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Liu H, Yu H, Qiao J, Sun L, Li J, Tan H, Yu Y. Oscillations of C-peptide in the euglycemic clamp and their effect on the pharmacodynamic assessment of insulin preparations. Fundam Clin Pharmacol 2020; 35:771-780. [PMID: 33159695 DOI: 10.1111/fcp.12628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/29/2020] [Accepted: 11/04/2020] [Indexed: 02/05/2023]
Abstract
C-peptide should be continuously suppressed. However, increased postdosing C-peptide is not an uncommon phenomenon in euglycemic clamp studies involving healthy participants. This study aimed to determine the extent to which the postdosing C-peptide increases from the baseline that could affect the accuracy of glucodynamics in euglycemic clamp studies involving healthy subjects. First, 10 healthy males underwent a 10-h euglycemic clamp without exogenous insulin administration to obtain a reference interval (RI) for the ratio of C-peptide after 0 min (CPt ) to baseline C-peptide (CP0 ). Then, the data from a pharmacokinetic and pharmacodynamic study of insulin aspart (IAsp) were analyzed, and 70 eligible clamps were grouped by CPt /CP0 : group A ([CPt /CP0 ]max > upper limit of RI), group B (1<[CPt /CP0 ]max ≤ upper limit of RI), and group C ([CPt /CP0 ]max ≤ 1). The differences in basal and clamped blood glucose, CPt /CP0 , and the pharmacokinetics and pharmacodynamics of IAsp were compared, and the relationship between elevated CPt and the accuracy of pharmacodynamics was analyzed. The RI of CPt /CP0 was 22.7%-152.1%; 1.5 × baseline might be a ceiling for the increase in CPt under stable conditions. The maximum glucose infusion rate (GIR) in group A tended to be higher than that in group B or C (Pfor trend = 0.033). The AUCGIR,0-10h in groups A, B, and C was 1983 ± 650,1682 ± 454, and 1479 ± 440 mg/kg (P = 0.047), respectively, under comparable IAsp exposure. No intergroup difference was detected in clamped glucose, IAsp dose, or body mass index. In conclusion, postdosing C-peptide over 1.5× baseline indicates insufficient inhibition of endogenous insulin secretion, which could compromise the pharmacodynamics of insulin preparations.
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Affiliation(s)
- Hui Liu
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 37 Guoxue Alley, Wuhou District, Chengdu, Sichuan, China
| | - Hongling Yu
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 37 Guoxue Alley, Wuhou District, Chengdu, Sichuan, China
| | - Jingtao Qiao
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 37 Guoxue Alley, Wuhou District, Chengdu, Sichuan, China
| | - Lisi Sun
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 37 Guoxue Alley, Wuhou District, Chengdu, Sichuan, China
| | - Jiaqi Li
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 37 Guoxue Alley, Wuhou District, Chengdu, Sichuan, China
| | - Huiwen Tan
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 37 Guoxue Alley, Wuhou District, Chengdu, Sichuan, China
| | - Yerong Yu
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 37 Guoxue Alley, Wuhou District, Chengdu, Sichuan, China
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Delarue J, Allain-Jeannic G, Guillerm S, Cruciani-Guglielmacci C, Magnan C, Moineau MP, Le Guen V. Interaction of low dose of fish oil and glucocorticoids on insulin sensitivity and lipolysis in healthy humans: A randomized controlled study. Mol Nutr Food Res 2016; 60:886-96. [PMID: 26821227 DOI: 10.1002/mnfr.201500469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 11/08/2015] [Accepted: 12/29/2015] [Indexed: 11/06/2022]
Abstract
SCOPE This study examined the interaction of fish oil (FO) with dexamethasone on glucose and lipid metabolisms in healthy subjects. METHODS AND RESULTS The study included two consecutive parts. Part A (randomized) in 16 subjects studied the effects of dexamethasone (2 days, 2 mg/day) versus placebo (lactose), part B (two parallel subgroups of eight) studied the interaction of FO (3 wk, 840 mg/day of EPA + DHA) with dexamethasone. Insulin sensitivity of lipolysis (d5-glycerol infusion + microdialysis), endogenous glucose production, and muscle glucose uptake were assessed by a three-step hot insulin clamp and substrate oxidation by indirect calorimetry. Dexamethasone induced liver and peripheral insulin resistance, an increase in fat oxidation, and a decrease in suppression of plasma nonesterified fatty acids (NEFAs). FO amplified the effects of dexamethasone by increasing liver and muscle insulin resistance, by reducing suppression of plasma NEFAs and fat oxidation and by increasing adipose tissue (AT) lipolysis. CONCLUSION FO, given at a moderate dose in healthy subjects prior to a very short-term (2 days) low dose of a synthetic glucocorticoid, worsened its deleterious effects on insulin sensitivity. The enhancing effect of FO on fat oxidation and AT lipolysis might be a protective effect toward an increase in fat mass.
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Affiliation(s)
- Jacques Delarue
- Department of Nutritional Sciences & Laboratory of Human Nutrition, University Hospital of Brest, Brest University, Brest, France.,Breton Federation of Food and Human Nutrition (FED4216), University of Brest, Brest, France
| | - Gwenola Allain-Jeannic
- Department of Nutritional Sciences & Laboratory of Human Nutrition, University Hospital of Brest, Brest University, Brest, France
| | - Sophie Guillerm
- Department of Nutritional Sciences & Laboratory of Human Nutrition, University Hospital of Brest, Brest University, Brest, France
| | | | - Christophe Magnan
- BFA, UMR 8251 CNRS, Sorbonne Paris Cité, University Paris Diderot, Paris, France
| | - Marie-Pierre Moineau
- Department of Biochemistry and Pharmacology Toxicology, University Hospital of Brest, Brest University, Brest, France
| | - Valérie Le Guen
- Department of Nutritional Sciences & Laboratory of Human Nutrition, University Hospital of Brest, Brest University, Brest, France
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Christensen MMH, Højlund K, Hother-Nielsen O, Stage TB, Damkier P, Beck-Nielsen H, Brøsen K. Endogenous glucose production increases in response to metformin treatment in the glycogen-depleted state in humans: a randomised trial. Diabetologia 2015; 58:2494-502. [PMID: 26271344 DOI: 10.1007/s00125-015-3733-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 07/28/2015] [Indexed: 01/20/2023]
Abstract
AIMS/HYPOTHESIS Metformin is believed to reduce glucose levels primarily by inhibiting hepatic glucose production. Recent data indicate that metformin antagonises glucagon-dependent glucose output, suggesting that compensatory mechanisms protect against hypoglycaemia. Here, we examined the effect of metformin on glucose metabolism in humans after a glycogen-depleting fast and the role of reduced-function alleles in OCT1 (also known as SLC22A1). METHODS In a randomised, crossover trial, healthy individuals with or without reduced-function alleles in OCT1 were fasted for 42 h twice, either with or without prior treatment with 1 g metformin twice daily. Participants were recruited from the Pharmacogenomics Biobank of the University of Southern Denmark. Treatment allocation was generated by the Good Clinical Practice Unit, Odense University Hospital, Denmark. Variables of whole-body glucose metabolism were assessed using [3-(3)H]glucose, indirect calorimetry and measurement of substrates and counter-regulatory hormones. The primary outcome was endogenous glucose production (EGP). RESULTS Thirty-seven individuals were randomised. Thirty-four completed the study (12 had none, 13 had one and nine had two reduced-function alleles in OCT1). Three were excluded from the analysis because of early dropout. Metformin significantly stimulated glucose disposal rates and non-oxidative glucose metabolism with no effect on glucose oxidation. This increase in glucose utilisation was explained by a concomitant increase in glycolytic flux and accompanied by increased EGP, most likely mediated by increased plasma lactate, glucagon and cortisol levels. There was no effect of reduced-function OCT1 alleles on any of these measures. All individuals completed the glycogen-depleting fast without hypoglycaemia. CONCLUSIONS/INTERPRETATION Metformin stimulates glycolytic glucose utilisation and lactate production in the glycogen-depleted state. This may trigger a rise in glucose counter-regulatory hormones and subsequently an increase in EGP, which protects against hypoglycaemia. TRIAL REGISTRATION ClinicalTrials.gov NCT01400191 FUNDING: Danish Research Council for Health and Disease (0602-02695B) and Odense University Hospital Free Research Fund, 2012.
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Affiliation(s)
- Mette Marie H Christensen
- Department of Public Health, Clinical Pharmacology, University of Southern Denmark, J.B. Winsloews Vej 19, 5000, Odense, Denmark.
| | - Kurt Højlund
- Department of Endocrinology, Odense University Hospital, Odense, Denmark
- Section of Molecular Diabetes & Metabolism, Institute of Molecular Medicine & Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Ole Hother-Nielsen
- Department of Endocrinology, Odense University Hospital, Odense, Denmark
| | - Tore B Stage
- Department of Public Health, Clinical Pharmacology, University of Southern Denmark, J.B. Winsloews Vej 19, 5000, Odense, Denmark
| | - Per Damkier
- Department of Public Health, Clinical Pharmacology, University of Southern Denmark, J.B. Winsloews Vej 19, 5000, Odense, Denmark
- Department of Clinical Chemistry and Pharmacology, Odense University Hospital, Odense, Denmark
| | | | - Kim Brøsen
- Department of Public Health, Clinical Pharmacology, University of Southern Denmark, J.B. Winsloews Vej 19, 5000, Odense, Denmark
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Høst C, Gormsen LC, Hougaard DM, Christiansen JS, Pedersen SB, Gravholt CH. Acute and short-term chronic testosterone fluctuation effects on glucose homeostasis, insulin sensitivity, and adiponectin: a randomized, double-blind, placebo-controlled, crossover study. J Clin Endocrinol Metab 2014; 99:E1088-96. [PMID: 24606070 DOI: 10.1210/jc.2013-2807] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
CONTEXT Low levels of adiponectin and T in men have been shown to predict development of the metabolic syndrome, but the effects of T on glucose metabolism are incompletely understood and may be influenced either directly or indirectly through changes in body composition or in levels of adiponectin. OBJECTIVE The aim of the study was to test whether T exerts its effects on glucose metabolism directly or indirectly. DESIGN, SETTING, AND PARTICIPANTS In a randomized, double-blind, placebo-controlled, crossover study, 12 healthy young males were studied on four separate occasions. They received GnRH agonist treatment 1 month before 3 of 4 trial days to induce castrate levels of T. On trial days, T gel containing either high or low physiological T dose or placebo was applied to the body. On a fourth trial day, participants constituted their own eugonadal controls. INTERVENTION Each study comprised a 5-hour basal period and a 3-hour hyperinsulinemic euglycemic clamp. MAIN OUTCOME MEASURES We measured the effect of acute T on peripheral glucose disposal, total adiponectin and subforms, and other indices of glucose metabolism. RESULTS Short-term hypogonadism was associated with increased high molecular weight adiponectin levels (P < .03) and increased oxidative glucose disposal (P = .03) but not total glucose disposal (P = .07). Acute T treatment was an independent suppressor of high molecular weight adiponectin levels (P = .04) but did not affect total glucose disposal (P = .17). CONCLUSIONS These data show that T can act through putative fast nongenomic pathways to affect adiponectin levels in humans. The early hypogonadal state is characterized by a marked shift in fuel oxidation from lipids toward glucose, which may rely partly on buffering capabilities of adiponectin.
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Affiliation(s)
- Christian Høst
- Department of Endocrinology and Internal Medicine and the Medical Research Laboratories (C.H., L.C.G., J.S.C., S.B.P., C.H.G.), Clinical Institute, Aarhus University Hospital, DK-8000 Aarhus C, Denmark; and Department of Clinical Biochemistry and Immunology (D.M.H.), Statens Serum Institut, 2300 Copenhagen S, Denmark
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Newsom SA, Everett AC, Hinko A, Horowitz JF. A single session of low-intensity exercise is sufficient to enhance insulin sensitivity into the next day in obese adults. Diabetes Care 2013; 36:2516-22. [PMID: 23757424 PMCID: PMC3747878 DOI: 10.2337/dc12-2606] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The purpose of this study was to determine the effect of a relatively modest session of exercise on insulin sensitivity and fatty acid uptake the next day in obese adults. RESEARCH DESIGN AND METHODS Eleven sedentary obese adults (male/female: 3/8; BMI 37 ± 1 kg/m(2); peak oxygen uptake [VO2peak] 20 ± 1 mL/kg/min) completed three experimental trials. On two of these occasions, subjects exercised to expend 350 kcal in the afternoon. These two exercise trials were identical except for the exercise intensity (50% VO2peak [EX50] and 65% VO2peak [EX65]) and the duration of exercise necessary to expend 350 kcal (EX50 = ≈ 70 min; EX65 = ≈ 55 min). Subjects also completed a control trial (CON), without exercise. The next morning, we measured insulin sensitivity (hyperinsulinemic-euglycemic clamp) and whole-body fatty acid uptake (palmitate rate of disappearance from plasma [Rd]). RESULTS Exercise increased insulin sensitivity the next day, but whereas the 35% improvement after EX50 compared with CON was statistically significant (P = 0.01), the 20% improvement after EX65 was not (P = 0.17). Despite nearly identical values between CON and EX65 (P = 0.88), systemic fatty acid uptake was lower after EX50 compared with EX65 (P = 0.02), but not quite significant compared with CON (P = 0.07). Importantly, the change in fatty acid uptake after exercise compared with CON was negatively correlated with the change in insulin sensitivity for all trials (r = -0.60, P = 0.003). CONCLUSIONS A relatively modest single session of exercise in obese adults improved insulin sensitivity the next day, and a reduction in systemic fatty acid uptake in the several hours after exercise may be important for this effect.
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Affiliation(s)
- Sean A Newsom
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, USA
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Sørensen LP, Søndergaard E, Nellemann B, Christiansen JS, Gormsen LC, Nielsen S. Increased VLDL-triglyceride secretion precedes impaired control of endogenous glucose production in obese, normoglycemic men. Diabetes 2011; 60:2257-64. [PMID: 21810597 PMCID: PMC3161323 DOI: 10.2337/db11-0040] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To assess basal and insulin-mediated VLDL-triglyceride (TG) kinetics and the relationship between VLDL-TG secretion and hepatic insulin resistance assessed by endogenous glucose production (EGP) in obese and lean men. RESEARCH DESIGN AND METHODS A total of 12 normoglycemic, obese (waist-to-hip ratio >0.9, BMI >30 kg/m(2)) and 12 lean (BMI 20-25 kg/m(2)) age-matched men were included. Ex vivo-labeled [1-(14)C]VLDL-TGs and [3-(3)H]glucose were infused postabsorptively and during a hyperinsulinemic-euglycemic clamp to determine VLDL-TG kinetics and EGP. Body composition was determined by dual X-ray absorptiometry and computed tomography scanning. Energy expenditure and substrate oxidation rates were measured by indirect calorimetry. RESULTS Basal VLDL-TG secretion rates were increased in obese compared with lean men (1.25 ± 0.34 vs. 0.86 ± 0.34 μmol/kg fat-free mass [FFM]/min; P = 0.011), whereas there was no difference in clearance rates (150 ± 56 vs. 162 ± 77 mL/min; P = NS), resulting in greater VLDL-TG concentrations (0.74 ± 0.40 vs. 0.38 ± 0.20 mmol/L; P = 0.011). The absolute insulin-mediated suppression of VLDL-TG secretion was similar in the groups. However, the percentage reduction (-36 ± 18 vs. -54 ± 10%; P = 0.008) and achieved VLDL-TG secretion rates (0.76 ± 0.20 vs. 0.41 ± 0.19 μmol/kg FFM/min; P < 0.001) were impaired in obese men. Furthermore, clearance rates decreased significantly in obese men, but there was no significant change in lean men (-17 ± 18 vs. 7 ± 20%; P = 0.007), resulting in less percentage reduction of VLDL-TG concentrations in obese men (-22 ± 20 vs. -56 ± 11%; P < 0.001). Insulin-suppressed EGP was similar (0.4 [0.0-0.8] vs. 0.1 [0.0-1.2] mg/kg FFM/min (median [range]); P = NS), and the percentage reduction was equivalent (-80% [57-98] vs. -98% [49-100], P = NS). Insulin-mediated glucose disposal was significantly reduced in obese men. CONCLUSIONS Basal VLDL-TG secretion rates are increased in normoglycemic but insulin-resistant, obese men, resulting in hypertriglyceridemia. Insulin-mediated suppression of EGP is preserved in obese men, whereas suppression of VLDL-TG secretion is less pronounced in obese men. Compared with EGP, the inability to achieve suppression of VLDL-TG secretions to a level similar to control subjects during hyperinsulinemia seems to be an early manifestation in male obesity.
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Affiliation(s)
- Lars P. Sørensen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Esben Søndergaard
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Birgitte Nellemann
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Jens S. Christiansen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Lars C. Gormsen
- Department of Nuclear Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Søren Nielsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Corresponding author: Søren Nielsen,
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Sørensen LP, Brock B, Mengel A, Rungby J, Moller N, Nielsen S, Vølund A, Schmitz O. Similarity of pharmacodynamic effects of a single injection of insulin glargine, insulin detemir and NPH insulin on glucose metabolism assessed by 24-h euglycaemic clamp studies in healthy humans. Diabet Med 2010; 27:830-7. [PMID: 20636965 DOI: 10.1111/j.1464-5491.2010.03026.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Two long-acting insulin analogues, insulin glargine and insulin detemir, have been developed as alternatives to neutral protamine Hagedorn (NPH) insulin, which has been the preferred basal insulin preparation for decades. The aim was to directly compare the pharmacodynamic properties of the long-acting insulin analogues and NPH insulin after a single subcutaneous injection. METHODS The study was conducted as a double-blind, controlled, three-arm, crossover study including 10 healthy lean male volunteers. On three different occasions, each subject was challenged with 0.4 U kg(-1) of either insulin glargine, insulin detemir or NPH insulin. Plasma glucose was maintained at 0.3 mmol l(-1) below fasting level by glucose clamping for 24 h. C-peptide, insulin, free fatty acids (FFAs) and counter regulatory hormones were measured throughout the clamp period, whereas endogenous glucose release (EGR) was assessed by isotope dilution technique (3-(3)H-glucose). RESULTS The mean glucose infusion rate (GIR)-time profiles revealed no significant differences between the three preparations in the primary endpoints: Maximal GIR of approximately 3.4 mg kg(-1) min(-1) (P = 0.68), time to maximal GIR of approximately 10 h (TR(max)) (P = 0.35) and area under the GIR curve (GIR(AUC)) (P = 0.81). Compared with the other insulin preparations, EGR (see above)was lower for insulin detemir at the beginning of the clamp period (330-360 min) (P = 0.007) while GIR was lower (P = 0.005) and FFA concentrations were higher (P = 0.005) during the last 4 h of the clamp. CONCLUSIONS In this experimental design, only minor pharmacodynamic differences were demonstrated between insulin detemir, insulin glargine and NPH insulin.
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Affiliation(s)
- L P Sørensen
- Aarhus University Hospital-Department M (Endocrinology and Diabetes), Aarhus, Denmark
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Gjessing PF, Fuskevåg OM, Hagve M, Revhaug A, Irtun Ø. Hyperinsulinemic euglycemic step clamping with tracer glucose infusion and labeled glucose infusate for assessment of acute insulin resistance in pigs. Am J Physiol Endocrinol Metab 2010; 298:E1305-12. [PMID: 20371732 DOI: 10.1152/ajpendo.00701.2009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study aimed to establish hyperinsulinemic euglycemic step clamping with tracer glucose infusion and labeled glucose infusate (step hot-GINF HEC) for assessment of acute insulin resistance in anesthetized pigs and to arrange for combination with invasive investigative methods. Tracer enrichment was measured during D-[6,6-(2)H(2)]glucose infusion before and after surgical instrumentation (n = 8). Insulin dose-response characteristics were determined by two step hot-GINF HEC procedures, with accordingly labeled glucose infusates performed at a total of six insulin infusion rates ranging from 0.2 to 2.0 mU kg(-1) min(-1) (n = 8). Finally, three-step hot-GINF HEC (0.4, 1.2, and 2.0 mU kg(-1) min(-1)) was performed subsequent to major surgical trauma (n = 8). Tracer enrichment, basal glucose kinetics, and circulating levels of C-peptide, cortisol, glucagon, and catecholamines were not influenced by surgical instrumentation. Mean intraindividual coefficient of variance levels for glucose infusion rates and repeatedly measured insulin, glucose, and tracer enrichment indicated stable clamping conditions. Basal and maximal insulin-stimulated glucose utilization was twice as high as in humans at approximately 5.5 and 21 mg kg(-1) min(-1). Surgical trauma elicited pronounced peripheral and moderate hepatic insulin unresponsiveness (45% lower whole body glucose disposal and 19% less suppressed endogenous glucose release) and apparently diminished metabolic insulin clearance. Step hot-GINF HEC seems suitable for assessment of acute insulin resistance in anesthetized pigs, and combination with invasive investigative methods requiring surgical instrumentation can be accomplished without the premises for utilization of the technique being altered, but attention must be paid to alterations in metabolic insulin clearance.
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Glintborg D, Frystyk J, Højlund K, Andersen KK, Henriksen JE, Hermann AP, Hagen C, Flyvbjerg A, Andersen M. Total and high molecular weight (HMW) adiponectin levels and measures of glucose and lipid metabolism following pioglitazone treatment in a randomized placebo-controlled study in polycystic ovary syndrome. Clin Endocrinol (Oxf) 2008; 68:165-74. [PMID: 17803698 DOI: 10.1111/j.1365-2265.2007.03015.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Recent studies suggested that the effect of adiponectin on insulin-stimulated glucose metabolism is mediated primarily by the high molecular weight (HMW) form of adiponectin. In the present study we evaluated total and HMW adiponectin in polycystic ovary syndrome (PCOS) patients and controls and examined possible mechanisms for increased insulin sensitivity during pioglitazone treatment. STUDY SUBJECTS Thirty PCOS patients randomized to pioglitazone, 30 mg/day, or placebo for 16 weeks and 14 weight-matched healthy females were studied. DESIGN Total and HMW adiponectin levels were measured, and euglycaemic hyperinsulinaemic clamps and indirect calorimetry were performed. Delta-values denoted changes during pioglitazone treatment (16 weeks--basal). RESULTS Pretreatment adiponectin levels were decreased in PCOS patients vs. controls (P < 0.05), whereas no significant differences were found in HMW adiponectin levels. Following pioglitazone treatment, total and HMW adiponectin increased (all P < 0.05), whereas no significant changes were observed with placebo. Delta-total adiponectin levels correlated positively with the rate of Delta-insulin-stimulated glucose disposal (R(d)) (r = 0.89) and Delta-oxidative glucose metabolism (r = 0.71) and inversely with Delta-fasting free fatty acid (FFA) levels (r = -0.69) and Delta-lipid oxidation (r = -0.73) during insulin stimulation (all P < 0.01). Weaker correlations were found between Delta-HMW adiponectin levels and Delta-measures of glucose and lipid metabolism during insulin stimulation than with Delta-total adiponectin. CONCLUSION A close correlation between increased total adiponectin levels and increased insulin-stimulated glucose metabolism during pioglitzone treatment supports the hypothesis that the insulin-sensitizing effect of pioglitazone in PCOS is, at least in part, mediated by adiponectin. Measures of changes in HMW adiponectin did not add further information to this relationship.
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Affiliation(s)
- Dorte Glintborg
- Department of Endocrinology and Metabolism, Odense University Hospital, Odense C, Denmark.
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Gjedsted J, Gormsen LC, Nielsen S, Schmitz O, Djurhuus CB, Keiding S, Ørskov H, Tønnesen E, Møller N. Effects of a 3-day fast on regional lipid and glucose metabolism in human skeletal muscle and adipose tissue. Acta Physiol (Oxf) 2007; 191:205-16. [PMID: 17784905 DOI: 10.1111/j.1748-1716.2007.01740.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AIM Fasting is characterized by increased whole body lipolysis and lipid oxidation, decreased glucose oxidation and insulin resistance. To identify the regional sources and underlying mechanisms, we studied 10 healthy male volunteers post-absorptively and after 72 h of fasting. METHODS Each study comprised a 3-h basal period and a 3-h hyperinsulinaemic euglycaemic clamp and we used a combination of leg and forearm arteriovenous techniques, upper and lower body microdialysis and glucose and palmitate tracers. RESULTS In the basal state, plasma levels, fluxes and oxidation rates of free fatty acids all roughly doubled after fasting. Palmitate fluxes across the forearm and leg also increased by two to threefold and interstitial leg muscle glycerol concentrations doubled. Subcutaneous femoral glycerol concentrations and blood flows were unaltered, but abdominal subcutaneous blood flow increased by 50% in the presence of unchanged glycerol concentrations, indicating stimulated abdominal lipolysis. During the clamp, we observed whole body insulin resistance and glucose uptake across the leg and forearm decreased by 60%. CONCLUSION Our data show that fasting induces insulin resistance in upper and lower body muscles and suggest that increased lipolysis, is primarily due to the activation of lipolysis in muscle-associated fat (in the leg) and in upper body subcutaneous fat, whereas peripheral subcutaneous fat is spared.
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Affiliation(s)
- J Gjedsted
- Department of Anaesthesia and Intensive Care Medicine, Aarhus University Hospital, Noerrebrogade, Aarhus, Denmark.
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Glintborg D, Hermann AP, Andersen M, Hagen C, Beck-Nielsen H, Veldhuis JD, Henriksen JE. Effect of pioglitazone on glucose metabolism and luteinizing hormone secretion in women with polycystic ovary syndrome. Fertil Steril 2006; 86:385-97. [PMID: 16782094 DOI: 10.1016/j.fertnstert.2005.12.067] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 12/29/2005] [Accepted: 12/29/2005] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To thoroughly examine the mechanisms for insulin resistance in polycystic ovary syndrome (PCOS) and to evaluate the effects of pioglitazone treatment on insulin resistance, beta-cell function, LH secretion, and glucose metabolism. DESIGN Randomized, blinded, placebo-controlled study. SETTING Outpatient clinic, at a university hospital in Denmark. PATIENT(S) Thirty obese women with PCOS and 14 weight-matched healthy females. INTERVENTION(S) Sixteen weeks of blinded treatment with pioglitazone (30 mg/d) or placebo. MAIN OUTCOME MEASURE(S) Fasting blood samples, 24-hour 20-minute integrated blood sampling (LH, insulin, and C-peptide), euglycemic hyperinsulinemic clamps including 3-(3)H glucose, and indirect calorimetry were performed before and after the intervention period. RESULT(S) Patients with PCOS had significantly lower insulin sensitivity compared with controls, including significantly decreased insulin-stimulated oxidative and nonoxidative glucose metabolism. Pioglitazone treatment resulted in significantly lower levels of fasting insulin and significantly higher insulin sensitivity, increased insulin-stimulated glucose oxidation, and increased insulin-stimulated inhibition of lipid oxidation. During 24-hour blood sampling, significantly lower area under-the-curve insulin and lower median insulin levels were observed. Secretion profiles of LH and E(2) and T levels did not change significantly. CONCLUSION(S) Insulin resistance in PCOS was characterized by hyperinsulinemia, impaired insulin-stimulated oxidative and nonoxidative glucose metabolism, which was partly reversed by pioglitazone treatment.
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Affiliation(s)
- Dorte Glintborg
- Department of Endocrinology and Metabolism, Odense University Hospital, Odense, Denmark.
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Stingl H, Chandramouli V, Schumann WC, Brehm A, Nowotny P, Waldhäusl W, Landau BR, Roden M. Changes in hepatic glycogen cycling during a glucose load in healthy humans. Diabetologia 2006; 49:360-8. [PMID: 16380802 DOI: 10.1007/s00125-005-0099-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 09/19/2005] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS Glycogen cycling, i.e. simultaneous glycogen synthesis and glycogenolysis, affects estimates of glucose fluxes using tracer techniques and may contribute to hyperglycaemia in diabetic conditions. This study presents a new method for quantifying hepatic glycogen cycling in the fed state. Glycogen is synthesised from glucose by the direct and indirect (gluconeogenic) pathways. Since glycogen is also synthesised from glycogen, i.e. glycogen-->glucose 1-phosphate-->glycogen, that synthesised through the direct and indirect pathways does not account for 100% of glycogen synthesis. The percentage contribution of glycogen cycling to glycogen synthesis then equals the difference between the sum of the percentage contributions of the direct and indirect pathways and 100. MATERIALS AND METHODS The indirect and direct pathways were measured independently in nine healthy volunteers who had fasted overnight. They ingested (2)H(2)O (5 ml/kg body water) and were infused with [5-(3)H]glucose and acetaminophen (paracetamol; 1 g) during hyperglycaemic clamps (7.8 mmol/l) lasting 8 h. The percentage contribution of the indirect pathway was calculated from the ratio of (2)H enrichments at carbon 5 to that at carbon 2, and the contribution of the direct pathway was determined from the (3)H-specific activity, relative to plasma glucose, of the urinary glucuronide excreted between 2 and 4, 4 and 6, and 6 and 8 h. RESULTS Glucose infusion rates increased (p<0.01) to approximately 50 mumol kg(-1) min(-1). Plasma insulin and the insulin : glucagon ratio rose approximately 3.6- and approximately 8.3-fold (p<0.001), respectively. From the difference between 100% and the sum of the direct (2-4 h, 54+/-6%; 4-6 h, 59+/-5%; 6-8 h, 63+/-4%) and indirect (32+/-3, 38+/-4, 36+/-3%) pathways, glycogen cycling was seen to be decreased (p<0.05) from 14+/-4% (2-4 h) to 4+/-3% (4-6 h) and 1+/-3% (6-8 h). CONCLUSIONS/INTERPRETATION This method allows measurement of hepatic glycogen cycling in the fed state and demonstrates that glycogen cycling occurs most in the early hours after glucose loading subsequent to a fast.
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Affiliation(s)
- H Stingl
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
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13
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Bryhni B, Jenssen TG, Olafsen K, Bendikssen A. Oxidative and nonoxidative glucose disposal in elderly vs younger men with similar and smaller body mass indices and waist circumferences. Metabolism 2005; 54:748-55. [PMID: 15931609 DOI: 10.1016/j.metabol.2005.01.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Defects in oxidative and nonoxidative glucose metabolism may be involved in the insulin resistance of aging, possibly linked to a central redistribution of body fat. By hyperinsulinemic-euglycemic clamps with whole-body indirect calorimetry, we assessed the contributions of oxidative and nonoxidative glucose disposal to insulin action in 12 elderly persons and 2 groups of younger subjects (14 in each) who had participated in a large population study. Subjects from Young-1 were individually matched to the elderly persons by body mass index and had similar waist circumferences, whereas subjects from Young-2 had a body mass index typical of their age group in the population study and smaller waist measurements. In the combined sample, we also considered possible determinants, related to age and central fat, of flux through these metabolic pathways. The elderly persons had lower nonoxidative glucose disposal compared with the men in Young-2 ( P = .0450 by analysis of variance), whereas glucose oxidation did not differ between the groups. Glucose oxidation correlated negatively with waist circumferences, triglycerides, and alanine aminotransferase and positively with total testosterone and sex hormone-binding globulin. Nonoxidative glucose metabolism correlated inversely with waist circumferences, triglycerides, and free fatty acids and positively with maximum O 2 consumption and total testosterone. In the best regression models, alanine aminotransferase and triglycerides were negatively associated with glucose oxidation (model R 2 = 39%), whereas lower baseline free fatty acids and higher maximum O 2 consumption and sex hormone-binding globulin predicted enhanced nonoxidative glucose metabolism (model R 2 = 47%). These results substantiate that measures to avert abdominal adiposity may prevent insulin resistance and its related metabolic derangements in elderly persons.
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Affiliation(s)
- Bente Bryhni
- Department of Clinical Medicine, University of Tromsø, N-9037 Tromsø, Norway.
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Affiliation(s)
- Peter Staehr
- Department of Endocrinology M, Odense University Hospital, DK-5000, Odense C, Denmark.
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15
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Tripathy D, Eriksson KF, Orho-Melander M, Fredriksson J, Ahlqvist G, Groop L. Parallel manifestation of insulin resistance and beta cell decompensation is compatible with a common defect in Type 2 diabetes. Diabetologia 2004; 47:782-93. [PMID: 15114470 DOI: 10.1007/s00125-004-1393-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Accepted: 01/19/2004] [Indexed: 11/24/2022]
Abstract
AIMS/HYPOTHESIS The aim of the study was to evaluate the relationship between insulin sensitivity, beta cell function and glucose tolerance, and its dependence on variants in the newly identified Type 2 diabetes susceptibility gene, calpain-10 ( CAPN10). METHODS We studied 203 men of the same age but with varying degrees of glucose tolerance. These men participated in (i) an oral glucose tolerance test, (ii) a euglycaemic clamp combined with indirect calorimetry and infusion of [3-(3)H]-glucose and (iii) a stepwise assessment of acute insulin response to arginine (AIR) at three different glucose concentrations (fasting, 14 and 28 mmol/l). RESULTS There was a linear increase in NEFA levels ( p<0.0005) and WHR ( p<0.0005) and decrease in glucose uptake due to a reduction in glucose storage over the entire range of glucose tolerance ( r=-0.404; p<0.005). No increase in endogenous glucose production (EGP) was seen until patients had manifest diabetes. However, when EGP was expressed relative to fasting insulin concentrations, there was a linear deterioration of basal hepatic insulin sensitivity ( r=-0.514; p<0.005). The AIR followed a bell-shaped curve with an initial rise and subsequent decrease. However, AIR adjusted for insulin sensitivity (disposition index) showed a linear decrease with increasing glucose concentrations ( r=-0.563; p<0.001) starting already in subjects with normal glucose tolerance. There was an inverse correlation between increase in WHR and NEFA and peripheral as well as hepatic insulin sensitivity. Subjects with the genotype combination of CAPN10 consisting of SNP44 TT and SNP43 GG genotypes had significantly lower insulin-stimulated glucose uptake than carriers of the other genotype combinations (5.3+/-0.4 vs 7.2+/-0.4 mg.ffm kg(-1).min(-1).mU.l(-1); p<0.005). CONCLUSIONS/INTERPRETATION We conclude that the pre-diabetic state is characterised by a similar linear deterioration of peripheral and hepatic insulin sensitivity as beta cell function and that variants in the CAPN10 gene modify this relationship. These findings are compatible with a common defect in muscle, liver and beta cells in the pathogenesis of Type 2 diabetes.
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Affiliation(s)
- D Tripathy
- Wallenberg Laboratory, Department of Endocrinology, Lund University, Sweden
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16
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Degn KB, Juhl CB, Sturis J, Jakobsen G, Brock B, Chandramouli V, Rungby J, Landau BR, Schmitz O. One week's treatment with the long-acting glucagon-like peptide 1 derivative liraglutide (NN2211) markedly improves 24-h glycemia and alpha- and beta-cell function and reduces endogenous glucose release in patients with type 2 diabetes. Diabetes 2004; 53:1187-94. [PMID: 15111485 DOI: 10.2337/diabetes.53.5.1187] [Citation(s) in RCA: 317] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Glucagon-like peptide 1 (GLP-1) is potentially a very attractive agent for treating type 2 diabetes. We explored the effect of short-term (1 week) treatment with a GLP-1 derivative, liraglutide (NN2211), on 24-h dynamics in glycemia and circulating free fatty acids, islet cell hormone profiles, and gastric emptying during meals using acetaminophen. Furthermore, fasting endogenous glucose release and gluconeogenesis (3-(3)H-glucose infusion and (2)H(2)O ingestion, respectively) were determined, and aspects of pancreatic islet cell function were elucidated on the subsequent day using homeostasis model assessment and first- and second-phase insulin response during a hyperglycemic clamp (plasma glucose approximately 16 mmol/l), and, finally, on top of hyperglycemia, an arginine stimulation test was performed. For accomplishing this, 13 patients with type 2 diabetes were examined in a double-blind, placebo-controlled crossover design. Liraglutide (6 micro g/kg) was administered subcutaneously once daily. Liraglutide significantly reduced the 24-h area under the curve for glucose (P = 0.01) and glucagon (P = 0.04), whereas the area under the curve for circulating free fatty acids was unaltered. Twenty-four-hour insulin secretion rates as assessed by deconvolution of serum C-peptide concentrations were unchanged, indicating a relative increase. Gastric emptying was not influenced at the dose of liraglutide used. Fasting endogenous glucose release was decreased (P = 0.04) as a result of a reduced glycogenolysis (P = 0.01), whereas gluconeogenesis was unaltered. First-phase insulin response and the insulin response to an arginine stimulation test with the presence of hyperglycemia were markedly increased (P < 0.001), whereas the proinsulin/insulin ratio fell (P = 0.001). The disposition index (peak insulin concentration after intravenous bolus of glucose multiplied by insulin sensitivity as assessed by homeostasis model assessment) almost doubled during liraglutide treatment (P < 0.01). Both during hyperglycemia per se and after arginine exposure, the glucagon responses were reduced during liraglutide administration (P < 0.01 and P = 0.01). Thus, 1 week's treatment with a single daily dose of the GLP-1 derivative liraglutide, operating through several different mechanisms including an ameliorated pancreatic islet cell function in individuals with type 2 diabetes, improves glycemic control throughout 24 h of daily living, i.e., prandial and nocturnal periods. This study further emphasizes GLP-1 and its derivatives as a promising novel concept for treatment of type 2 diabetes.
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Affiliation(s)
- Kristine B Degn
- Department of Endocrinology (M & C), University Hospital of Aarhus, AKH, Nørrebrogade 42-44, DK-8000 Aarhus, Denmark
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17
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Poulsen MK, Henriksen JE, Hother-Nielsen O, Beck-Nielsen H. The combined effect of triple therapy with rosiglitazone, metformin, and insulin aspart in type 2 diabetic patients. Diabetes Care 2003; 26:3273-9. [PMID: 14633813 DOI: 10.2337/diacare.26.12.3273] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Type 2 diabetes is caused by reduced insulin secretion and insulin resistance in skeletal muscle and liver. We tested the combination therapy with insulin aspart, rosiglitazone, and metformin with the purpose of treating all three defects in order to test the hypothesis that this "triple therapy" will normalize glucose metabolism. RESEARCH DESIGN AND METHODS Sixteen obese type 2 diabetic outpatients on human NPH or MIX (regular + NPH insulin) insulin twice daily were randomized to either triple therapy, i.e., insulin aspart (a rapid-acting insulin analog) at meals, metformin (which improves hepatic insulin sensitivity), and rosiglitazone (which improves peripheral insulin sensitivity), or to continue their NPH or MIX insulin twice daily for 6 months. Insulin doses were adjusted in both groups based on algorithms. HbA(1c), insulin dose, hypoglycemic episodes, insulin sensitivity (clamp), hepatic glucose production (tracer), and diurnal profiles of plasma glucose and insulin were used in evaluating treatment. RESULTS In the triple therapy group, HbA(1c) declined from 8.8 to 6.8% (P < 0.01) without inducing severe hypoglycemic events. Postprandial hyperglycemia was generally avoided, and the diurnal profile of serum insulin showed fast and high peaks without any need to increase insulin dose. In the control group, the insulin dose was increased by 50%, but nevertheless both HbA(1c) and 24-h blood glucose profiles remained unchanged. Insulin sensitivity improved in both skeletal muscle and the liver in the triple therapy group, whereas no change was observed in the control group. CONCLUSIONS We conclude that treatment of the three major pathophysiological defects in type 2 diabetic subjects by triple therapy significantly improved glucose metabolism in obese type 2 diabetic subjects.
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Staehr P, Hojlund K, Hother-Nielsen O, Holst JJ, Beck-Nielsen H. Does overnight normalization of plasma glucose by insulin infusion affect assessment of glucose metabolism in Type 2 diabetes? Diabet Med 2003; 20:816-22. [PMID: 14510862 DOI: 10.1046/j.1464-5491.2003.01004.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS In order to perform euglycaemic clamp studies in Type 2 diabetic patients, plasma glucose must be reduced to normal levels. This can be done either (i) acutely during the clamp study using high-dose insulin infusion, or (ii) slowly overnight preceding the clamp study using a low-dose insulin infusion. We assessed whether the choice of either of these methods to obtain euglycaemia biases subsequent assessment of glucose metabolism and insulin action. METHODS We studied seven obese Type 2 diabetic patients twice: once with (+ ON) and once without (- ON) prior overnight insulin infusion. Glucose turnover rates were quantified by adjusted primed-constant 3-3H-glucose infusions, and insulin action was assessed in 4-h euglycaemic, hyperinsulinaemic (40 mU m-2 min-1) clamp studies using labelled glucose infusates (Hot-GINF). RESULTS Basal plasma glucose levels (mean +/- sd) were 5.5 +/- 0.5 and 10.7 +/- 2.9 mmol/l in the + ON and - ON studies, respectively, and were clamped at -5.5 mmol/l. Basal rates of glucose production (GP) were similar in the + ON and - ON studies, 83 +/- 13 vs. 85 +/- 14 mg m-2 min-1 (NS), whereas basal rates of glucose disappearance (Rd) were lower in the + ON than in the - ON study, 84 +/- 8 vs. 91 +/- 11 mg m-2 min-1 (P = 0.02). During insulin infusion in the clamp period, rates of GP, 23 +/- 11 vs. 25 +/- 10 mg m-2 min-1, as well as rates of Rd, 133 +/- 32 vs. 139 +/- 37 mg m-2 min-1, were similar in the + ON and - ON studies, respectively (NS). CONCLUSIONS Apart from basal rates of Rd, assessment of glucose turnover rates in euglycaemic clamp studies of Type 2 diabetic patients is not dependent on the method by which plasma glucose levels are lowered.
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Affiliation(s)
- P Staehr
- Diabetes Research Centre, Department of Endocrinology M, Odense University Hospital, Kloevervaenget 4 (3rd floor), DK-5000 Odense C, Denmark.
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19
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Abstract
Several studies have shown that insulin action deteriorates with age, possibly mediated through accumulation of abdominal fat. We determined peripheral insulin action in elderly and younger men who had participated in a large population study (the Tromsø Study). To 15 elderly participants aged 71 to 77 years, we individually matched 15 younger participants aged 31 to 33 years (Y1) by body mass index (BMI). A second young group (Y2) comprised 15 participants also aged 31 to 33 years, but with BMI representative of this age group in the population study. All underwent hyperinsulinemic euglycemic clamps (0.4 mU/kg/min), oral glucose tolerance tests, and determinations of Vo2max. Insulin sensitivity index (ISI=glucose disposal per kg fat-free mass [FFM] divided by steady-state insulin concentration) did not differ between the elderly and Y1, but was higher in Y2 (0.10+/-0.01, 0.12+/-0.01, and 0.17+/-0.02, P=.0011 by analysis of variance [ANOVA]). Adjustment by waist circumferences (analysis of covariance [ANCOVA]) abolished this difference. In univariate analysis of pooled data, ISI correlated negatively to body fat indices, serum triglycerides, and free fatty acids (FFA), and positively to Vo2max. In multiple regression analysis, waist circumference and triglycerides were the only independent predictors of insulin sensitivity, whereas age had no impact. The results confirm that the decline in insulin action seen in elderly people is related to increased abdominal fat rather than aging per se.
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Affiliation(s)
- Bente Bryhni
- Department of Clinical Medicine, University of Tromsø, Norway
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20
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Bailhache E, Ouguerram K, Gayet C, Krempf M, Siliart B, Magot T, Nguyen P. An insulin-resistant hypertriglyceridaemic normotensive obese dog model: assessment of insulin resistance by the euglycaemic hyperinsulinaemic clamp in combination with the stable isotope technique. J Anim Physiol Anim Nutr (Berl) 2003; 87:86-95. [PMID: 14511132 DOI: 10.1046/j.1439-0396.2003.00419.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many studies have shown that in humans insulin resistance (IR) is associated with obesity and hypertriglyceridaemia. The aim of our study was to develop slowly dietary-induced obesity in dogs through long-term overfeeding of a high-fat diet, and to characterize this IR, hypertriglyceridaemic and normotensive model. Insulin resistance was assessed by the euglycaemic hyperinsulinaemic clamp technique. The contribution of hepatic glucose production during the clamp was evaluated using a constant stable-isotope-labelled glucose infusion. Overfeeding a high-fat diet for 7 months was associated with a 43+/-5% body weight increase. Insulin resistance was characterized by hyperinsulinaemia in the unfed state (10+/-1 vs. 24+/-1 microU/ml, in healthy and obese dogs, respectively, p<0.02) and by a reduction of the insulin-mediated glucose uptake (28+/-3 vs. 16+/-1 mg/kg/min, p<0.02). Hepatic glucose production suppression under insulin infusion allowed to conclude that this reduced glucose uptake resulted from a decrease of insulin sensitivity in obese dogs. Furthermore, animals remained normotensive and exhibited a marked hypertriglyceridaemia (0.26+/-0.04 vs. 0.76+/-0.15 mmol/l, in healthy and obese dogs, respectively, p<0.02). Because hypertriglyceridaemia is the most common lipid abnormality in insulin-resistant humans, this dog with slowly induced obesity may constitute a good model to study the consequences of IR in lipid metabolism independently of vascular changes.
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Affiliation(s)
- E Bailhache
- USC INRA de Nutrition et Endocrinologie, Ecole nationale vétérinaire de Nantes, France
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21
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Meneilly GS, McIntosh CHS, Pederson RA, Habener JF, Ehlers MRW, Egan JM, Elahi D. Effect of glucagon-like peptide 1 (7-36 amide) on insulin-mediated glucose uptake in patients with type 1 diabetes. Diabetes Care 2003; 26:837-42. [PMID: 12610046 DOI: 10.2337/diacare.26.3.837] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To examine the insulinomimetic insulin-independent effects of glucagon-like peptide (GLP)-1 on glucose uptake in type 1 diabetic patients. RESEARCH DESIGN AND METHODS We used the hyperinsulinemic-euglycemic clamp (480 pmol. m(-2) x min(-1)) in paired randomized studies of six women and five men with type 1 diabetes. In the course of one of the paired studies, the subjects also received GLP-1 at a dose of 1.5 pmol. kg(-1) x min(-1). The patients were 41 +/- 3 years old with a BMI of 25 +/- 1 kg/m(2). The mean duration of diabetes was 23 +/- 3 years. RESULTS Plasma glucose was allowed to fall from a fasting level of approximately 11 mmol/l to 5.3 mmol/l in each study and thereafter was held stable at that level. Plasma insulin levels during both studies were approximately 900 pmol/l. Plasma C-peptide levels did not change during the studies. In the GLP-1 study, plasma total GLP-1 levels were elevated from the fasting level of 31 +/- 3 to 150 +/- 17 pmol/l. Plasma glucagon levels fell from the fasting levels of approximately 14 pmol/l to 9 pmol/l during both paired studies. Hepatic glucose production was suppressed during the glucose clamps in all studies. Glucose uptake was not different between the two studies ( approximately 40 micromol. kg(-1) x min(-1)). CONCLUSIONS GLP-1 does not augment insulin-mediated glucose uptake in lean type 1 diabetic patients.
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Affiliation(s)
- Graydon S Meneilly
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Staehr P, Hother-Nielsen O, Beck-Nielsen H. Hepatic glucose production: therapeutic target in type 2 diabetes? Diabetes Obes Metab 2002; 4:215-23. [PMID: 12099970 DOI: 10.1046/j.1463-1326.2002.00177.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- P Staehr
- Diabetes Research Centre, Odense University Hospital, Denmark
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23
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Ryan AS, Muller DC, Elahi D. Sequential hyperglycemic-euglycemic clamp to assess beta-cell and peripheral tissue: studies in female athletes. J Appl Physiol (1985) 2001; 91:872-81. [PMID: 11457805 DOI: 10.1152/jappl.2001.91.2.872] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Insulin secretion and rate of utilization (R(d)) of glucose were tested during a newly developed sequential clamp in 42 highly trained female athletes (A; 18-69 yr old) and 14 sedentary control women (C; 18--50 yr old; body mass index <25 kg/m(2)). The A women were categorized into four age groups: 18--29, 30--39, 40--49, and 50--69 yr old. The C women were also grouped by age (18--29 and 40--50 yr old). During the three-step clamp (hyperglycemia, return to euglycemia, and hyperinsulinemia), glucose turnover was assessed with [3-(3)H]glucose. Among the A, the youngest group had the largest first- and second-phase insulin response, which was significantly different from the oldest A (P < 0.05). Among the two C groups, first-phase response of both groups and second-phase response of the older group was higher than respective age-matched A (P < 0.05). During the hyperglycemic period, glucose R(d) was similar among A groups and between A and C. Despite similar levels of insulin between groups during the hyperinsulinemic period (approximately 400 pmol/l), A utilized 36% more glucose than C (P < 0.001). Glucose R(d) was not different across the age groups of A. This newly developed sequential clamp procedure allows assessment of both beta-cell sensitivity to glucose and peripheral tissue sensitivity to insulin in a single session. We have shown that physical activity improves beta-cell efficiency across the age span in women and ameliorates the effect of age on the decline of peripheral tissue sensitivity to insulin.
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Affiliation(s)
- A S Ryan
- Division of Gerontology, Department of Medicine, University of Maryland School of Medicine, and Baltimore Veterans Affairs Medical Center, Baltimore 21201, USA.
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24
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Staehr P, Hother-Nielsen O, Levin K, Holst JJ, Beck-Nielsen H. Assessment of hepatic insulin action in obese type 2 diabetic patients. Diabetes 2001; 50:1363-70. [PMID: 11375337 DOI: 10.2337/diabetes.50.6.1363] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Defects in hepatic insulin action in type 2 diabetes and its possible underlying mechanisms were assessed in euglycemic-hyperinsulinemic clamp studies, using improved tracer methods (constant specific activity technique). Ten obese diabetic patients (age 54 years, BMI 29 +/- 0.5 kg/m(2)) and ten matched control subjects were studied at baseline (after an overnight fast) and during insulin infusions of 20- and 40-mU. m(-2). min(-1). In the diabetic patients, plasma glucose levels were normalized overnight before the studies by low-dose insulin infusion. Hepatic sinusoidal insulin levels were estimated, and plasma levels of free fatty acids (FFAs) and glucagon were determined to assess the direct and indirect effects of insulin on hepatic glucose production (HGP) in type 2 diabetes. Baseline rates of HGP (86 +/- 3 vs. 76 +/- 3 mg. m(-2). min(-1), P < 0.05) were slightly elevated in the diabetic patients compared with control subjects, despite much higher hepatic sinusoidal insulin levels (26 +/- 3 vs. 12 +/- 2 mU/l, P < 0.001). Consequently, a marked defect in the direct (hepatic) effect of insulin on HGP appeared to be present at low insulin levels. However, in response to a small increase in baseline hepatic sinusoidal insulin levels of 11 mU/l (26 +/- 3 to 37 +/- 3 mU/l, P < 0.05) in the 20-mU clamp, a marked suppression of HGP was observed in the diabetic patients (86 +/- 3 to 32 +/- 5 mg. m(-2). min(-1), P < 0.001), despite only minimal changes in FFAs (0.33 +/- 0.05 to 0.25 +/- 0.05 mmol/l, NS) and glucagon (14 +/- 1 to 11 +/- 2 pmol/l, P < 0.05) levels, suggesting that the impairment in the direct effect of insulin can be overcome by a small increase in insulin levels. Compared with control subjects, suppression of HGP in the diabetic patients was slightly impaired in the 20-mU clamp (32 +/- 5 vs. 22 +/- 4 mg. m(-2). min(-1), P < 0.05) but not in the 40-mU clamp (25 +/- 2 vs. 21 +/- 3 mg. m(-2). min(-1), NS). In the 20-mU clamp, hepatic sinusoidal insulin levels in the diabetic patients were comparable with control subjects (37 +/- 3 vs. 36 +/- 3 mU/l, NS), whereas both FFA and glucagon levels were higher (i.e., less suppressed) and correlated with the rates of HGP (R = 0.71, P < 0.02; and R = 0.69, P < 0.05, respectively). Thus, at this insulin level impaired indirect (extrahepatic) effects of insulin seemed to prevail. In conclusion, hepatic insulin resistance is present in obese type 2 diabetic patients but is of quantitative significance only at low physiological insulin levels. Defects in both the direct and the indirect effects of insulin on HGP appear to contribute to this resistance.
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Affiliation(s)
- P Staehr
- Diabetes Research Centre, Medical Department M, Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense C, Denmark.
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25
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Gaster M, Poulsen P, Handberg A, Schroder HD, Beck-Nielsen H. Direct evidence of fiber type-dependent GLUT-4 expression in human skeletal muscle. Am J Physiol Endocrinol Metab 2000; 278:E910-6. [PMID: 10780948 DOI: 10.1152/ajpendo.2000.278.5.e910] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
GLUT-4 expression in individual fibers of human skeletal muscles in younger and older adults was studied. Furthermore, the dependency of insulin-stimulated glucose uptake on fiber type distribution was investigated. Fiber type distribution was determined in cryosections of muscle biopsies from 8 younger (29 yr) and 8 older (64 yr) healthy subjects, and estimates of GLUT-4 expression in individual fibers were obtained by combining immunohistochemistry and stereology. GLUT-4 was more abundantly expressed in slow compared with fast muscle fibers in both younger (P < 0.007) and older (P < 0. 001) subjects. A 25% reduction of GLUT-4 density in fast fibers (P < 0.001) and an unchanged GLUT-4 density in slow fibers were demonstrated in older compared with younger subjects. Insulin-stimulated glucose uptake rates measured by hyperinsulinemic, euglycemic clamp were not correlated with the fraction of slow fibers in the young (r = -0.45, P > 0.25) or in the elderly (r = 0. 11, P > 0.75) subjects. In conclusion, in human skeletal muscle, GLUT-4 expression is fiber type dependent and decreases with age, particularly in fast muscle fibers.
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MESH Headings
- Adult
- Aging
- Biopsy
- Blotting, Western
- Female
- Glucose/metabolism
- Glucose Clamp Technique
- Glucose Tolerance Test
- Glucose Transporter Type 4
- Humans
- Immunohistochemistry
- Insulin/pharmacology
- Male
- Middle Aged
- Monosaccharide Transport Proteins/analysis
- Muscle Fibers, Fast-Twitch/chemistry
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/chemistry
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Proteins
- Muscle, Skeletal/chemistry
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
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Affiliation(s)
- M Gaster
- Departments of Pathology and of Endocrinology, Odense University Hospital, DK-5000 Odense, Denmark.
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Kruszynska YT, Mukherjee R, Jow L, Dana S, Paterniti JR, Olefsky JM. Skeletal muscle peroxisome proliferator- activated receptor-gamma expression in obesity and non- insulin-dependent diabetes mellitus. J Clin Invest 1998; 101:543-8. [PMID: 9449686 PMCID: PMC508596 DOI: 10.1172/jci1076] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
UNLABELLED The two isoforms of peroxisome proliferator-activated receptor-gamma (PPARgamma1 and PPARgamma2), are ligand-activated transcription factors that are the intracellular targets of a new class of insulin sensitizing agents, the thiazolidinediones. The observation that thiazolidinediones enhance skeletal muscle insulin sensitivity in obesity and in patients with non-insulin-dependent diabetes mellitus (NIDDM), by activating PPARgamma, and possibly by inducing its expression, suggests that PPARgamma expression in skeletal muscle plays a key role in determining tissue sensitivity to insulin, and that PPARgamma expression may be decreased in insulin resistant subjects. We used a sensitive ribonuclease protection assay, that permits simultaneous measurement of the two isoforms, to examine the effects of obesity and NIDDM, and the effects of insulin, on skeletal muscle levels of PPARgamma1 and PPARgamma2 mRNA. We studied seven patients with NIDDM (body mass index, 32+/-1 kg/m2), seven lean (24+/-1 kg/m2), and six obese (36+/-1 kg/m2) normal subjects. Biopsies from the vastus lateralis muscle were taken before and after a 5-h hyperinsulinemic (80 mU/m2 per minute) euglycemic clamp. The obese controls and NIDDM patients were insulin resistant with glucose disposal rates during the last 30 min of the clamp that were 67 and 31%, respectively, of those found in the lean controls. PPARgamma1, but not PPARgamma2 mRNA was detected in skeletal muscle at 10-15% of the level found in adipose tissue. No difference was found in PPARgamma1 levels between the three groups, and there was no change in PPARgamma1 levels after 5 h of hyperinsulinemia. In obese subjects, PPARgamma1 correlated with clamp glucose disposal rates (r = 0.92, P < 0.01). In the lean and NIDDM patients, muscle PPARgamma1 levels correlated with percentage body fat (r = 0.76 and r = 0.82, respectively, both P < 0.05) but not with body mass index. IN CONCLUSION (a) skeletal muscle PPARgamma1 expression does not differ between normal and diabetic subjects, and is not induced by short-term hyperinsulinemia; (b) skeletal muscle PPARgamma1 expression was higher in subjects whose percent body fat exceeded 25%, and this may be a compensatory phenomenon in an attempt to maintain normal insulin sensitivity.
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Affiliation(s)
- Y T Kruszynska
- Department of Endocrinology & Metabolism, University of California San Diego, Veterans Administration Center, 3350 La Jolla Village Drive, La Jolla, California 92093, USA
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Mittelman SD, Fu YY, Rebrin K, Steil G, Bergman RN. Indirect effect of insulin to suppress endogenous glucose production is dominant, even with hyperglucagonemia. J Clin Invest 1997; 100:3121-30. [PMID: 9399959 PMCID: PMC508525 DOI: 10.1172/jci119867] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Suppression of endogenous glucose production (EGP) is one of insulin's primary metabolic effects and failure of this action is a major contributor to fasting hyperglycemia of type 2 diabetes mellitus. Classically, insulin was thought to suppress the liver directly, via hyperinsulinemia in the portal vein. Recently, however, we and others have demonstrated that at least part, and possibly most of insulin's action to suppress EGP is normally mediated via an extrahepatic (i.e., indirect) mechanism. We have suggested that this mechanism involves insulin suppression of adipocyte lipolysis, leading to lowered FFA and reduced EGP ("Single Gateway Hypothesis"). Previous studies of the indirect insulin effect from this laboratory were done under conditions of lowered portal glucagon. Because of the possibility that the direct (i.e., portal) effect of insulin may have been underestimated with hypoglucagonemia, these studies examined the relative importance of portal insulin, versus peripheral insulin (administered at one-half the dose to equalize peripheral insulin levels) at four rates of portal glucagon infusion: 0, 0.65 (under-), 1.5 (basal-), and 3.0 ng/kg per min (over-replacement). Portal versus peripheral insulin suppressed steady-state EGP to the same extent (52%), confirming that the primary effect of insulin to suppress EGP is via the peripheral mechanism. This conclusion was maintained regardless of portal glucagonemia, although there was some evidence for an increase in the direct insulin effect at hyperglucagonemia. The indirect effect of insulin is the primary mechanism of steady-state EGP suppression under normal conditions. The direct effect increases with hyperglucagonemia; however, the indirect effect remains predominant even under those conditions.
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Affiliation(s)
- S D Mittelman
- Department of Physiology & Biophysics, University of Southern California School of Medicine, Los Angeles, California 90033, USA
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Andersen UB, Dige-Petersen H, Frandsen EK, Ibsen H, Vølund A. Basal insulin-level oscillations in normotensive individuals with genetic predisposition to essential hypertension exhibit an irregular pattern. J Hypertens 1997; 15:1167-73. [PMID: 9350591 DOI: 10.1097/00004872-199715100-00015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Insulin is secreted in regular pulses at intervals of 12-14 min in normal fasting subjects. An abnormal pattern has been found in subjects with non-insulin-dependent diabetes mellitus (NIDDM) and in young individuals predisposed to NIDDM. It has been suggested that there might be a causal relationship between insulin-secretion abnormalities and insulin resistance. OBJECTIVE To examine whether insulin-secretion abnormalities are also present in offspring of patients with essential hypertension. METHODS Eleven young (aged 18-35 years) normotensive individuals each of whom had two parents with essential hypertension were compared with 10 age- and sex-matched controls each of whom had two normotensive parents. We verified that diabetes and morbid obesity were absent among the subjects and their parents. We studied basal insulin-secretion patterns during a 60 min period, glucose tolerance by administering an oral glucose-tolerance test, insulin resistance by using an isoglycaemic hyperinsulinaemic clamp and basal plasma catecholamine levels. RESULTS Autocorrelation analysis of insulin concentrations showed that the hypertension-prone subjects had a significantly reduced or irregular oscillatory pattern compared with the regular insulin-level oscillations with a period of 12-14 min in control subjects. The hypertension-prone subjects had significantly higher systolic blood pressures and tended to be insulin-resistant. CONCLUSION This is the first evidence of early insulin-secretion abnormalities in young normotensive individuals with a genetic predisposition to essential hypertension, but with a normal glucose tolerance and without a genetic predisposition to NIDDM. Early insulin-secretion abnormalities may be the very first step towards the development of insulin resistance and an important factor initiating the hypertension in hypertension-prone individuals.
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Affiliation(s)
- U B Andersen
- Department of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, Denmark
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Worm D, Vinten J, Staehr P, Henriksen JE, Handberg A, Beck-Nielsen H. Altered basal and insulin-stimulated phosphotyrosine phosphatase (PTPase) activity in skeletal muscle from NIDDM patients compared with control subjects. Diabetologia 1996; 39:1208-14. [PMID: 8897009 DOI: 10.1007/bf02658508] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To measure possible changes in basal and insulin-stimulated phosphotyrosine phosphatase (PTPase) activity in skeletal muscle from insulin-resistant individuals, soluble and particulate muscle fractions were prepared from biopsies taken before and after a 3-h hyperinsulinaemic euglycaemic clamp in eight non-insulin-dependent diabetic (NIDDM) patients and nine control subjects. We used a sensitive sandwich-immunofluorescence assay and the human insulin receptor as the substrate. PTPase activity was expressed as percentage of dephosphorylation of phosphotyrosyl-residues in immobilized insulin receptors per 2 h incubation time per 83 micrograms and 19 micrograms muscle fraction protein (soluble and particulate fraction, respectively). In the diabetic soluble muscle fractions, the basal PTPase activity was decreased compared with that of control subjects (11.5 +/- 5.5 vs 27.5 +/- 3.3, p < 0.04, mean +/- SEM). In the particulate muscle fractions from the control subjects, PTPase activity was increased after 3 h hyperinsulinaemia (20.0 +/- 3.2 vs 30.2 +/- 3.6, p < 0.03) and in the corresponding soluble fractions PTPase activity seemed decreased (27.5 +/- 3.3 vs 19.9 +/- 5.9, NS). No effect of insulin on PTPase activity was found in NIDDM patients (25.1 +/- 4.1 vs 27.2 +/- 5.2, 11.5 +/- 5.5 vs 15.1 +/- 4.5 [particulate and soluble fractions], NS). In conclusion, we found that the basal PTPase activity in soluble muscle fractions was decreased in NIDDM patients; furthermore, insulin stimulation was unable to increase PTPase activities in the particulate fractions, as opposed to the effect of insulin in control subjects.
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Affiliation(s)
- D Worm
- Diabetes Research Centre, Odense University Hospital, Denmark
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Fisher SJ, Shi ZQ, Lickley HL, Efendic S, Vranic M, Giacca A. A moderate decline in specific activity does not lead to an underestimation of hepatic glucose production during a glucose clamp. Metabolism 1996; 45:587-93. [PMID: 8622601 DOI: 10.1016/s0026-0495(96)90028-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have previously shown that modeling errors lead to underestimation of hepatic glucose production (HGP) during glucose clamps when specific activity (SA) declines markedly. We wished to assess whether the failure to keep SA constant substantially affects calculation of HGP during insulin infusion when glucose requirements to maintain the glucose clamp are moderate. Therefore, 150-minute hyperinsulinemic (5.4 pmol - kg (-1) - min (-1) clamps were performed in depancreatized dogs that were maintained hyperglycemic (approximately 10 mmol/L with either (l) unlabeled glucose infusate (COLD Ginf, n = 5) or (2) labeled glucose infusate (HOT Ginf, n = 6) containing high-performance liquid chromatography (HPLC purified [6-3H]glucose. Insulinemia and glucagonemia were similar between the two groups. Additionally, glucose infusion rates were equivalent with COLD and HOT Ginf, indicating comparable insulin effects on overall glucose metabolism. The SA decreased a maximum of 32% with COLD Ginf, but remained constant with HOT Ginf. HGP was suppressed equally with COLD or HOT Ginf treatments at each time point during the clamp (mean suppression during last hour of clamp, 69% +/- 4% and 69% +/- 5%, P = NS, COLD and HOT Ginf, respectively). We conclude that when glucose requirements are moderate and SA changes slowly, as in the diabetic dog, it is not necessary to keep SA perfectly constant to avoid significant modeling errors when calculating HPG during hyperinsulinemic clamps.
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Affiliation(s)
- S J Fisher
- Department of Physiology, University of Toronto, Ontario, Canada
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Henriksen JE, Alford F, Handberg A, Vaag A, Beck-Nielsen H. Glucose processing during the intravenous glucose tolerance test. Metabolism 1996; 45:598-605. [PMID: 8622603 DOI: 10.1016/s0026-0495(96)90030-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The impact of the dynamic changes in plasma glucose and insulin levels observed during a frequently sampled intravenous (IV) glucose tolerance test (FSIGT) on whole-body glucose processing and muscle glycogen metabolism is not known. Paired randomized FSIGTs were performed in eight healthy subjects (age, 31 years; range, 28 to 35; BMI, 25.4 kg/m2; range, 22.3 to 32.1), one with muscle biopsy samples and one without. The mean time average (0- to 40- and 0- to 120-minute) insulin levels during the test were 26.6 and 11.4 mU/1, respectively. Glucose oxidation increased following the IV glucose bolus (basal 1.34 +/- 0.21 v mean value at 0 to 120 minutes 2.09 +/- 0.22 mg/kg fat-free mass [FFM]/min, P < .02). In contrast, fractional glucose-6-phosphate [G-6-P]) (0.1/10 mmol/L) skeletal muscle glycogen synthase activity in muscle biopsies obtained before and following the IV glucose bolus (-30, 30,60, and 120 minutes, respectively) were unchanged (38.1% +/- 2.3%, 38.3% +/- 2.9%, 38.1% +/- 2.3%, 35.4% +/- 2.3%, NS). Skeletal muscle glycogen concentration decreased slightly (449 +/- 54, 439 +/- 55, and 383 +/- 29, and 438 +/- 48 mmol/kg dry weight, P =.05), indicating no net storage of glucose into glycogen during the FSIGT. G-6-P decreased (0.77 +/- 0.08, 0.64 +/- 0.07, 0.66 +/- 0.07, and 0.54 +/- 0.04 mmol/kg dry weight, P < .05). Levels of the insulin-regulatable glucose transporter, GLUT-4, were unchanged. Insulin sensitivity (Si), glucose effectiveness, and insulin secretion parameters (01 and 02) were not affected by the muscle biopsy procedure. In conclusion, the FSIGT is associated predominantly with increased whole-body glucose oxidation with no apparent activation of muscle glucose storage as glycogen. Thus, the Si measured by the FSIGT, although similar in magnitude to the clamp-derived parameter, represents primarily glucose oxidation, in contrast to the euglycemic clamp, which involves glucose oxidation and storage.
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Affiliation(s)
- J E Henriksen
- Diabetes Research Centre, Department of Endocrinology M, Odense University Hospital, Denmark
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Clément K, Pueyo ME, Vaxillaire M, Rakotoambinina B, Thuillier F, Passa P, Froguel P, Robert JJ, Velho G. Assessment of insulin sensitivity in glucokinase-deficient subjects. Diabetologia 1996; 39:82-90. [PMID: 8720607 DOI: 10.1007/bf00400417] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The chronic hyperglycaemia of glucokinase-deficient diabetes results from a glucose-sensing defect in pancreatic beta cells and abnormal hepatic glucose phosphorylation. We have evaluated the contribution of insulin resistance to this form of chronic hyperglycaemia. Insulin sensitivity, assessed by the homeostasis model assessment (HOMA) method in 35 kindreds with glucokinase mutations, was found to be significantly decreased in 125 glucokinase-deficient subjects as compared to 141 unaffected first-degree relatives. Logistic regression analysis showed that in glucokinase-deficient subjects a decrease in insulin sensitivity was associated with deterioration of the glucose tolerance status. A euglycaemic hyperinsulinaemic clamp was performed in 14 glucokinase-deficient subjects and 12 unrelated control subjects. In six patients and six control subjects the clamp was coupled to dideutero-glucose infusion to measure glucose turnover. Average glucose infusion rates (GIR) at 1 and 5 mU.kg body weight.min-1 insulin infusion rates were significantly lower in (the glucokinase-deficient) patients than in control subjects. Although heterogeneous results were observed, in 8 out of the 14 patients GIRs throughout the experiment were lower than 1 SD below the mean of the control subjects. Hepatic glucose production at 1 mU.kg body weight-1.min-1 insulin-infusion rate was significantly higher in patients than in control subjects. In conclusion, insulin resistance correlates with the deterioration of glucose tolerance and contributes to the hyperglycaemia of glucokinase-deficient diabetes. Taken together, our results are most consistent with insulin resistance being considered secondary to the chronic hyperglycaemia and/or hypoinsulinaemia of glucokinase-deficiency. Insulin resistance might also result from interactions between the unbalanced glucose metabolism and susceptibility gene(s) to low insulin sensitivity likely to be present in this population.
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Affiliation(s)
- K Clément
- CNRS EP-10, Institut Pasteur de Lille, France
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Hother-Nielsen O, Henriksen JE, Holst JJ, Beck-Nielsen H. Effects of insulin on glucose turnover rates in vivo: isotope dilution versus constant specific activity technique. Metabolism 1996; 45:82-91. [PMID: 8544782 DOI: 10.1016/s0026-0495(96)90204-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The conventional isotope dilution technique was compared with the more accurate constant specific activity (SA) method at six different insulin levels. Paired euglycemic clamp studies were performed in 30 normal subjects (4-hour insulin infusion: 5, 10, 20, 40, 80, and 160 mU . m-2 . min-1) using primed-constant 3-3H-glucose infusion and either conventional unlabeled glucose infusates (Cold-GINF) or labeled glucose infusates (Hot-GINF) to maintain constant SA. At all insulin levels, both glucose disappearance (Rd) and hepatic glucose production (HGP) were underestimated by the conventional technique, and errors during the first 2 hours correlated with glucose infusion rates (GIRs) (r = .93, P < .00001). During the second hour, mean underestimation of HGP varied from 20% +/- 9% to 84% +/- 16% of basal rates from low-dose to high-dose insulin infusion studies. During prolonged equilibration (3 to 4 hours), errors decreased but were still significant in the two low-dose insulin infusion protocols during the fourth hour. In conclusion, using the conventional isotope dilution technique, suppression of glucose production was overestimated and stimulation of glucose Rd was underestimated, and these errors were greater the higher the GIR. Thus, artifactually greater hepatic and smaller peripheral effects may have been assumed for factors or therapies that influence insulin sensitivity in previous studies using a conventional isotope dilution technique, and therefore, reevaluation of these issues may be relevant in future studies.
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Affiliation(s)
- O Hother-Nielsen
- Department of Medical Endocrinology M, Odense University Hospital, Denmark
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Brun JF, Guintrand-Hugret R, Boegner C, Bouix O, Orsetti A. Influence of short-term submaximal exercise on parameters of glucose assimilation analyzed with the minimal model. Metabolism 1995; 44:833-40. [PMID: 7616840 DOI: 10.1016/0026-0495(95)90234-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
After exercise, glucose uptake in tissues increases by insulin-dependent and -independent mechanisms. We evaluated whether these two effects of exercise on glucose disposal can be detected with the minimal model technique. Seven healthy volunteers were submitted at random order to two frequently sampled intravenous glucose tolerance test (FSIVGTTs), one at rest and the other 25 minutes after a 15-minute exercise test. This exercise included 5 minutes of increasing workload on a cycloergometer followed by 10 minutes at 85% of the maximal theoretic heart rate. Bergman's minimal model of insulin action was used to analyze the two FSIVGTTs and produced the following parameters: coefficient of glucose tolerance (Kg), ie, the slope of the exponential decrease in glycemia between 4 and 19 minutes after intravenous glucose; insulin sensitivity (Sl); and glucose effectiveness at basal insulin (Sg). Sg was divided into its two components: basal insulin effectiveness ([BIE] Sl x basal insulin) and glucose effectiveness at zero insulin ([GEZI] Sg-BIE). After the exercise bout, subjects had an increased Kg (3.44 +/- 0.44 v 2.06 +/- 0.28 x 10(-2).min-1, P < .02), Sl (11.43 +/- 1.27 v 6.23 +/- 0.97 x 10(-4) microU/mL.min-1, P < .01), and Sg (4.40 +/- 0.55 v 2.81 +/- 0.36 x 10(-2).min-1, P < .02). The increase in Sg was mainly explained by a 60% increase in GEZI (3.6 +/- 0.57 v 2.25 +/- 0.36 x 10(-2).min-1, P < .02), but also by an increase in BIE (0.80 +/- 0.12 v 0.47 +/- 0.08 x 10(-2).min-1, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J F Brun
- Prediabetes Unit, Lapeyronie Hospital, Montpellier, France
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Scheen AJ, Paquot N, Castillo MJ, Lefèbvre PJ. How to measure insulin action in vivo. DIABETES/METABOLISM REVIEWS 1994; 10:151-88. [PMID: 7956677 DOI: 10.1002/dmr.5610100206] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- A J Scheen
- Department of Medicine, CHU Liège, Belgium
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Cooney GJ, Storlien LH. Insulin action, thermogenesis and obesity. BAILLIERE'S CLINICAL ENDOCRINOLOGY AND METABOLISM 1994; 8:481-507. [PMID: 7980344 DOI: 10.1016/s0950-351x(05)80283-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The case for obesity per se being a major cause of insulin resistance has been made. There is evidence that each of the control points of insulin on glucose metabolism are negatively influenced by lipid oversupply, a characteristic of the obese state. The answer to the corollary, whether insulin resistance (a universal concomitant of obesity) can in turn lead to obesity via a decrease in thermogenesis, is more complex. Overall, the answer would appear to be no. On a population basis, obese individuals would not appear to have lower metabolic rates, whether expressed on a lean tissue or any other basis, than lean individuals. Even in the subpopulation of hypometabolic obese, there are no convincing data that the reduced metabolic rate is linked to particularly severe insulin resistance. Further, improving insulin action by weight loss would not appear to increase thermogenesis as would be predicted if insulin resistance impaired thermogenesis. A case can be made for reductions in a specific aspect of energy expenditure in obesity, that of meal-induced or glucose-induced thermogenesis, and this may be due to insulin resistance. However, meal-induced thermogenesis is a small component of total energy expenditure and total energy expenditure is not different between lean and obese. That leaves the intriguing possibility that a relative failure of prandial thermogenesis has an impact upon energy balance via impairment of satiety (related to reduced metabolic flux) and thus by increasing intake. While a potentially fruitful research avenue, too few data exist on this possibility for it to be anything more than speculative at this stage.
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Affiliation(s)
- G J Cooney
- Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
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Beck-Nielsen H, Hother-Nielsen O, Vaag A, Alford F. Pathogenesis of type 2 (non-insulin-dependent) diabetes mellitus: the role of skeletal muscle glucose uptake and hepatic glucose production in the development of hyperglycaemia. A critical comment. Diabetologia 1994; 37:217-21. [PMID: 8163059 DOI: 10.1007/s001250050097] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- H Beck-Nielsen
- Department of Internal Medicine M, Odense University Hospital, Denmark
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Earnhardt RC, Kindler DD, Weaver AM, Cornett G, Elahi D, Veldhuis JD, Hanks JB. Hyperinsulinemia after pancreatic transplantation. Prediction by a novel computer model and in vivo verification. Ann Surg 1993; 218:428-41; discussion 441-3. [PMID: 8215635 PMCID: PMC1242995 DOI: 10.1097/00000658-199310000-00004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE The authors evaluated systemic venous insulin release as a cause of the hyperinsulinemia (HNS) associated with pancreatic transplantation (PTX) with respect to the mechanism and metabolic consequences. SUMMARY BACKGROUND DATA Many investigators believe the postoperative anatomy associated with common PTX techniques to be the sole cause of the two- to threefold posttransplantation HINS. However, this concept remains to be conclusively proved and characterized quantitatively. METHODS The authors used three approaches to achieve their objectives. First, a computer model was generated based on established data concerning blood flow and tissue insulin extraction to determine whether it was mathematically possible for HINS to be caused by systemic insulin release. Second, HINS clamps were applied to normal dogs using the Andres clamp technique to quantify the in vivo differences in peripheral insulin levels and the metabolic consequences of systemic versus portal insulin infusion. Third, prolonged insulin half-life was evaluated as a possible mechanism of HINS from systemic insulin release by determination of biexponential rates of plasma disappearance from an endogenous pulse of insulin in surgically induced dog models of systemic and portal insulin release. RESULTS First, the computer model calculated a 1.4- to 2.9-fold increase in peripheral venous insulin levels with systemic versus portal insulin release, verifying mathematically the concept of HINS resulting from systemic insulin release. Second, the actual systemic insulin infusion produced a 1.3- to 1.4-fold increase in peripheral venous insulin levels compared with portal infusion (p < 0.05). No significant differences in hepatic glucose output, total glucose disposal, or glucose infusion requirements were seen. Third, although the basal insulin level was twofold higher in the surgically induced animal models with systemic insulin release (p < 0.003), there were no differences in biexponential insulin clearance parameters. CONCLUSIONS The HINS produced by systemic insulin release did not significantly alter glucose metabolism and was not the result of altered peripheral insulin clearance parameters. In vivo systemic venous insulin infusion studies produce HINS, but not to the degree calculated by mathematic modeling or that occurs after clinical PTX, making it likely that other factors also play a role in the HINS after PTX.
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Affiliation(s)
- R C Earnhardt
- Department of Surgery, University of Virginia Health Sciences Center, Charlottesville
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