Evidence for physiological coupling of insulin-mediated glucose metabolism and limb blood flow

2000 ◽  
Vol 279 (6) ◽  
pp. E1264-E1270 ◽  
Author(s):  
Kieren Mather ◽  
Markku Laakso ◽  
Steven Edelman ◽  
Ginger Hook ◽  
Alain Baron
Keyword(s):  
Blood Flow ◽  
Glucose Metabolism ◽  
Whole Body ◽  
Glucose Disposal ◽  
Insulin Stimulation ◽  
Insulin Resistant ◽  
Type 2 Dm ◽  
Glucose Disposal Rate ◽  
Type 2 Diabetic

We hypothesized that the vasodilation observed during insulin stimulation is closely coupled to the rate of glucose metabolism. Lean (L, n = 13), obese nondiabetic (OB, n = 13), and obese type 2 diabetic subjects (Type 2 DM, n = 16) were studied. Leg blood flow (LBF) was examined under conditions of euglycemic hyperinsulinemia (EH) and hyperglycemic hyperinsulinemia (HH), which produced a steady-state whole body glucose disposal rate (GDR) of ∼2,000 μmol · m−2 · min−1. At this GDR, under both conditions, subjects across the range of insulin sensitivity exhibited equivalent LBF (l/min EH: L, 0.42 ± 0.03; OB, 0.43 ± 0.03; Type 2 DM, 0.38 ± 0.07; P= 0.72 by ANOVA. HH: L, 0.44 ± 0.04; OB, 0.39 ± 0.05; Type 2 DM, 0.41 ± 0.04; P = 0.71). The continuous relationship between LBF and GDR did not differ across subject groups [slope × 10−5l/(μmol · m−2 · min−1) by ANOVA. EH: L, 8.6; OB, 9.2; Type 2 DM, 7.9; P = 0.91. HH: L, 4.2; OB, 2.5; Type 2 DM, 4.1; P = 0.77], although this relationship did differ between the EH and HH conditions ( P = 0.001). These findings support a physiological coupling of LBF and insulin-mediated glucose metabolism. The mechanism(s) linking substrate delivery and metabolism appears to be intact in insulin-resistant states.

Effect of IGF-I on FFA and glucose metabolism in control and type 2 diabetic subjects

2002 ◽  
Vol 282 (6) ◽  
pp. E1360-E1368 ◽  
Author(s):  
Thongchai Pratipanawatr ◽  
Wilailak Pratipanawatr ◽  
Clifford Rosen ◽  
Rachele Berria ◽  
Mandeep Bajaj ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Glucose Disposal ◽  
Insulin Resistant ◽  
Control Subjects ◽  
Igf I ◽  
Plasma Ffa ◽  
Type 2 Diabetic

The effects of insulin-like growth factor I (IGF-I) and insulin on free fatty acid (FFA) and glucose metabolism were compared in eight control and eight type 2 diabetic subjects, who received a two-step euglycemic hyperinsulinemic (0.25 and 0.5 mU · kg−1 · min−1) clamp and a two-step euglycemic IGF-I (26 and 52 pmol · kg−1 · min−1) clamp with [3-3H]glucose, [1-14C]palmitate, and indirect calorimetry. The insulin and IGF-I infusion rates were chosen to augment glucose disposal (Rd) to a similar extent in control subjects. In type 2 diabetic subjects, stimulation of Rd (second clamp step) in response to both insulin and IGF-I was reduced by ∼40–50% compared with control subjects. In control subjects, insulin was more effective than IGF-I in suppressing endogenous glucose production (EGP) during both clamp steps. In type 2 diabetic subjects, insulin-mediated suppression of EGP was impaired, whereas EGP suppression by IGF-I was similar to that of controls. In both control and diabetic subjects, IGF-I-mediated suppression of plasma FFA concentration and inhibition of FFA turnover were markedly impaired compared with insulin ( P < 0.01–0.001). During the second IGF-I clamp step, suppression of plasma FFA concentration and FFA turnover was impaired in diabetic vs. control subjects ( P < 0.05–0.01). Conclusions: 1) IGF-I is less effective than insulin in suppressing EGP and FFA turnover; 2) insulin-resistant type 2 diabetic subjects also exhibit IGF-I resistance in skeletal muscle. However, suppression of EGP by IGF-I is not impaired in diabetic individuals, indicating normal hepatic sensitivity to IGF-I.

Muscle glucose transport and phosphorylation in type 2 diabetic, obese nondiabetic, and genetically predisposed individuals

2007 ◽  
Vol 292 (1) ◽  
pp. E92-E100 ◽  
Author(s):  
Merri Pendergrass ◽  
Alessandra Bertoldo ◽  
Riccardo Bonadonna ◽  
Gianluca Nucci ◽  
Lawrence Mandarino ◽  
...  
Keyword(s):  
Glucose Transport ◽  
Brachial Artery ◽  
Glucose Concentration ◽  
Whole Body ◽  
Insulin Resistant ◽  
Normal Glucose ◽  
Glucose Phosphorylation ◽  
Forearm Muscle ◽  
Type 2 Diabetic

Our objectives were to quantitate insulin-stimulated inward glucose transport and glucose phosphorylation in forearm muscle in lean and obese nondiabetic subjects, in lean and obese type 2 diabetic (T2DM) subjects, and in normal glucose-tolerant, insulin-resistant offspring of two T2DM parents. Subjects received a euglycemic insulin (40 mU·m−2·min−1) clamp with brachial artery/deep forearm vein catheterization. After 120 min of hyperinsulinemia, a bolus of d-mannitol/3- O-methyl-d-[14C]glucose/d-[3-3H]glucose (triple-tracer technique) was given into brachial artery and deep vein samples obtained every 12–30 s for 15 min. Insulin-stimulated forearm glucose uptake (FGU) and whole body glucose metabolism (M) were reduced by 40–50% in obese nondiabetic, lean T2DM, and obese T2DM subjects (all P < 0.01); in offspring, the reduction in FGU and M was ∼30% ( P < 0.05). Inward glucose transport and glucose phosphorylation were decreased by ∼40–50% ( P < 0.01) in obese nondiabetic and T2DM groups and closely paralleled the decrease in FGU. The intracellular glucose concentration in the space accessible to glucose was significantly greater in obese nondiabetic, lean T2DM, obese T2DM, and offspring compared with lean controls. We conclude that 1) obese nondiabetic, lean T2DM, and offspring manifest moderate-to-severe muscle insulin resistance (FGU and M) and decreased insulin-stimulated glucose transport and glucose phosphorylation in forearm muscle; these defects in insulin action are not further reduced by the combination of obesity plus T2DM; and 2) the increase in intracelullar glucose concentration under hyperinsulinemic euglycemic conditions in obese and T2DM groups suggests that the defect in glucose phosphorylation exceeds the defect in glucose transport.

scholarly journals Quantitative Measurement of Full-Length and C-Terminal Proteolyzed RBP4 in Serum of Normal and Insulin-Resistant Humans using a Novel Mass Spectrometry Immunoassay

Endocrinology ◽  
2012 ◽  
Vol 153 (3) ◽  
pp. 1519-1527 ◽  
Author(s):  
Qin Yang ◽  
Iratxe Eskurza ◽  
Urban A. Kiernan ◽  
David A. Phillips ◽  
Matthias Blüher ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Metabolic Syndrome ◽  
Full Length ◽  
Clinical Severity ◽  
Glucose Disposal ◽  
Insulin Resistant ◽  
Glucose Disposal Rate

Serum retinol-binding protein 4 (RBP4) levels are increased in insulin-resistant humans and correlate with severity of insulin resistance in metabolic syndrome. Quantitative Western blotting (qWestern) has been the most accurate method for serum RBP4 measurements, but qWestern is technically complex and labor intensive. The lack of a reliable, high-throughput method for RBP4 measurements has resulted in variability in findings in insulin-resistant humans. Many commonly used ELISAs have limited dynamic range. Neither the current ELISAs nor qWestern distinguish among full-length and carboxyl terminus proteolyzed forms of circulating RBP4 that are altered in different medical conditions. Here, we report the development of a novel quantitative mass spectrometry immunoaffinity assay (qMSIA) to measure full-length and proteolyzed forms of RBP4. qMSIA and qWestern of RBP4 were performed in identical serum aliquots from insulin-sensitive/normoglycemic or insulin-resistant humans with impaired glucose tolerance or type 2 diabetes. Total RBP4 qMSIA measurements were highly similar to qWestern and correlated equally well with clinical severity of insulin resistance (assessed by clamp glucose disposal rate, r = −0.74), hemoglobin A1c (r = 0.63), triglyceride/high-density lipoprotein (r = 0.55), waist/hip (r = 0.61), and systolic blood pressure (r = 0.53, all P &lt; 0.001). Proteolyzed forms of RBP4 accounted for up to 50% of total RBP4 in insulin-resistant subjects, and des(Leu)-RBP4 (cleavage of last leucine) correlated highly with insulin resistance (assessed by glucose disposal rate, r = −0.69). In multiple regression analysis, insulin resistance but not glomerular filtration rate was the strongest, independent predictor of serum RBP4 levels. Thus, qMSIA provides a novel tool for accurately measuring serum RBP4 levels as a biomarker for severity of insulin resistance and risk for type 2 diabetes and metabolic syndrome.

Decreased whole body lipolysis as a mechanism of the lipid-lowering effect of pioglitazone in type 2 diabetic patients

2009 ◽  
Vol 297 (1) ◽  
pp. E225-E230 ◽  
Author(s):  
Amalia Gastaldelli ◽  
Arturo Casolaro ◽  
Demetrio Ciociaro ◽  
Silvia Frascerra ◽  
Monica Nannipieri ◽  
...  
Keyword(s):  
Lipid Lowering ◽  
Whole Body ◽  
Diabetic Patients ◽  
Type 2 Diabetic Patients ◽  
Mixed Meal ◽  
Plasma Triglycerides ◽  
Insulin Resistant ◽  
Type 2 Diabetic ◽  
Lipid Lowering Effect

Pioglitazone has been shown to reduce fasting triglyceride levels. The mechanisms of this effect have not been fully elucidated, but decreased lipolysis may contribute to blunt the hypertriglyceridemic response to a meal. To test this hypothesis, we studied 27 type 2 diabetes mellitus (T2DM) patients and 7 sex-, age-, and body mass index-matched nondiabetic controls. Patients were randomized to pioglitazone (45 mg/day) or placebo for 16 wk. Whole body lipolysis was measured [as the [2H5]glycerol rate of appearance (Ra)] in the fasting state and for 6 h following a mixed meal. Compared with controls, T2DM had higher postprandial profiles of plasma triglycerides, free fatty acid (FFA), and β-hydroxybutyrate, and a decreased suppression of glycerol Ra ( P < 0.04) despite higher insulin levels [268 (156) vs. 190 (123) pmol/l, median (interquartile range)]. Following pioglitazone, triglycerides and FFA were reduced ( P = 0.05 and P < 0.04, respectively), and glycerol Ra was more suppressed [−40 (137) vs. +7 (202) μmol/min of placebo, P < 0.05] despite a greater fall in insulin [−85 (176) vs. −20 (58) pmol/l, P = 0.05]. We conclude that, in well-controlled T2DM patients, whole body lipolysis is insulin resistant, and pioglitazone improves the insulin sensitivity of lipolysis.

scholarly journals Glucose-mediated glucose disposal in insulin-resistant normoglycemic relatives of type 2 diabetic patients.

Diabetes ◽  
2000 ◽  
Vol 49 (7) ◽  
pp. 1209-1218 ◽  
Author(s):  
J E Henriksen ◽  
K Levin ◽  
P Thye-Rønn ◽  
F Alford ◽  
O Hother-Nielsen ◽  
...  
Keyword(s):  
Glucose Disposal ◽  
Diabetic Patients ◽  
Type 2 Diabetic Patients ◽  
Insulin Resistant ◽  
Type 2 Diabetic

Blockade of Renin Angiotensin System Ameliorates the Cardiac Arrhythmias and Sympathetic Neural Remodeling in Hearts of Type 2 DM Rat Model

2020 ◽  
Vol 20 (3) ◽  
pp. 464-478 ◽  
Author(s):  
Yomna M. Yehya ◽  
Abdelaziz M. Hussein ◽  
Khaled Ezam ◽  
Elsayed A. Eid ◽  
Eman M. Ibrahim ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Cardiac Arrhythmias ◽  
Sympathetic Nerve ◽  
Renin Angiotensin System ◽  
Diabetic Rats ◽  
Angiotensin System ◽  
Type 2 Dm ◽  
Type 2 Diabetic ◽  
Diabetes Induction

Objectives:: The present study was designed to investigate the effects of renin angiotensin system (RAS) blockade on cardiac arrhythmias and sympathetic nerve remodelling in heart tissues of type 2 diabetic rats. Methods:: Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group: normal rats, b) DM group; after type 2 diabetes induction, rats received 2ml oral saline daily for 4 weeks, c) DM+ ACEi: after type 2 diabetes induction, rats were treated with enalapril (10 mg/kg, orally for 4 weeks) and d) DM+ ARBs: after type 2 diabetes induction, rats were treated with losartan (30 mg/kg, orally for 4 weeks). Results:: In type 2 diabetic rats, the results demonstrated significant prolongation in Q-T interval and elevation of blood sugar, HOMA-IR index, TC, TGs, LDL, serum CK-MB, myocardial damage, myocardial MDA, myocardial norepinephrine and tyrosine hydroxylase (TH) density with significant reduction in serum HDL, serum insulin and myocardial GSH and CAT. On the other hand, blockade of RAS at the level of either ACE by enalapril or angiotensin (Ag) receptors by losartan resulted in significant improvement in ECG parameters (Q-T), cardiac enzymes (CK-MB), cardiac morphology, myocardial oxidative stress (low MDA, high CAT and GSH) and myocardial TH density. Conclusions:: RAS plays a role in the cardiac sympathetic nerve sprouting and cardiac arrhythmias induced by type 2 DM and its blockade might have a cardioprotective effect via attenuation of sympathetic nerve fibres remodelling, myocardial norepinephrine contents and oxidative stress.

Neural control of glucose uptake by skeletal muscle after central administration of NMDA

1995 ◽  
Vol 268 (2) ◽  
pp. R492-R497 ◽  
Author(s):  
C. H. Lang ◽  
M. Ajmal ◽  
A. G. Baillie
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Glucose Uptake ◽  
Neural Control ◽  
Plasma Insulin ◽  
Regional Blood Flow ◽  
Muscle Blood Flow ◽  
Whole Body ◽  
Glucose Disposal ◽  
Central Administration

Intracerebroventricular injection of N-methyl-D-aspartate (NMDA) produces hyperglycemia and increases whole body glucose uptake. The purpose of the present study was to determine in rats which tissues are responsible for the elevated rate of glucose disposal. NMDA was injected intracerebroventricularly, and the glucose metabolic rate (Rg) was determined for individual tissues 20-60 min later using 2-deoxy-D-[U-14C]glucose. NMDA decreased Rg in skin, ileum, lung, and liver (30-35%) compared with time-matched control animals. In contrast, Rg in skeletal muscle and heart was increased 150-160%. This increased Rg was not due to an elevation in plasma insulin concentrations. In subsequent studies, the sciatic nerve in one leg was cut 4 h before injection of NMDA. NMDA increased Rg in the gastrocnemius (149%) and soleus (220%) in the innervated leg. However, Rg was not increased after NMDA in contralateral muscles from the denervated limb. Data from a third series of experiments indicated that the NMDA-induced increase in Rg by innervated muscle and its abolition in the denervated muscle were not due to changes in muscle blood flow. The results of the present study indicate that 1) central administration of NMDA increases whole body glucose uptake by preferentially stimulating glucose uptake by skeletal muscle, and 2) the enhanced glucose uptake by muscle is neurally mediated and independent of changes in either the plasma insulin concentration or regional blood flow.

Sign in / Sign up

Export Citation Format

Share Document