CRNT93 said:
If Fonz can back up what he is saying I'll be
happy to hear it.
Oct.2001, I see........
Oh well. You sound very naive. Nearly all
supplement companies twist the data
to make their supplements look better.
Anyways, since I'm in Spain at the moment
I have access to my 5GB removable HD
which is absolutely full of studies about pretty
much everything.
So here goes, you might actually learn something cionstructive
today.
1: Am J Physiol 1997 Jul;273(1 Pt 1):E185-91 Related Articles, LinkOut, Books
Differential effects of lipoic acid stereoisomers on glucose metabolism in insulin-resistant skeletal muscle.
Streeper RS, Henriksen EJ, Jacob S, Hokama JY, Fogt DL, Tritschler HJ.
Department of Physiology, University of Arizona, Tucson 85721-0093, USA.
The racemic mixture of the antioxidant alpha-lipoic acid (ALA) enhances insulin-stimulated glucose metabolism in insulin-resistant humans and animals. We determined the individual effects of the pure R-(+) and S-(-) enantiomers of ALA on glucose metabolism in skeletal muscle of an animal model of insulin resistance, hyperinsulinemia, and dyslipidemia:
R-(+) ALA is the common stereo-isomer used in all
Lipoic acid products btw.
the obese Zucker (fa/fa) rat. Obese rats were treated intraperitoneally acutely (100 mg/kg body wt for 1 h) or chronically [10 days with 30 mg/kg of R-(+)-ALA or 50 mg/kg of S-
Geee........30mg/Kg Thats 3000mg for a 100kg BB'er.
(-)-ALA]. Glucose transport [2-deoxyglucose (2-DG) uptake], glycogen synthesis, and glucose oxidation were determined in the epitrochlearis muscles in the absence or presence of insulin (13.3 nM). Acutely, R-(+)-ALA increased insulin-mediated 2-DG-uptake by 64% (P < 0.05), whereas S-(-)-ALA had no significant effect. Although chronic R-(+)-ALA treatment significantly reduced plasma insulin (17%) and free fatty acids (FFA; 35%) relative to vehicle-treated obese animals, S-(-)-ALA treatment further increased insulin (15%) and had no effect on FFA. Insulin-stimulated 2-DG uptake was increased by 65% by chronic R-(+)-ALA treatment, whereas S-(-)-ALA administration resulted in only a 29% improvement. Chronic R-(+)-ALA treatment elicited a 26% increase in insulin-stimulated glycogen synthesis and a 33% enhancement of insulin-stimulated glucose oxidation. No significant increase in these parameters was observed after S-(-)-ALA treatment. Glucose transporter (GLUT-4) protein was unchanged after chronic R-(+)-ALA treatment but was reduced to 81 +/- 6% of obese control with S-(-)-ALA treatment. Therefore, chronic parenteral treatment with the antioxidant ALA enhances insulin-stimulated glucose transport and non-oxidative and oxidative glucose metabolism in insulin-resistant rat skeletal muscle, with the R-(+) enantiomer being much more effective than the S-(-) enantiomer.
PMID: 9252495 [PubMed - indexed for MEDLINE]
Now, here's the correlation between ALA and carb-intake
(Which raises insulin levels)
1: Life Sci 1997;61(8):805-12 Related Articles, Books, LinkOut
Stimulation by alpha-lipoic acid of glucose transport activity in skeletal muscle of lean and obese Zucker rats.
Henriksen EJ, Jacob S, Streeper RS, Fogt DL, Hokama JY, Tritschler HJ.
Department of Physiology, University of Arizona, Tucson 85721-0093, USA.
[email protected]
Alpha-lipoic acid (ALA), a potent biological antioxidant, improves insulin action of skeletal muscle glucose transport and metabolism in both human and animal models of insulin resistance. In order to obtain further insight into the potential intracellular mechanisms for the action of ALA on insulin-stimulated glucose transport in skeletal muscle, we investigated the effects of direct incubation with ALA (2 mM) on 2-deoxyglucose (2-DG) uptake by epitrochlearis muscle from either insulin-sensitive lean (Fa/-) or insulin-resistant obese (fa/fa) Zucker rats. ALA stimulated 2-DG uptake in muscle of lean animals by 76%, whereas ALA stimulated 2-DG uptake by only 48% in muscle from obese animals. The stimulation of 2-DG uptake due to ALA was enhanced 30-55% in the presence of insulin. In contrast, ALA action on 2-DG uptake was not additive with the effects of electrically-stimulated muscle contractions in either insulin-sensitive or insulin-resistant muscle. Wortmannin (1 microM), an inhibitor of phosphotidylinositol-3-kinase, completely inhibited insulin action on 2-DG uptake, but inhibited ALA action by only 25%.
And the point is:
Collectively, these results indicate that although a portion of ALA action on glucose transport in mammalian skeletal muscle is mediated via the insulin signal transduction pathway, the majority of the direct effect of ALA on skeletal muscle glucose transport is insulin-independent.
Stress on the INSULIN-DEPENDENT.....
PMID: 9275010 [PubMed - indexed for MEDLINE]
And another regarding MAXIMUM THERAPEUTIC LEVEL...
1: Diabetes 1996 Aug;45(8):1024-9 Related Articles, LinkOut, Books
The antioxidant alpha-lipoic acid enhances insulin-stimulated glucose metabolism in insulin-resistant rat skeletal muscle.
Jacob S, Streeper RS, Fogt DL, Hokama JY, Tritschler HJ, Dietze GJ, Henriksen EJ.
Department of Physiology, University of Arizona College of Medicine, Tucson, USA.
Insulin resistance of muscle glucose metabolism is a hallmark of NIDDM. The obese Zucker (fa/fa) rat--an animal model of muscle insulin resistance--was used to test whether acute (100 mg/kg body wt for 1 h) and chronic (5-100 mg/kg for 10 days) parenteral treatments with a racemic mixture of the antioxidant alpha-lipoic acid (ALA) could improve glucose metabolism in insulin-resistant skeletal muscle. Glucose transport activity (assessed by net 2-deoxyglucose [2-DG] uptake), net glycogen synthesis, and glucose oxidation were determined in the isolated epitrochlearis muscles in the absence or presence of insulin (13.3 nmol/l). Severe insulin resistance of 2-DG uptake, glycogen synthesis, and glucose oxidation was observed in muscle from the vehicle-treated obese rats compared with muscle from vehicle-treated lean (Fa/-) rats.
Here it comes.....
Acute and chronic treatments (30 mg.kg-1.day-1, a maximally effective dose) with ALA significantly (P < 0.05) improved insulin-mediated 2-DG uptake in epitrochlearis muscles from the obese
Thats 30mg/Kg again.....
rats by 62 and 64%, respectively. Chronic ALA treatment increased both insulin-stimulated glucose oxidation (33%) and glycogen synthesis (38%) and was associated with a significantly greater (21%) in vivo muscle glycogen concentration. These adaptive responses after chronic ALA administration were also associated with significantly lower (15-17%) plasma levels of insulin and free fatty acids. No significant effects on glucose transporter (GLUT4) protein level or on the activities of hexokinase and citrate synthase were observed. Collectively, these findings indicate that parenteral administration of the antioxidant ALA significantly enhances the capacity of the insulin-stimulatable glucose transport system and of both oxidative and nonoxidative pathways of glucose metabolism in insulin-resistant rat skeletal muscle.
PMID: 8690147 [PubMed - indexed for MEDLINE]
And for future reading..........which just might be
the next generation of glucose disposal type
products.
1: Antioxid Redox Signal 1999 Winter;1(4):523-35 Related Articles, Books
Metabolic effects of gamma-linolenic acid-alpha-lipoic acid conjugate in streptozotocin diabetic rats.
Khamaisi M, Rudich A, Beeri I, Pessler D, Friger M, Gavrilov V, Tritschler H, Bashan N.
Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Data suggesting the involvement of increased oxidative stress in the pathophysiology of diabetes has raised interest in the potential therapeutic benefit of antioxidants. Although beneficial metabolic effects of antioxidant supplementation have been suggested, an antioxidant mode of action, particularly in skeletal muscle, has not been documented. In the present study, we evaluate the metabolic effects of a gamma-linolenic acid-alpha-lipoic acid conjugate (GLA-LA) in streptozotocin-induced diabetic rats, and assess its potential mode of action by comparing its effects with equimolar administration of LA and GLA alone. Ten days of oral supplementation of 20 mg/kg body weight GLA-LA, but not LA or GLA alone, caused a mild reduction in fasting blood glucose concentration as compared with vehicle-treated diabetic rats (375 +/- 11 vs. 416 +/- 16 mg/dl, p = 0.03), with no change in fasting plasma insulin levels. A peripheral insulin-sensitizing effect could be observed with GLA-LA, LA, and GLA treatments, as demonstrated by a significant (p < 0.04) 23%, 13%, and 10% reduction, respectively, in the area under the glucose curve following an intravenous insulin tolerance test. This effect was associated with a 67% and 50% increase in GLUT4 protein content in the membranes of gastrocnemius muscle of GLA-LA and LA-treated animals, respectively; however, no change was observed with GLA treatment alone. Interestingly, both GLA-LA and LA treatments corrected a diabetes-related decrease in the gastrocnemius muscle low-molecular-weight reduced thiols content. These data demonstrate insulin-sensitizing properties of the GLA-LA conjugate by distinct mechanisms attributable to each of its components, which are associated with antioxidant effects.
PMID: 11233149 [PubMed - indexed for MEDLINE]
Seems like a GLA-ALA conjugate is superior to ALA
by quite a margin.
Supplement companies seem to have largely
ignored this fact.
Fonz
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