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- Carr, Richard D., et al.
(författare)
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Incretin and islet hormonal responses to fat and protein ingestion in healthy men
- 2008
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Ingår i: American Journal of Physiology: Endocrinology and Metabolism. - : American Physiological Society. - 1522-1555 .- 0193-1849. ; 295:4, s. 779-784
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Tidskriftsartikel (refereegranskat)abstract
- Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) regulate islet function after carbohydrate ingestion. Whether incretin hormones are of importance for islet function after ingestion of noncarbohydrate macronutrients is not known. This study therefore examined integrated incretin and islet hormone responses to ingestion of pure fat (oleic acid; 0.88 g/kg) or protein (milk and egg protein; 2 g/kg) over 5 h in healthy men, aged 20-25 yr (n = 12); plain water ingestion served as control. Both intact (active) and total GLP-1 and GIP levels were determined as was plasma activity of dipeptidyl peptidase-4 (DPP-4). Following water ingestion, glucose, insulin, glucagon, GLP-1, and GIP levels and DPP-4 activity were stable during the 5-h study period. Both fat and protein ingestion increased insulin, glucagon, GIP, and GLP-1 levels without affecting glucose levels or DPP-4 activity. The GLP-1 responses were similar after protein and fat, whereas the early (30 min) GIP response was higher after protein than after fat ingestion (P < 0.001). This was associated with sevenfold higher insulin and glucagon responses compared with fat ingestion (both P < 0.001). After protein, the early GIP, but not GLP-1, responses correlated to insulin (r(2) = 0.86; P = 0.0001) but not glucagon responses. In contrast, after fat ingestion, GLP-1 and GIP did not correlate to islet hormones. We conclude that, whereas protein and fat release both incretin and islet hormones, the early GIP secretion after protein ingestion may be of primary importance to islet hormone secretion.
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- Carr, Richard D, et al.
(författare)
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Secretion and Dipeptidyl Peptidase-4-Mediated Metabolism of Incretin Hormones after a Mixed Meal or Glucose Ingestion in Obese Compared to Lean, Nondiabetic Men.
- 2010
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 95, s. 872-878
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Tidskriftsartikel (refereegranskat)abstract
- Context: Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are cleaved by dipeptidyl peptidase-4 (DPP-4); plasma activity of DPP-4 may be increased in obesity. The impact of this increase on incretin hormone secretion and metabolism is not known. Objective: The aim of the study was to assess incretin hormone secretion and degradation in lean and obese nondiabetic subjects. Design, Settings, and Participants: We studied the ingestion of a mixed meal (560 kcal) or oral glucose (2 g/kg) in healthy lean (n = 12; body mass index, 20-25 kg/m(2)) or obese (n = 13; body mass index, 30-35 kg/m(2)) males at a University Clinical Research Unit. Main Outcome Measures: We measured the area under the curve of plasma intact (i) and total (t) GIP and GLP-1 after meal ingestion and oral glucose. Results: Plasma DPP-4 activity was higher in the obese subjects (38.5 +/- 3.0 vs. 26.7 +/- 1.6 mmol/min . mul; P = 0.002). Although GIP secretion (AUCtGIP) was not reduced in obese subjects after meal ingestion or oral glucose, AUCiGIP was lower in obese subjects (8.5 +/- 0.6 vs. 12.7 +/- 0.9 nmol/liter x 300 min; P < 0.001) after meal ingestion. GLP-1 secretion (AUCtGLP-1) was reduced in obese subjects after both meal ingestion (7.3 +/- 0.9 vs. 10.0 +/- 0.6 nmol/liter x 300 min; P = 0.022) and oral glucose (6.6 +/- 0.8 vs. 9.6 +/- 1.1 nmol/liter x 180 min; P = 0.035). iGLP-1 was reduced in parallel to tGLP-1. Conclusions: 1) Release and degradation of the two incretin hormones show dissociated changes in obesity: GLP-1 but not GIP secretion is lower after meal ingestion and oral glucose, whereas GIP but not GLP-1 metabolism is increased after meal ingestion. 2) Increased plasma DPP-4 activity in obesity is not associated with a generalized augmented incretin hormone metabolism.
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- Lindgren, Ola, et al.
(författare)
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Consequences on islet and incretin hormone responses to dinner by omission of lunch in healthy men
- 2020
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Ingår i: Endocrinology, Diabetes & Metabolism. - : Wiley. - 2398-9238. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Omission of breakfast results in higher glucose and lower insulin and incretin hormone levels after both lunch and dinner. Whether omission of lunch has a similar impact on the following meal is not known. Aim: This study therefore explored whether omission of lunch ingestion affects glucose, islet and incretin hormones after dinner ingestion in healthy subjects. Materials & Methods: Twelve male volunteers (mean age 22 years, BMI 22.5 kg/m2) underwent two test days in random order with standard breakfast and dinner on both days with provision or omission of standard lunch in between. Results: The results showed that throughout the 300 minutes study period, glucose, insulin, glucagon and GIP levels after dinner ingestion did not differ between the two tests. In contrast, C-peptide, and GLP-1 levels were 26%-35% higher at later time points after dinner ingestion when lunch had been omitted (P <.05). Conclusion: We conclude that omission of lunch increases GLP-1 and insulin secretion and possibly also insulin clearance resulting in unchanged glucose and insulin levels after dinner ingestion.
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- Lindgren, Ola, et al.
(författare)
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Differential Islet and Incretin Hormone Responses in Morning vs. Afternoon after Standardized Meal in Healthy Men.
- 2009
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 94:8, s. 2887-2892
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Tidskriftsartikel (refereegranskat)abstract
- Context: The insulin response to meal ingestion is more rapid in the morning than in the afternoon. Whether this is explained by a corresponding variation in the incretin hormones is not known. Objective: Assess islet and incretin hormones after meal ingestion in the morning versus afternoon. Design, Settings and Participants: Ingestion at 8am and at 5pm of a standardized meal (524 kcal) in healthy lean males (n=12) at a University Clinical Research Unit. Main Outcome Measures: 1)Early (30 min) area under the curve (AUC30) of plasma levels of insulin and intact (i) and total (t) glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) after meal ingestion. 2)Estimation of ss-cell function by model analysis of glucose and C-peptide. Results: Peak glucose was lower in the morning than in the afternoon (6.1+/-0.2 vs. 7.4+/-0.3 mmol/l, P=0.001). AUC30insulin (4.9+/-0.6 vs 2.8+/-0.4 nmol/l*30 min; P=0.012), AUC30tGLP-1 (300+/-40 vs. 160+/-30 pmol/l*30 min, P=0.002), AUC30iGIP (0.7+/-0.1 vs. 0.3+/-0.1 nmol/l* 30 min, P=0.002) and AUC30tGIP (1.1+/-0.1 vs. 0.6+/-0.1nmol/l*min, P=0.007) were all higher in the morning. AUC30iGLP-1 (r=0.68, P=0.021) and AUC39iGIP (r=0.78, P=0.001) both correlated to AUC30insulin. Model analysis of ss-cell function showed a higher first hour potentiation factor in the morning (P=0.009). This correlated negatively with the 60 min glucose level (r=-0.63, P<0.001). Conclusions: The early release of GLP-1 and GIP are more pronounced in the morning than in the afternoon. This may contribute to the more rapid early insulin response, more pronounced potentiation of ss-cell function and lower glucose after the morning meal.
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| 8. |
- Lindgren, Ola, et al.
(författare)
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Dissociated incretin hormone response to protein versus fat ingestion in obese subjects.
- 2011
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Ingår i: Diabetes, Obesity and Metabolism. - : Wiley. - 1462-8902. ; 13, s. 863-865
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Tidskriftsartikel (refereegranskat)abstract
- Protein elicits a stronger early (30 min) glucose-dependent insulinotropic polypeptide (GIP) response than fat ingestion in lean individuals, with no difference in glucagon-like peptide-1 (GLP-1). We assessed the incretin hormone response to protein versus fat ingestion in obesity. Equicaloric (8 kcal/kg) fat (olive oil) or protein (whey protein) was ingested by non-diabetic obese male volunteers (BMI >30kg/m(2) ; n=12) and plasma GIP and GLP-1 were determined. We found no difference in the early GIP or GLP-1 responses to fat vs. protein. However, the total 300 min GIP response was greater after fat than after protein ingestion (20.3±3.9 vs. 10.0±2.8 nmol/l x 300 min; P=0.026), whereas the 300 min GLP-1 responses were the same. Thus, in obesity, protein and fat ingestion elicit similar early (30 min) incretin hormone responses, whereas 300 min GIP secretion is more pronounced after fat than protein ingestion.
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| 10. |
- Lindgren, Ola, et al.
(författare)
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Incretin Effect after Oral Amino Acid Ingestion in Humans.
- 2015
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 100:3, s. 1172-1176
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Tidskriftsartikel (refereegranskat)abstract
- Context: The incretin effect is the augmented insulin secretion by oral versus intravenous glucose at matching glucose levels. We previously demonstrated an augmented insulin secretion when fat is given orally rather than intravenously, suggesting an incretin effect also after fat. However, whether there is an incretin effect is also present after amino acid ingestion is not known. Objective: To explore insulin secretion and islet hormones after oral and intravenous amino acid administration at matched total amino acid concentrations in healthy subjects. Design: Amino acid mixture (Vaminolac(R)) was administered orally or intravenously at a rate resulting in matching total amino acid concentrations to twelve male volunteers with age 22.5±1.4 yr and BMI 22.4±1.4 kg/m(2), who had no history of diabetes. Main outcome measures: Area under the 120 min curve (AUC) for insulin, C-peptide, glucagon, intact and total glucagon like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) and insulin secretory rate and insulin clearance. Results: Insulin, C-peptide and glucagon levels increased after both oral and intravenous administration, but insulin secretion was 25% higher after oral than after intravenous amino acid challenges (P=0.006), whereas there was no significant difference in the glucagon response. Intact and total GIP rose after oral but not after intravenous amino acid administration, whereas intact and total GLP-1 levels did not change significantly in either test. Conclusion: Oral amino acid mixture ingestion elicits a stronger insulin secretory response than intravenous amino acid at matching amino acid levels and that this is associated with increased GIP level, suggesting that an incretin effect exists also after oral amino acids, possibly mediated by GIP.
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