| 1. |
- Bang, Peter, et al.
(författare)
-
Free dissociable IGF-I : Association with changes in IGFBP-3 proteolysis and insulin sensitivity after surgery
- 2016
-
Ingår i: Clinical Nutrition. - : Churchill Livingstone. - 0261-5614 .- 1532-1983. ; 35:2, s. 408-413
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Patients receiving a carbohydrate drink (CHO) before major abdominal surgery display improved insulin sensitivity postoperatively and increased proteolysis of IGFBP-3 (IGFBP-3-PA) compared to patients undergoing similar surgery after overnight fasting. Aims: We hypothesized that serum IGFBP-3-PA increases bioavailability of circulating IGF-I and preserves insulin sensitivity in patients given CHO. Design: Matched control study. Methods: At Karolinska University Hospital, patients given CHO before major elective abdominal surgery (CHO,n = 8) were compared to patients undergoing similar surgical procedures after overnight fasting (FAST,n = 10). Results from two different techniques for determination of free-dissociable IGF-I (fdIGF-I) were compared with changes in IGFBP-3-PA and insulin sensitivity. Results: Postoperatively, CHO displayed 18% improvement in insulin sensitivity (hyperinsulinemic clamp) and increased IGFBP-3-PA vs. FAST. As determined by IRMA, fdIGF-I increased by 48 +/- 25% in CHO while fdIGF-I decreased by 13 +/- 18% in FAST (p < 0.01 vs. CHO, when corrected for duration of surgery). However, fdIGF-I determined by ultra-filtration decreased similarly in both groups (-22 +/- 8% vs. -25 +/- 8%, p = 0.8) and IGFBP-1 increased similarly in both groups. Patients with less insulin resistance after surgery demonstrated larger increases in fdIGF-I by IRMA (r = 0.58, p < 0.05). Fifty-three % of the variability of the changes in fdIGF-I by IRMA could be explained by changes in IGFBP-3-PA and total IGF-I levels (p < 0.05), while IGFBP-1 did not contribute significantly. Conclusion: During conditions when serum IGF-I bioavailability is regulated by IGFBP-3 proteolysis, measurements of fdIGF-I by IRMA is of physiological relevance as it correlates with the associated changes in insulin sensitivity.
|
|
| 2. |
- Nygren, Jonas, et al.
(författare)
-
Glucose flux is normalized by compensatory hyperinsulinaemia in growth hormone-induced insulin resistance in healthy subjects, while skeletal muscle protein synthesis remains unchanged.
- 2002
-
Ingår i: Clinical Science. - London, United Kingdom : Portland Press. - 0143-5221 .- 1470-8736. ; 102:4, s. 457-64
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this present investigation was to study the relationship between the reduction in insulin sensitivity accompanying 5 days of treatment with growth hormone (GH; 0.05 mg.24 h(-1).kg(-1)) and intracellular substrate oxidation rates in six healthy subjects, while maintaining glucose flux by a constant glucose infusion and adjusting insulin infusion rates to achieve normoglycaemia (feedback clamp). Protein synthesis rates in skeletal muscle (flooding dose of L-[(2)H(5)]phenylalanine) were determined under these conditions. We also compared changes in insulin sensitivity after GH treatment with simultaneous changes in energy requirements, protein synthesis rates, nitrogen balance, 3-methylhistidine excretion in urine, body composition and the hormonal milieu. After GH treatment, 70% more insulin was required to maintain normoglycaemia (P<0.01). The ratio between glucose infusion rate and serum insulin levels decreased by 34% at the two levels of glucose infusion tested (P<0.05). Basal levels of C-peptide, insulin-like growth factor (IGF)-I and IGF-binding protein-3 increased almost 2-fold, while levels of glucose, insulin, glucagon, GH and IGF-binding protein-1 remained unchanged. Non-esterified fatty acid levels decreased (P<0.05). In addition, 24 h urinary nitrogen excretion decreased by 26% (P<0.01) after GH treatment, while skeletal muscle protein synthesis and 3-methylhistidine excretion in urine remained unchanged. Energy expenditure increased by 5% (P<0.05) after treatment, whereas fat and carbohydrate oxidation were unaltered. In conclusion, when glucose flux was normalized by compensatory hyperinsulinaemia under conditions of GH-induced insulin resistance, intracellular rates of oxidation of glucose and fat remained unchanged. The nitrogen retention accompanying GH treatment seems to be due largely to improved nitrogen balance in non-muscle tissue.
|
|
| 3. |
- Rooyackers, Olav, et al.
(författare)
-
Insulin stimulated glucose disposal in peripheral tissues studied with microdialysis and stable isotope tracers
- 2004
-
Ingår i: Clinical Nutrition. - Edinburgh, United Kingdom : Churchill Livingstone. - 0261-5614 .- 1532-1983. ; 23:4, s. 743-52
-
Tidskriftsartikel (refereegranskat)abstract
- Background & aims: Methods to study glucose kinetics in vivo in specific tissues or tissue beds in humans are often not feasible due to invasiveness or costs of equipment needed. Here we investigate whether the loss (fractional extraction) of 2H7-glucose infused via a microdialysis catheter can be used to study glucose disposal in skeletal muscle and subcutaneous adipose tissue.Methods and results: A perfusion period of 2 h was needed to ensure an isotopic steady state in the microdialysis catheters in skeletal muscle and adipose tissue. In six healthy volunteers the fractional extraction increased during a hyperinsulinemic euglycemic clamp in both skeletal muscle and adipose tissue. Following 48 h of starvation in the same subjects, insulin was not able to increase the fractional extraction of 2H7-glucose from the microdialysis in comparison with a baseline measurement.Conclusions: In response to insulin infusion, the fractional extraction of 2H7-glucose from a microdialysis catheter increases in skeletal muscle and subcutaneous adipose tissue and this increase is blunted during insulin resistance induced by starvation. These results validate that the fractional extraction of a glucose tracers infused via microdialysis can be used as an index of glucose disposal in peripheral tissues or tissue beds.
|
|
| 4. |
|
|
| 5. |
- Thorell, Anders, et al.
(författare)
-
Intensive insulin treatment in critically ill trauma patients normalizes glucose by reducing endogenous glucose production
- 2004
-
Ingår i: Journal of Clinical Endocrinology and Metabolism. - Chevy Chase, USA : The Endocrine Society. - 0021-972X .- 1945-7197. ; 89:11, s. 5382-6
-
Tidskriftsartikel (refereegranskat)abstract
- Critical illness is associated with insulin resistance and hyperglycemia. Intensive insulin treatment to normalize blood glucose during feeding has been shown to improve morbidity and mortality in patients in intensive care. The mechanisms behind the glucose-controlling effects of insulin in stress are not well understood. Six previously healthy, severely traumatized patients (injury severity score > 15) were studied early (24-48 h) after trauma. Endogenous glucose production (EGP) and whole-body glucose disposal (WGD) were measured (6,6-(2)H(2)-glucose) at basal, during total parenteral nutrition (TPN), and during TPN plus insulin to normalize blood glucose (TPN+I). Six matched volunteers served as controls. At basal and TPN, concentrations of glucose and insulin were higher in patients (P < 0.05). During TPN+I, insulin concentrations were 30-fold higher in patients. At basal, WGD and EGP were 30% higher in patients (P < 0.05). During TPN, EGP decreased in both groups but less in patients, resulting in 110% higher EGP than controls (P < 0.05). Normoglycemia coincided with reduced EGP, resulting in similar rates in both groups. WGD did not change during TPN or TPN+I and was not different between the groups. In conclusion, in healthy subjects, euglycemia is maintained during TPN at physiological insulin concentrations by a reduction of EGP, whereas WGD is maintained at basal levels. In traumatized patients, hyperglycemia is due to increased EGP. In contrast to controls, normalization of glucose concentration during TPN needs high insulin infusion rates and is accounted for by a reduction in EGP, whereas WGD is not increased.
|
|
| 6. |
|
|
