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- Schmidt, P.T., et al.
(författare)
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Circulating ghrelin levels after food intake during different phases of the migrating motor complex in man.
- 2006
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Ingår i: European Journal of Clinical Investigation. - : Wiley. - 0014-2972 .- 1365-2362. ; 36:7, s. 503-509
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Tidskriftsartikel (refereegranskat)abstract
- Background The timing of the migrating motor complexes (MMC) at food intake may influence gastric emptying and release of regulatory hormones. This report studies the relationships between phases I (motor quiescence) and II (intermediate frequency contractions) of MMC and prandial gut hormone response. Materials and methods Seven fasting volunteers ingested a meal during phase I or II of MMC verified by manometry, using paracetamol as a marker for gastric emptying. Blood was sampled before, during and 210 min after food intake for analysis of ghrelin, motilin, insulin and paracetamol. Results The basal level of ghrelin during phase I was 127·5 ± 25·4 pmol L-1 and during phase II was 132·4 ± 24·8 pmol L-1. After food intake during phase I, ghrelin fell to 77·2 ± 10 pmol L-1; in phase II it fell to 82·7 ± 17·8 pmol L-1 within 60 min and returned to baseline levels after 120 min. Baseline levels of motilin were 16 ± 2 pmol L-1 and 18 ± 3 pmol L-1 during phases I and II, respectively. After food, motilin decreased to 8·5 ± 0·7 pmol L-1 and 8·7 ± 1·0 pmol L-1 within 60 min and returned to baseline after 90 min. Insulin levels in phases I and II were 8·1 ± 1·2 mU L-1 and 8·6 ± 0·7 mU L-1, respectively, reaching 138·9 ± 35·6 mU L-1 and 167·4 ± 30·0 mU L-1 at 45 min postprandially. Conclusions The nutritional status of the gastrointestinal tract at food intake had only a limited impact on plasma ghrelin. After food intake, plasma ghrelin drops, similar to motilin, and resumes preprandial levels within 120 min.
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- Kuhl, JE, et al.
(författare)
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Exercise training decreases the concentration of malonyl-CoA and increases the expression and activity of malonyl-CoA decarboxylase in human muscle
- 2006
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Ingår i: American journal of physiology. Endocrinology and metabolism. - : American Physiological Society. - 0193-1849 .- 1522-1555. ; 290:6, s. E1296-E1303
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Tidskriftsartikel (refereegranskat)abstract
- The study was designed to evaluate whether changes in malonyl-CoA and the enzymes that govern its concentration occur in human muscle as a result of physical training. Healthy, middle-aged subjects were studied before and after a 12-wk training program that significantly increased V̇o2 maxby 13% and decreased intra-abdominal fat by 17%. Significant decreases (25–30%) in the concentration of malonyl-CoA were observed after training, 24–36 h after the last bout of exercise. They were accompanied by increases in both the activity (88%) and mRNA (51%) of malonyl-CoA decarboxylase (MCD) in muscle but no changes in the phosphorylation of AMP kinase (AMPK, Thr172) or of acetyl-CoA carboxylase. The abundance of peroxisome proliferator-activated receptor (PPAR)γ coactivator-1α (PGC-1α), a regulator of transcription that has been linked to the mediation of MCD expression by PPARα, was also increased (3-fold). In studies also conducted 24–36 h after the last bout of exercise, no evidence of increased whole body insulin sensitivity or fatty acid oxidation was observed during an euglycemic hyperinsulinemic clamp. In conclusion, the concentration of malonyl-CoA is diminished in muscle after physical training, most likely because of PGC-1α-mediated increases in MCD expression and activity. These changes persist after the increases in AMPK activity and whole body insulin sensitivity and fatty acid oxidation, typically caused by an acute bout of exercise in healthy individuals, have dissipated.
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