scholarly journals Glucose Tolerance and Erythrocyte Insulin Receptors in Friedreich's Ataxia

1979 ◽  
Vol 6 (2) ◽  
pp. 233-239 ◽  
Author(s):  
P. Draper ◽  
D. Shapcott ◽  
A. Larose ◽  
J. Stankova ◽  
F. Levesque ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Glucose Intolerance ◽  
Family Members ◽  
Insulin Response ◽  
Insulin Binding ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
Insulin Metabolism

SummaryDetailed in vivo and in vitro studies of glucose and insulin metabolism in Friedreich's ataxia patients and unaffected family members have further defined the extent of the abnormalities in carbohydrate metabolism. The high incidence of glucose intolerance and a hyper-insulinemic response to a glucose challenge in a high percentage of Friedreich's ataxia patients has been confirmed. An increased incidence of glucose intolerance among hétérozygotes is suggested, while the siblings show a more normal distribution of diabetes and a nearly normal insulin response to the glucose tolerance test. Human growth hormone patterns are normal for all groups.Preliminary studies of insulin binding to erythrocytes suggest a difference in the binding characteristics among diabetic Friedreich's ataxia patients, while the binding in the non-diabetic Friedreich's ataxia group is similar to that of non-diabetic controls. Results from a small group of non-diabetic siblings suggest a normal insulin binding, while a tendency toward increased binding at low insulin concentrations among diabetic family members is noted.

scholarly journals 4-Hydroxyisoleucine: experimental evidence of its insulinotropic and antidiabetic properties

1999 ◽  
Vol 277 (4) ◽  
pp. E617-E623 ◽  
Author(s):  
Christophe Broca ◽  
René Gross ◽  
Pierre Petit ◽  
Yves Sauvaire ◽  
Michèle Manteghetti ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Insulin Response ◽  
Oral Glucose ◽  
Dependent Manner ◽  
Insulin Dependent ◽  
Glucose Tolerance Tests ◽  
Insulin Dependent Diabetic ◽  
Single Intravenous Administration

We have recently shown in vitro that 4-hydroxyisoleucine (4-OH-Ile), an amino acid extracted from fenugreek seeds, potentiates insulin secretion in a glucose-dependent manner. The present study was designed to investigate whether 4-OH-Ile could exert in vivo insulinotropic and antidiabetic properties. For this purpose, intravenous or oral glucose tolerance tests (IVGTTs and OGTTs, respectively) were performed not only in normal animals but also in a type II diabetes rat model. During IVGTT in normal rats or OGTT in normal dogs, 4-OH-Ile (18 mg/kg) improved glucose tolerance. The lactonic form of 4-OH-Ile was ineffective in normal rats. In non-insulin-dependent diabetic (NIDD) rats, a single intravenous administration of 4-OH-Ile (50 mg/kg) partially restored glucose-induced insulin response without affecting glucose tolerance; a 6-day subchronic administration of 4-OH-Ile (50 mg/kg, daily) reduced basal hyperglycemia, decreased basal insulinemia, and slightly, but significantly, improved glucose tolerance. In vitro, 4-OH-Ile (200 μM) potentiated glucose (16.7 mM)-induced insulin release from NIDD rat-isolated islets. So, the antidiabetic effects of 4-OH-Ile on NIDD rats result, at least in part, from a direct pancreatic B cell stimulation.

scholarly journals Disruption of the Dopamine D2 Receptor Impairs Insulin Secretion and Causes Glucose Intolerance

Endocrinology ◽  
2010 ◽  
Vol 151 (4) ◽  
pp. 1441-1450 ◽  
Author(s):  
Isabel García-Tornadú ◽  
Ana M. Ornstein ◽  
Astrid Chamson-Reig ◽  
Michael B. Wheeler ◽  
David J. Hill ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Intolerance ◽  
Dopamine D2 Receptor ◽  
D2 Receptor ◽  
Insulin Response ◽  
Wild Type ◽  
Β Cell ◽  
Insulin Response To Glucose

The relationship between antidopaminergic drugs and glucose has not been extensively studied, even though chronic neuroleptic treatment causes hyperinsulinemia in normal subjects or is associated with diabetes in psychiatric patients. We sought to evaluate dopamine D2 receptor (D2R) participation in pancreatic function. Glucose homeostasis was studied in D2R knockout mice (Drd2−/−) mice and in isolated islets from wild-type and Drd2−/− mice, using different pharmacological tools. Pancreas immunohistochemistry was performed. Drd2−/− male mice exhibited an impairment of insulin response to glucose and high fasting glucose levels and were glucose intolerant. Glucose intolerance resulted from a blunted insulin secretory response, rather than insulin resistance, as shown by glucose-stimulated insulin secretion tests (GSIS) in vivo and in vitro and by a conserved insulin tolerance test in vivo. On the other hand, short-term treatment with cabergoline, a dopamine agonist, resulted in glucose intolerance and decreased insulin response to glucose in wild-type but not in Drd2−/− mice; this effect was partially prevented by haloperidol, a D2R antagonist. In vitro results indicated that GSIS was impaired in islets from Drd2−/− mice and that only in wild-type islets did dopamine inhibit GSIS, an effect that was blocked by a D2R but not a D1R antagonist. Finally, immunohistochemistry showed a diminished pancreatic β-cell mass in Drd2−/− mice and decreased β-cell replication in 2-month-old Drd2−/− mice. Pancreatic D2Rs inhibit glucose-stimulated insulin release. Lack of dopaminergic inhibition throughout development may exert a gradual deteriorating effect on insulin homeostasis, so that eventually glucose intolerance develops.

scholarly journals Pituitary Responses to a Neuroactive Tripeptide (TRH) in Friedreich’s Ataxia Families

1982 ◽  
Vol 9 (2) ◽  
pp. 189-190
Author(s):  
G. Tolis ◽  
A. Mehta ◽  
E. Andermann ◽  
C. Harvey ◽  
A. Barbeau
Keyword(s):  
Glucose Tolerance ◽  
Family Members ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
Oral Glucose ◽  
Thyroid Function Tests ◽  
Hormone Release ◽  
Growth Hormone Release ◽  
Oral Glucose Tolerance ◽  
Thyroid Hormone Levels

ABSTRACT:Oral glucose tolerance, thyroid function tests, as well as thyrotropin, prolactin and growth hormone release after administration of thyrotropin releasing hormone, were evaluated in patients with Friedreich’s ataxia and unaffected family members. Impaired glucose tolerance was found in the majority of family members, affected or not. Thyroid hormone levels and PRL and TSH responses to TRH, were similar in all and normal. However, GH responses to TRH were abnormal in half of the patients, but in none of the unaffected family members. Paradoxical responses to neuropeptides may characterize some Friedreich’s ataxia patients, and may predict the possibility of therapeutic maneuvers with such peptides in these patients.

The Relation Between Glucose Tolerance and Insulin Binding to Circulating Monocytes in Obese Children

PEDIATRICS ◽  
1982 ◽  
Vol 70 (4) ◽  
pp. 633-637
Author(s):  
Kaichi Kida ◽  
Noriyoshi Watanabe ◽  
Yoshiki Fujisawa ◽  
Yoshinori Goto ◽  
Hiroshi Matsuda
Keyword(s):  
Glucose Tolerance ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Tolerance Test ◽  
Quantitative Relation ◽  
Immunoreactive Insulin ◽  
Oral Glucose ◽  
Obese Children

The quantitative relation between insulin binding to circulating monocytes in vitro and glucose tolerance in obese children in vivo is reported. Sixty-one obese children and 11 healthy control children participated in this study. The oral glucose tolerance test (OGTT) was performed by giving them glucose (1.75 gm/kg of body weight), orally in the morning, and the binding of 125I-labeled insulin to circulating monocytes in vitro was measured prior to OGTT. The glucose tolerance expressed by ΣBS (milligrams/100 ml), the sum of the plasma glucose (blood sugar [BS]) values at OGTT, was significantly correlated with the degree of overweight (r = .316, P < .01) and more highly with ΣIRI (microunits per milliliter), the sum of immunoreactive insulin (IRI) values at OGTT (r = .512, P < .001). Insulin binding to monocytes in vitro (picograms/106 cells) was inversely correlated with the degree of overweight (r = -. 687, P < .001). Furthermore, ΣBS was inversely correlated significantly with insulin binding to monocytes in vitro (r = -.435, P < .002). These data suggest that the decrease of insulin receptors might be one cause for the impairment of the glucose tolerance associated with obesity in children.

scholarly journals Effect of a Valine Load Test on Plasma Alpha-Keto Acids in Friedreich Ataxia

1982 ◽  
Vol 9 (2) ◽  
pp. 239-242 ◽  
Author(s):  
A. Barbeau ◽  
M. Bertrand ◽  
R. Bouchard ◽  
G.L. Gauthier ◽  
J.P. Bouchard
Keyword(s):  
General Trend ◽  
Genetic Defect ◽  
Friedreich Ataxia ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
Load Test ◽  
Keto Acids ◽  
Branched Chain

SUMMARY:To test the physiological significance in vivo of our previous in vitro finding of reduced valine dehydrogenase (VDH) activity inpatients with Friedreich’s Ataxia, we subjected ataxic patients and controls to an oral valine load test (1.0g) and measured the levels of branched chain α-keto acids in the plasma for 24 hours. We demonstrated a significantly higher peak for α-keto isovaleric acid in Friedreich’s Ataxia and a general trend towards higher than control values in all other α-keto acids measured, and at all times in the experiment. These changes are compatible with the postulated defect in regulation of the activity of VDH in this illness, but because of their small amplitude, they also indicate that a VDH – deficiency is not the genetic defect in Friedreich’s A taxia.

Glucagon-like peptide-1(7-36)-amide confers glucose sensitivity to previously glucose-incompetent beta-cells in diabetic rats: in vivo and in vitro studies

1997 ◽  
Vol 155 (2) ◽  
pp. 369-376 ◽  
Author(s):  
N Dachicourt ◽  
P Serradas ◽  
D Bailbe ◽  
M Kergoat ◽  
L Doare ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Beta Cells ◽  
Insulin Release ◽  
Insulin Response ◽  
Diabetic Rats ◽  
Insulin Response To Glucose ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

The effects of glucagon-like peptide-1(7-36)-amide (GLP-1) on cAMP content and insulin release were studied in islets isolated from diabetic rats (n0-STZ model) which exhibited impaired glucose-induced insulin release. We first examined the possibility of re-activating the insulin response to glucose in the beta-cells of the diabetic rats using GLP-1 in vitro. In static incubation experiments, GLP-1 amplified cAMP accumulation (by 170%) and glucose-induced insulin release (by 140%) in the diabetic islets to the same extent as in control islets. Using a perifusion procedure, GLP-1 amplified the insulin response to 16.7 mM glucose by diabetic islets and generated a clear biphasic pattern of insulin release. The incremental insulin response to glucose in the presence of GLP-1, although lower than corresponding control values (1.56 +/- 0.37 and 4.53 +/- 0.60 pg/min per ng islet DNA in diabetic and control islets respectively), became similar to that of control islets exposed to 16.7 mM glucose alone (1.09 +/- 0.15 pg/min per ng islet DNA). Since in vitro GLP-1 was found to exert positive effects on the glucose competence of the residual beta-cells in the n0-STZ model. we investigated the therapeutic effect of in vivo GLP-1 administration on glucose tolerance and glucose-induced insulin release by n0-STZ rats. An infusion of GLP-1 (10 ng/min per kg; i.v.) in n0-STZ rats enhanced significantly (P < 0.01) basal plasma insulin levels, and, when combined with an i.v. glucose tolerance and insulin secretion test, it was found to improve (P < 0.05) glucose tolerance and the insulinogenic index, as compared with the respective values of these parameters before GLP-1 treatment.

Insulin Secretion and Glucose Tolerance after Islet Transplantation in Rats with Noninsulin-Dependent Diabetes Induced by Neonatal Streptozotocin

1997 ◽  
Vol 6 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Maria-Angeles Tormo ◽  
Trinidad Leon-Quinto ◽  
Catherine Saulnier ◽  
Danielle Bailbe ◽  
Patricia Serradas ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Insulin Release ◽  
Insulin Response ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Β Cells ◽  
Basal Plasma

The present study was designed to identify in a model of noninsulin-dependent diabetes induced by neonatal streptozotocin (n0-STZ), the long-term consequences of an islet graft upon 1) glucose handling of the recipient and, 2) glucose response of the residual β cells in the recipient pancreas. We have examined, 4 and 8 wk after islet implantation under the kidney capsule of syngeneic diabetic n0-STZ rats, their tolerance to glucose administered in vivo, together with their insulin release in response to glucose in vivo (oral glucose tolerance test) as well as in vitro (perfused pancreas). The results in the islet-grafted n0-STZ rats, were compared to those obtained in nongrafted nondiabetic rats and nongrafted n0-STZ rats. Our study shows that transplanting a limited number (900) of adult islets under the kidney capsule reverses to normal, many parameters of the noninsulin-dependent diabetic state in the n0-STZ rat model: these include body weight, basal plasma glucose in both the nonfasted and postabsorptive states, and basal plasma insulin in the postabsorptive state. Furthermore, tolerance to oral glucose administration was greatly improved in the transplanted rats and it was correlated with restoration of a manifest glucose-induced insulin secretion in vivo as evaluated (ΔI) during an oral glucose tolerance test. Our data clearly show that the insulin response to glucose from the endogenous pancreas of n0-STZ diabetic rat was not really improved by long-term (8 wk) basal normoglycemia. More precisely, we were able to detect a slight but significant improvement of the early phase of insulin release in vitro in response to glucose; however, the overall insulin response remained 15 times lower than the normal one with no reapparance of the late phase of insulin release. After cessation of glucose stimulation in vivo, off-response of insulin, which is also a landmark of the impaired insulin release by the β cells of n0-STZ rats, was still detectable in the perfused pancreas of the transplanted n0-STZ rats. Finally, because the reactivity to glucose of the endogenous residual β cells was not regained, the insulin released in vivo during the oral glucose test in the graft-bearing n0-STZ rats can be attributed mainly to functioning of the grafted islets population. Copyright © 1997 Elsevier Science Inc.

scholarly journals Pyruvate Metabolism in Friedreich's Ataxia

1976 ◽  
Vol 3 (4) ◽  
pp. 379-338 ◽  
Author(s):  
A. Barbea ◽  
R.F. Butterworth ◽  
T. Ngo ◽  
G. Breton ◽  
S. Melançon ◽  
...  
Keyword(s):  
Metabolic Regulation ◽  
Bimodal Distribution ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
In Vivo Tests ◽  
Show Evidence ◽  
Lipoamide Dehydrogenase ◽  
Prolonged Response

SUMMARY:Friedreich's ataxia patients show evidence of an abnormally elevated and prolonged response of pyruvate and lactate to a glucose load, with normal fasting levels. However, there is a bimodal distribution of this response with high and low pyruvate responders. This trait appears to be determined genetically, However, although in vivo tests suggest low oxidation of pyruvate, we were unable to confirm any in vitro impairment of each of the components of the pyruvate dehydrogenase (PDH) complex. We conclude that the defect is in the metabolic regulation of PDH, probably at the E3 (lipoamide dehydrogenase) step.

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