucose uptake after short- and long-term preincubation. Both drugs at supra-therapeutic concentrations downregulated the expression of the pro-inflammatory cytokines IL6 and IL1B genes after 72 h incubation. Similarly, supra-therapeutic concentrations of both drugs and therapeutic concentration of olanzapine, reduced the expression of PPARGC1A, PDK4, and CPT1B genes involved in the regulation of mitochondria] functions. Neither of the antipsychotics affected the expression of the main adipokines LEP and ADIPOQ, genes involved in the regulation of lipid metabolism, LPL and FASN, nor the master adipogenesis regulator, PPARG.

Conclusion: Therapheutic concentrations of olanzapine and aripiprazole have a moderate direct effect on adipocyte lipid and glucose metabolism, respectively. At supra-therapeutic concentrations, both of the antipsychotics seem to act as anti-inflammatory agents and mildly suppressed genes involved in the regulation of mitochondrial functions, which could potentially contribute to metabolic adverse effects. Alternatively, second-generation antipsychotics could induce metabolic side effects via acting on other insulin-sensitive tissues and central nervous system.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
Second-generation antipsychotics, Adipose tissue, Glucose metabolism, Lipid metabolism, Mitochondrial dysfunction, Inflammation
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:uu:diva-400415 (URN)10.1016/j.psyneuen.2019.104445 (DOI)000500388600024 ()31563732 (PubMedID)
Funder
Swedish Society for Medical Research (SSMF)Swedish Diabetes AssociationEXODIAB - Excellence of Diabetes Research in Sweden
Available from: 2020-01-02 Created: 2020-01-02 Last updated: 2020-01-02Bibliographically approved
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