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203. Directly measured aerobic fitness in male Maasai of Tanzania.

Author

Christensen, Dirk L., Jørgensen, Sine W., Koch, Lars S., Nordsborg, Nikolai B., Sironga, Joseph, Ramaiya, Kaushik L., Larsen, Steen, Brage, Søren, Bygbjerg, Ib C., Maro, Venance P., and Helge, Jørn W.

Subjects
EXERCISE intensity, BLOOD pressure, EXERCISE tests, HEART beat, GAS analysis, FOOD consumption, PHYSICAL activity, GAS exchange in plants
Abstract

Objectives: The agro‐pastoralist Maasai of East Africa are highly physically active, but their aerobic fitness has so far only been estimated using heart rate (HR) response to submaximal exercise and not directly measured. Thus, we aimed to measure aerobic fitness directly using respiratory gas analysis in a group of Maasai, and habitual physical activity energy expenditure (PAEE) as explanatory variable. Methods: In total, 21 (10 rural, 11 semi‐urban) of 30 volunteering Tanzanian Maasai men were eligible to participate. Respiratory gas exchange was measured during a graded exercise test until exhaustion on a stationary bicycle to determine aerobic fitness. Maximal effort criteria were at least two of the following (1) leveling off, (2) respiratory exchange ratio (RER) >1.10, and (3) maximum HR within 10 bpm of age‐estimated maximum HR. Habitual PAEE was estimated using combined accelerometry and HR monitoring. Anthropometry, biochemistry, blood pressure, resting HR, and dietary intake information were collected for background information. Results: Mean age was 43.2 (range 26–60) years, and hemoglobin was higher in the rural versus semi‐urban Maasai (16.9 vs. 15.4 g/dl, p =.02). Mean aerobic fitness (34.4 vs. 33.3 mlO2/min/kg, p =.79), and mean PAEE (58.5 vs. 52.9 kJ/day/kg, p =.64) were similar in rural and semi‐urban Maasai, respectively. Conclusions: Aerobic fitness was low to moderate in male rural and semi‐urban Maasai. This may be explained by relatively low PAEE in comparison to previous objectively measured activity levels in Maasai, which indicates recent lifestyle changes. [ABSTRACT FROM AUTHOR]

Published
2022
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230. Inducible deletion of skeletal muscle AMPKℵ 1 reveals that AMPK is required for nucleotide balance but 2 dispensable for muscle glucose uptake and fat oxidation during exercise

Author

Hingst, Janne, Kjøbsted, Rasmus, Birk, Jesper, Jørgensen, Nicolas, Larsen, Magnus, Kido, Kohei, Larsen, Jeppe, Kjeldsen, Sasha, Fentz, Joachim, Frøsig, Christian, Holm, Stephanie, Fritzen, Andreas, Dohlmann, Tine, Larsen, Steen, Foretz, Marc, Viollet, Benoit, Schjerling, Peter, Overby, Peter, Halling, Jens, Pilegaard, Henriette, Helsten, Ylva, Wojtaszewski, Jørgen, Viollet, Benoit, University of Copenhagen = Københavns Universitet (UCPH), Department of Nutrition, Exercise and Sports [Copenhagen], Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Medical University of Białystok (MUB), Institut Cochin (IC UM3 (UMR 8104 / U1016)), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Copenhagen = Københavns Universitet (KU), University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Medical University of Bialystok [Bialystok, Pologne], and Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
AMPK, [SDV.MHEP.EM] Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism, exercise, glycogen, muscle metabolism, fat oxidation, [SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism, glucose uptake
Abstract

International audience; Objective: Current evidence for AMPK-mediated regulation of skeletal muscle metabolism during exercise is mainly based on transgenic mouse models with chronic (lifelong) disruption of AMPK function. Findings based on such models are potentially biased by secondary effects related to chronic lack of AMPK function. In an attempt to study the direct effect(s) of AMPK on muscle metabolism during exercise, we generated a new mouse model with inducible muscle-specific deletion of AMPKα catalytic subunits in adult mice.Methods: Tamoxifen-inducible and muscle-specific AMPKα1/α2 double KO mice (AMPKα imdKO) were generated using the Cre/loxP system with the Cre driven by the human skeletal muscle actin (HSA) promotor.Results: During treadmill running at the same relative exercise intensity, AMPKα imdKO mice showed greater depletion of muscle ATP, which was associated with accumulation of the deamination product IMP. Muscle-specific deletion of AMPKα in adult mice promptly reduced maximal running speed, muscle glycogen content and was associated with reduced expression of UGP2, a key component of the glycogen synthesis pathway. Muscle mitochondrial respiration, whole body substrate utilization as well as muscle glucose uptake and fatty acid (FA) oxidation during muscle contractile activity remained unaffected by muscle-specific deletion AMPKα subunits in adult mice.Conclusions: Inducible deletion of AMPKα subunits in adult mice reveals that AMPK is required for maintaining muscle ATP levels and nucleotide balance during exercise, but is dispensable for regulating muscle glucose uptake, FA oxidation and substrate utilization during exercise.

Published
2020

235. Inducible deletion of skeletal muscle AMPKα 1 reveals that AMPK is required for nucleotide balance but dispensable for muscle glucose uptake and fat oxidation during exercise

Author

Hingst, Janne Rasmuss, Kjøbsted, Rasmus, Birk, Jesper Bratz, Jørgensen, Nicolas Oldenburg, Larsen, Magnus Romme, Kido, Kohei, Larsen, Jeppe Kjærgaard, Kjeldsen, Sasha Alexandra Sampson, Fentz, Joachim, Frøsig, Christian, Holm, Stephanie, Fritzen, Andreas Mæchel, Dohlmann, Tine Lovsø, Larsen, Steen, Foretz, Marc, Viollet, Benoit, Schjerling, Peter, Overby, Peter, Halling, Jens Frey, Pilegaard, Henriette, Hellsten, Ylva, and Wojtaszewski, Jørgen

Subjects
AMPK, Muscle metabolism, Glucose uptake, Faculty of Science, Fat oxidation, Exercise, Glycogen
Abstract

Objective: Current evidence for AMPK-mediated regulation of skeletal muscle metabolism during exercise is mainly based on transgenic mouse models with chronic (lifelong) disruption of AMPK function. Findings based on such models are potentially biased by secondary effects related to chronic lack of AMPK function. In an attempt to study the direct effect(s) of AMPK on muscle metabolism during exercise, we generated a new mouse model with inducible muscle-specific deletion of AMPKα catalytic subunits in adult mice.Methods: Tamoxifen-inducible and muscle-specific AMPKα1/α2 double KO mice (AMPKα imdKO) were generated using the Cre/loxP system with the Cre driven by the human skeletal muscle actin (HSA) promotor.Results: During treadmill running at the same relative exercise intensity, AMPKα imdKO mice showed greater depletion of muscle ATP, which was associated with accumulation of the deamination product IMP. Muscle-specific deletion of AMPKα in adult mice promptly reduced maximal running speed, muscle glycogen content and was associated with reduced expression of UGP2, a key component of the glycogen synthesis pathway. Muscle mitochondrial respiration, whole body substrate utilization as well as muscle glucose uptake and fatty acid (FA) oxidation during muscle contractile activity remained unaffected by muscle-specific deletion AMPKα subunits in adult mice.Conclusions: Inducible deletion of AMPKα subunits in adult mice reveals that AMPK is required for maintaining muscle ATP levels and nucleotide balance during exercise, but is dispensable for regulating muscle glucose uptake, FA oxidation and substrate utilization during exercise.

Published
2020

236. At slå sig på det sociale

Author

Larsen, Steen Nepper

Subjects
Videregående uddannelse, Pædagogisk filosofi, Studerende, Undervisning
Published
2020

240. Engang søgte du på Google, nu søger Google i dig

Author

Larsen, Steen Nepper

Abstract

Anmeldelse af Shoshana Zuboff: Overvågningskapitalismens tidsalder. Kampen for en menneskelig fremtid ved magtens nye frontlinje; Informations Forlag 2019, 700 sider, 399 kr

Published
2020

241. Increased postprandial responses of GLP-1 and GIP in patients with chronic pancreatitis and steatorrhea following pancreatic enzyme substitution

Author

Knop, Filip K., Vilsboll, Tina, Larsen, Steen, Hojberg, Patricia V., Volund, Aage, Madsbad, Sten, Holst, Jens J., and Krarup, Thure

Subjects
Glucagon -- Research, Pancreatitis -- Research, Celiac disease -- Research, Celiac disease -- Physiological aspects, Biological sciences
Abstract

We aimed to investigate how assimilation of nutrients affects the postprandial responses of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) and to evaluate the effect of pancreatic enzyme substitution (PES) on insulin secretion in patients with chronic pancreatitis (CP) and pancreatic exocrine insufficiency (PEI). Eight male patients with CP and PEI were studied. Blood was sampled frequently on two separate days after ingestion of a liquid meal with and without PES, respectively. Eight healthy male subjects served as a control group. [beta]-Cell responsiveness was estimated as changes in insulin secretion rates in response to changes in postprandial plasma glucose (PG). There was no difference in the PG incremental area under curve (AUC) for patients with and without PES [406 [+ or -] 100 vs. 425 [+ or -] 80 mM * 4 h (mean [+ or -] SE), P = 0.8]. The response of total GLP-1 was higher after PES (AUC: 7.8 [+ or -] 1.2 vs. 5.3 [+ or -] 0.6 nM * 4 h, P = 0.01), as was the response of total GIP (AUC: 32.7 [+ or -] 7.5 vs. 21.1 [+ or -] 8.3 nM * 4 h, P = 0.01). Concurrently, both plasma insulin, plasma C-peptide, and total insulin secretion increased after PES (AUC: 17.7 [+ or -] 4.2 vs. 13.6 [+ or -] 2.9 nM * 4 h, P = 0.02; 237 [+ or -] 31.4 vs. 200 [+ or -] 27.4 nM * 4 h, P = 0.005; and 595 [+ or -] 82 vs. 497 [+ or -] 80 pmol * [kg.sup.-1] * 4 h, P = 0.01, respectively). [beta]-Cell responsiveness to glucose was not significantly different on the two study days for patients with CP. These results suggest that the secretion of GLP-1 and GIP is under influence of the digestion and absorption of nutrients in the small intestine and that PES increases insulin secretion. pancreatic exocrine insufficiency; glucagon-like peptide-1; glucose-dependent insulinotropic polypeptide

Published
2007

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