scholarly journals Tracing Fasting Glucose Fluxes with Unstressed Catheter Approach in Streptozotocin Induced Diabetic Rats

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Shichun Du ◽  
Hui Wu ◽  
Xiao Xu ◽  
Ying Meng ◽  
Fangzhen Xia ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Glucose Production ◽  
Diabetic Rats ◽  
Endogenous Glucose Production ◽  
Tracer Injection ◽  
Skeletal Muscle Glucose Uptake ◽  
Endogenous Glucose

Objective. Blood glucose concentrations of type 1 diabetic rats are vulnerable, especially to stress and trauma. The present study aimed to investigate the fasting endogenous glucose production and skeletal muscle glucose uptake of Streptozotocin induced type 1 diabetic rats using an unstressed vein and artery implantation of catheters at the tails of the rats as a platform.Research Design and Methods. Streptozotocin (65 mg·kg−1) was administered to induce type 1 diabetic state. The unstressed approach of catheters of vein and artery at the tails of the rats was established before the isotope tracer injection. Dynamic measurement of fasting endogenous glucose production was assessed by continuously infusing stable isotope [6, 6-2H2] glucose, while skeletal muscle glucose uptake by bolus injecting radioactively labeled [1-14C]-2-deoxy-glucose.Results. Streptozotocin induced type 1 diabetic rats displayed polydipsia, polyphagia, and polyuria along with overt hyperglycemia and hypoinsulinemia. They also had enhanced fasting endogenous glucose production and reduced glucose uptake in skeletal muscle compared to nondiabetic rats.Conclusions. The dual catheters implantation at the tails of the rats together with isotope tracers injection is a save time, unstressed, and feasible approach to explore the glucose metabolism in animal models in vivo.

scholarly journals Effects of Growth Hormone and Free Fatty Acids on Insulin Sensitivity in Patients with Type 1 Diabetes

2009 ◽  
Vol 94 (9) ◽  
pp. 3297-3305 ◽  
Author(s):  
Burak Salgin ◽  
Maria L. Marcovecchio ◽  
Rachel M. Williams ◽  
Sarah J. Jackson ◽  
Leslie J. Bluck ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acids ◽  
Growth Hormone ◽  
Type 1 Diabetes ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Endogenous Glucose

Context: Because GH stimulates lipolysis, an increase in circulating free fatty acid levels, as opposed to a direct effect of high GH levels, could underlie the development of insulin resistance in type 1 diabetes (T1D). Our aim was to explore the relative contributions of GH and free fatty acids to the development of insulin resistance in patients with T1D. Patients: Seven (four females, three males) nonobese patients with T1D aged 21–30 yr were studied on four occasions in random order. On each visit, overnight endogenous GH production was suppressed by octreotide. Three 1-h pulses of recombinant human GH (rhGH) or placebo were administered on two visits each. Acipimox, an antilipolytic drug, or a placebo were ingested every 4 h on two visits each. Stable glucose and glycerol isotopes were used to assess glucose and glycerol turnover. The overnight protocol was concluded by a two-step hyperinsulinemic euglycemic clamp on each visit. Main Outcome: rhGH administration led to increases in the insulin infusion rate required to maintain euglycemia overnight (P = 0.008), elevated basal endogenous glucose production (P = 0.007), decreased basal peripheral glucose uptake (P = 0.03), and reduced glucose uptake during step 1 of the clamp (P < 0.0001). Coadministration of rhGH and acipimox reversed these effects and suppression of lipolysis in the absence of GH replacement led to further increases in insulin sensitivity. Results: GH pulses were associated with an increase in endogenous glucose production and decreased rates of peripheral glucose uptake, which was entirely reversed by acipimox. Therefore, GH-driven decreases in insulin sensitivity are mainly determined by the effect of GH on lipolysis. Growth hormone decreases insulin sensitivity through increases in free fatty acid levels.

scholarly journals Improvement in Insulin Sensitivity After Human Islet Transplantation for Type 1 Diabetes

2013 ◽  
Vol 98 (11) ◽  
pp. E1780-E1785 ◽  
Author(s):  
Michael R. Rickels ◽  
Stephanie M. Kong ◽  
Carissa Fuller ◽  
Cornelia Dalton-Bakes ◽  
Jane F. Ferguson ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Islet Transplantation ◽  
Low Dose ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Induce Insulin Resistance ◽  
Endogenous Glucose

Context: Islet transplantation can improve metabolic control for type 1 diabetes (T1D), an effect anticipated to improve insulin sensitivity. However, current immunosuppression regimens containing tacrolimus and sirolimus have been shown to induce insulin resistance in rodents. Objective: The objective of the study was to evaluate the effect of islet transplantation on insulin sensitivity in T1D using euglycemic clamps with the isotopic dilution method to distinguish between effects at the liver and skeletal muscle. Design, Setting, and Participants: Twelve T1D subjects underwent evaluation in the Clinical and Translational Research Center before and between 6 and 7 months after the transplant and were compared with normal control subjects. Intervention: The intervention included intrahepatic islet transplantation according to a Clinical Islet Transplantation Consortium protocol under low-dose tacrolimus and sirolimus immunosuppression. Main Outcome Measures: Total body (M/Δinsulin), hepatic (1/endogenous glucose production ·basal insulin) and peripheral [(Rd − endogenous glucose production)/Δinsulin] insulin sensitivity assessed by hyperinsulinemic (1 mU·kg−1·min−1) euglycemic (∼90 mg/dL) clamps with 6,6-2H2-glucose tracer infusion were measured. Results: Glycosylated hemoglobin was reduced in the transplant recipients from 7.0% ± 0.3% to 5.6% ± 0.1% (P < .01). There were increases in total (0.11 ± 0.01 to 0.15 ± 0.02 dL/min·kg per microunit per milliliter), hepatic [2.3 ± 0.1 to 3.7 ± 0.4 × 102 ([milligrams per kilogram per minute]−1·(microunits per milliliter)−1)], and peripheral (0.08 ± 0.01 to 0.12 ± 0.02 dL/min·kg per microunit per milliliter) insulin sensitivity from before to after transplantation (P < .05 for all). All insulin sensitivity measures were less than normal in T1D before (P ≤ .05) and not different from normal after transplantation. Conclusions: Islet transplantation results in improved insulin sensitivity mediated by effects at both the liver and skeletal muscle. Modern dosing of glucocorticoid-free immunosuppression with low-dose tacrolimus and sirolimus does not induce insulin resistance in this population.

691-P: Exercise Effect on Endogenous Glucose Production in Type 1 Diabetes: A Modeling Analysis

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 691-P
Author(s):  
DAVIDE ROMERES ◽  
MICHELE SCHIAVON ◽  
ROBERTO VISENTIN ◽  
ANANDA BASU ◽  
CLAUDIO COBELLI ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Modeling Analysis ◽  
Exercise Effect ◽  
Endogenous Glucose

scholarly journals Glucagon sensitivity and clearance in type 1 diabetes: insights from in vivo and in silico experiments

2015 ◽  
Vol 309 (5) ◽  
pp. E474-E486 ◽  
Author(s):  
Ling Hinshaw ◽  
Ashwini Mallad ◽  
Chiara Dalla Man ◽  
Rita Basu ◽  
Claudio Cobelli ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
In Silico ◽  
Artificial Pancreas ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Action Model ◽  
The Difference ◽  
Hormone Control

Glucagon use in artificial pancreas for type 1 diabetes (T1D) is being explored for prevention and rescue from hypoglycemia. However, the relationship between glucagon stimulation of endogenous glucose production (EGP) viz., hepatic glucagon sensitivity, and prevailing glucose concentrations has not been examined. To test the hypothesis that glucagon sensitivity is increased at hypoglycemia vs. euglycemia, we studied 29 subjects with T1D randomized to a hypoglycemia or euglycemia clamp. Each subject was studied at three glucagon doses at euglycemia or hypoglycemia, with EGP measured by isotope dilution technique. The peak EGP increments and the integrated EGP response increased with increasing glucagon dose during euglycemia and hypoglycemia. However, the difference in dose response based on glycemia was not significant despite higher catecholamine concentrations in the hypoglycemia group. Knowledge of glucagon's effects on EGP was used to develop an in silico glucagon action model. The model-derived output fitted the obtained data at both euglycemia and hypoglycemia for all glucagon doses tested. Glucagon clearance did not differ between glucagon doses studied in both groups. Therefore, the glucagon controller of a dual hormone control system may not need to adjust glucagon sensitivity, and hence glucagon dosing, based on glucose concentrations during euglycemia and hypoglycemia.

IL-6 is not essential for exercise-induced increases in glucose uptake

2013 ◽  
Vol 114 (9) ◽  
pp. 1151-1157 ◽  
Author(s):  
Hayley M. O'Neill ◽  
Rengasamy Palanivel ◽  
David C. Wright ◽  
Tara MacDonald ◽  
James S. Lally ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Steady State ◽  
Glucose Uptake ◽  
Substrate Utilization ◽  
Treadmill Running ◽  
Glucose Clearance ◽  
Skeletal Muscle Glucose Uptake ◽  
Exercise Induced ◽  
Similar Body

Interleukin-6 (IL-6) increases glucose uptake in resting skeletal muscle. IL-6 is released from skeletal muscle during exercise; however; it is not known whether this IL-6 response is important for exercise-induced increases in skeletal muscle glucose uptake. We report that IL-6 knockout (KO) mice, 4 mo of age, have similar body weight to wild-type (WT), and, under resting conditions, oxygen consumption, food intake, substrate utilization, glucose tolerance, and insulin sensitivity are not different. Maximal exercise capacity is also similar to WT. We investigated substrate utilization and glucose clearance in vivo during steady-state treadmill running at 70% of maximal running speed and found that WT and IL-6 KO mice had similar rates of substrate utilization, muscle glucose clearance, and phosphorylation of AMP-activated protein kinase T172. These data provide evidence that IL-6 does not play a major role in regulating substrate utilization or skeletal muscle glucose uptake during steady-state endurance exercise.

scholarly journals Hormone-independent activation of EGP during hypoglycemia is absent in type 1 diabetes mellitus

2000 ◽  
Vol 278 (3) ◽  
pp. E421-E429 ◽  
Author(s):  
Michèle Mevorach ◽  
Jonathan Kaplan ◽  
Chee Jen Chang ◽  
Luciano Rossetti ◽  
Harry Shamoon
Keyword(s):  
Diabetes Mellitus ◽  
Growth Hormone ◽  
Glucose Production ◽  
Glucagon Secretion ◽  
Endogenous Glucose Production ◽  
Experimental Protocol ◽  
Lower Plasma ◽  
The Face ◽  
Endogenous Glucose

It has been suggested that insulin-induced suppression of endogenous glucose production (EGP) may be counteracted independently of increased epinephrine (Epi) or glucagon during moderate hypoglycemia. We examined EGP in nondiabetic ( n = 12) and type 1 diabetic (DM1, n = 8) subjects while lowering plasma glucose (PG) from clamped euglycemia (5.6 mmol/l) to values just above the threshold for Epi and glucagon secretion (3.9 mmol/l). Individualized doses of insulin were infused to maintain euglycemia during pancreatic clamps by use of somatostatin (250 μg/h), glucagon (1.0 ng ⋅ kg− 1 ⋅ min− 1), and growth hormone (GH) (3.0 ng ⋅ kg− 1 ⋅ min− 1) infusions without need for exogenons glucose. Then, to achieve physiological hyperinsulinemia (HIns), insulin infusions were fixed at 20% above the rate previously determined for each subject. In nondiabetic subjects, PG was reduced from 5.4 ± 0.1 mmol/l to 3.9 ± 0.1 mmol/l in the experimental protocol, whereas it was held constant (5.3 ± 0.2 mmol/l and 5.5 mmol/l) in control studies. In the latter, EGP (estimated by [3-3H]glucose) fell to values 40% of basal ( P < 0.01). In contrast, in the experimental protocol, at comparable HIns but with PG at 3.9 ± 0.1 mmol/l, EGP was activated to values about twofold higher than in the euglycemic control ( P < 0.01). In DM1 subjects, EGP failed to increase in the face of HIns and PG = 3.9 ± 0.1 mmol/l. The decrease from basal EGP in DM1 subjects (4.4 ± 1.0 μmol ⋅ kg− 1 ⋅ min− 1) was nearly twofold that in nondiabetics (2.5 ± 0.8 μmol ⋅ kg− 1 ⋅ min− 1, P < 0.02). When PG was lowered further to frank hypoglycemia (∼3.1 mmol/l), the failure of EGP activation in DM1 subjects was even more profound but associated with a 50% lower plasma Epi response ( P < 0.02) compared with nondiabetics. We conclude that glucagon- or epinephrine-independent activation of EGP may accompany other counterregulatory mechanisms during mild hypoglycemia in humans and is impaired or absent in DM1.

scholarly journals Long-Term Improvement in Glucose Control and Counterregulation by Islet Transplantation for Type 1 Diabetes

2016 ◽  
Vol 101 (11) ◽  
pp. 4421-4430 ◽  
Author(s):  
Michael R. Rickels ◽  
Amy J. Peleckis ◽  
Eileen Markmann ◽  
Cornelia Dalton-Bakes ◽  
Stephanie M. Kong ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Islet Transplantation ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
University Of Pennsylvania ◽  
Symptom Recognition ◽  
Endogenous Glucose ◽  
The University

Context: Islet transplantation has been shown to improve glucose counterregulation and hypoglycemia symptom recognition in patients with type 1 diabetes (T1D) complicated by severe hypoglycemia episodes and symptom unawareness, but long-term data are lacking. Objective: To assess the long-term durability of glucose counterregulation and hypoglycemia symptom responses 18 months after intrahepatic islet transplantation and associated measures of glycemic control during a 24-month follow-up period. Design, Setting, and Participants: Ten patients with T1D disease duration of approximately 27 years were studied longitudinally before and 6 and 18 months after transplant in the Clinical & Translational Research Center of the University of Pennsylvania and were compared to 10 nondiabetic control subjects. Intervention: All 10 patients underwent intrahepatic islet transplantation according to the CIT07 protocol at the Hospital of the University of Pennsylvania. Main Outcome Measures: Counterregulatory hormone, endogenous glucose production, and autonomic symptom responses derived from stepped hyperinsulinemic-hypoglycemic and paired hyperinsulinemic-euglycemic clamps with infusion of 6,6-2H2-glucose. Results: Near-normal glycemia (HbA1c ≤ 6.5%; time 70–180 mg/dL ≥ 95%) was maintained for 24 months in all patients, with one returning to low-dose insulin therapy. In response to insulin-induced hypoglycemia, glucagon secretion was incompletely restored at 6 and 18 months, epinephrine was improved at 6 months and normalized at 18 months, and endogenous glucose production and symptoms, absent before, were normalized at 6 and 18 months after transplant. Conclusions: In patients with T1D experiencing problematic hypoglycemia, intrahepatic islet transplantation can lead to long-term improvement of glucose counterregulation and hypoglycemia symptom recognition, physiological effects that likely contribute to glycemic stability after transplant.

Alterations in carbohydrate metabolism in response to short-term dietary carbohydrate restriction

2005 ◽  
Vol 289 (2) ◽  
pp. E306-E312 ◽  
Author(s):  
Matthew P. Harber ◽  
Simon Schenk ◽  
Ariel L. Barkan ◽  
Jeffrey F. Horowitz
Keyword(s):  
Glucose Uptake ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Carbohydrate Oxidation ◽  
Metabolic Effects ◽  
Glucose Disposal ◽  
Carbohydrate Restriction ◽  
Dietary Carbohydrate ◽  
Endogenous Glucose ◽  
Glucose Availability

Dietary carbohydrate restriction (CR) presents a challenge to glucose homeostasis. Despite the popularity of CR diets, little is known regarding the metabolic effects of CR. The purpose of this study was to examine changes in whole body carbohydrate oxidation, glucose availability, endogenous glucose production, and peripheral glucose uptake after dietary CR, without the confounding influence of a negative energy balance. Postabsorptive rates of glucose appearance in plasma (Ra; i.e., endogenous glucose production) and disappearance from plasma (Rd; i.e., glucose uptake) were measured using isotope dilution methods after a conventional diet [60% carbohydrate (CHO), 30% fat, and 10% protein; kcals = 1.3 × resting energy expenditure (REE)] and after 2 days and 7 days of CR (5% CHO, 60% fat, and 35% protein; kcals = 1.3 × REE) in eight subjects (means ± SE; 29 ± 4 yr; BMI 24 ± 1 kg/m2) during a 9-day hospital visit. Postabsorptive plasma glucose concentration was reduced ( P = 0.01) after 2 days but returned to prediet levels the next day and remained at euglycemic levels throughout the diet (5.1 ± 0.2, 4.3 ± 0.3, and 4.8 ± 0.4 mmol/l for prediet, 2 days and 7 days, respectively). Glucose Ra and glucose Rd were reduced to below prediet levels (9.8 ± 0.6 μmol·kg−1·min−1) after 2 days of CR (7.9 ± 0.3 μmol·kg−1·min−1) and remained suppressed after 7 days (8.3 ± 0.4 μmol·kg−1·min−1; both P < 0.001). A greater suppression in carbohydrate oxidation, compared with the reduction in glucose Rd, led to an increased (all P ≤ 0.05) rate of nonoxidative glucose disposal at 7 days (5.2 ± 0.5 μmol·kg−1·min−1), compared with 2 days (2.7 ± 0.5 μmol·kg−1·min−1) and prediet (1.6 ± 0.8 μmol·kg−1·min−1). In response to eucaloric CR, a marked increase in nonoxidative glucose disposal may help maintain systemic glucose availability.

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