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- Lind, Lars, et al.
(författare)
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Insulin-mediated vasodilatation, but not glucose uptake or endothelium-mediated vasodilatation, is enhanced in young females compared with males
- 2002
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Ingår i: Clinical Science. - 0143-5221 .- 1470-8736. ; 102:2, s. 241-246
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Tidskriftsartikel (refereegranskat)abstract
- In order to evaluate possible differences between men and women with regard to the ability of insulin to induce vasodilatation, promote glucose uptake and enhance endothelium-dependent vasodilatation, 12 young (22-28 years), non-obese women and 15 corresponding males were subjected to 2 h of euglycaemic hyperinsulinaemia (insulin infusion rate of 56 m-units x min(-1) x m(-2)). Forearm blood flow was measured by venous occlusion plethysmography. Endothelium-dependent vasodilatation was evaluated by the local intra-arterial infusion of methacholine into the brachial artery (2-4 microg/min). The cardiac index was measured by thoracic bioimpedance. A 2 h period of hyperinsulinaemia increased the plasma insulin concentration to a similar degree in both sexes (females, 84 +/- 8.8 m-units/l; males, 87 +/- 7.5 m-units/l), but induced a more marked increase in forearm blood flow in females than in males (+104 +/- 67% and +52 +/- 30% respectively; P<0.01; 95% confidence interval for difference 11-94%). Furthermore, a significant decrease in total peripheral resistance (-20 +/- 6.9%; P<0.01) and an increase in cardiac index (+23 +/- 13%; P<0.01) were seen in women only (P<0.05 compared with men). Blood pressure and heart rate were not altered in either sex. Whole-body insulin-mediated glucose uptake and forearm glucose uptake did not differ between the sexes, and the ability of insulin to enhance endothelium-dependent vasodilatation (+19%; P<0.01) was similar in men and women. In conclusion, the present study shows that the ability of insulin to cause vasodilatation was greater in non-obese young women compared with men. However, no differences between the sexes were seen with regard to insulin-mediated glucose uptake and the ability of insulin to enhance endothelium-dependent vasodilatation.
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| 2. |
- Lind, Lars, et al.
(författare)
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The impairment in endothelial function induced by non-esterified fattyacids can be reversed by insulin
- 2000
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Ingår i: Clinical Science. - 0143-5221 .- 1470-8736. ; 99:3, s. 169-174
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Tidskriftsartikel (refereegranskat)abstract
- Dyslipidaemia, with elevations of circulating triacylglycerols (triglycerides) and non-esterified (free) fatty acids, and hyperinsulinaemia are often found in the same subjects, the so-called 'insulin resistance syndrome'. The present study aims to investigate how elevated levels of non-esterified fatty acids, hyperinsulinaemia and the combination of these factors affects endothelium-dependent vasodilatation (EDV). Ten volunteers were examined on two occasions. Intralipid (plus heparin) or saline (0.9% NaCl) was infused for 4 h. During the final 2 h, euglycaemic hyperinsulinaemia (80+/-4 m-units/l) was imposed. EDV and endothelium-independent vasodilatation were evaluated in the forearm by local intra-arterial infusion of methacholine or sodium nitroprusside at baseline and after 2 and 4 h. Forearm blood flow was measured by venous occlusion plethysmography. Lipid oxidation was determined by measuring plasma malondialdehyde levels. Infusion of Intralipid plus heparin increased the concentration of non-esterified fatty acids to 2.6+/-1.2 mmol/l and decreased EDV from 27.6+/-8.7 to 21.0+/-5.7 ml x min(-1) x 100 ml(-1) tissue (P < 0.01). This effect was completely reversed by hyperinsulinaemia (P < 0.01). Hyperinsulinaemia alone increased EDV (to 30.4+/-9.5 ml x min(-1) x 100 ml(-1) tissue; P < 0.01), while endothelium-independent vasodilatation was unaltered by the interventions. Infusion of Intralipid plus heparin increased malondialdehyde levels from 0.67+/-0.22 to 1.2+/-0.37 micromol/l (P < 0.001), while hyperinsulinaemiadid not change the malondialdehyde level. In conclusion, an acute increase in serum levels of non-esterified fatty acids increased lipid oxidation and decreased EDV. The effect on EDV of non-esterified fatty acids could be reversed by hyperinsulinaemia.
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