Enzymatic microdetermination of serum free fatty acids

Shimizu, Sakayu; Inoue, Keiko; Tani, Yoshiki; Yamada, Hideaki

doi:10.1016/0003-2697(79)90151-9

Cited by 212 publications

(72 citation statements)

References 11 publications

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“…Blood lactate was measured with a fluorimetric technique that had an overall coefficient of variation (CV) of 5.2 Ϯ 3.8% (21). The total FFA concentration was determined with a microenzymatic technique (CV 6.9 Ϯ 2.3%) (22). Plasma insulin and C-peptide were measured by conventional radioimmunoassay (6 Ϯ 4% and 5.3 Ϯ 3.2%, respect i v e l y ) ( 2 3 ) .…”

Section: Methodsmentioning

confidence: 99%

Acute Alcohol Consumption Improves Insulin Action Without Affecting Insulin Secretion in Type 2 Diabetic Subjects

et al. 2004

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OBJECTIVE -Long-term exposure to alcohol is associated with an improvement in insulin sensitivity. At this time, however, there is no definitive proof that alcohol per se has an effect on the insulin sensitivity index (S i ) in type 2 diabetes patients. The aim of the present study was to assess the role of acute moderate alcohol intake on insulin sensitivity and insulin secretion in comparable subjects with and without type 2 diabetes.RESEARCH DESIGN AND METHODS -Frequently sampled intravenous glucose tolerance tests (FSIGTs) were performed twice on eight healthy and eight type 2 diabetic volunteers. Forty grams of alcohol (vodka 40% wt/vol) or tap water were sipped from time Ϫ60 min to the end of the FSIGT.RESULTS -Lactate area under the curve (AUC) was higher in both groups during the alcohol study than in the control study. Free fatty acid (FFA) AUC was higher in type 2 diabetic subjects than in control subjects; alcohol slightly reduced FFA by 17% in control subjects (34 Ϯ 4 mmol ⅐ min Ϫ1 ⅐ l Ϫ1 ; P ϭ 0.1) but significantly decreased FFA by 23% in type 2 diabetic subjects (54 Ϯ 10; P ϭ 0.007). ␤-Cell response was markedly reduced in type 2 diabetic subjects regardless of the type of study. Alcohol significantly increased S i in both groups.CONCLUSIONS -Acute alcohol consumption improves insulin action without affecting ␤-cell secretion. This effect may be partly due to the inhibitory effect of alcohol on lipolysis. Alcohol intake increases insulin sensitivity and may partly explain both the J-shaped relationship between the prevalence of diabetes and the amount of alcohol consumption and the decreased mortality for myocardial infarction. Diabetes Care 27:1369 -1374, 2004R eports consistently suggest that the intake of a significant amount of alcohol induces a state of insulin resistance, assessed either with oral or intravenous glucose tolerance tests (1-3). However, a large body of epidemiological evidence from cross-sectional studies also suggests long-term exposure to alcohol is associated with an improvement in insulin sensitivity (4 -8). Furthermore, a substantial number of prospective studies indicate that light to moderate chronic alcohol intake improves glucose metabolism and is protective against coronary artery disease in subjects with type 2 diabetes (9 -13). Historically, alcohol use by the diabetic patient has been controversial; however, in light of these premises, moderate alcohol consumption should, at least in part, contribute to improved insulin sensitivity. Indeed, moderate alcohol intake taken with a meal has been shown to have little or no effect on postprandial glycemic excursions, whereas heavy intake yields opposite effects (14 -20). At this time, however, there is no definitive proof that alcohol per se has an effect on insulin sensitivity in patients with type 2 diabetes. Therefore, the aim of the present study was to test the hypothesis that acute alcohol intake might improve insulin sensitivity and secretion in comparable subjects with and without type 2 diabetes. Moreover, we wi...

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Section: Methodsmentioning

confidence: 99%

Acute Alcohol Consumption Improves Insulin Action Without Affecting Insulin Secretion in Type 2 Diabetic Subjects

et al. 2004

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“…Plasma lactate and glucose were analyzed in triplicate by use of an Analox Micro-Stat GM7 analyzer (Analox Instruments, Lunenburg, MA). Plasma free fatty acid (FFA) was determined enzymatically according to the method of Shimizu et al (28). For separation of plasma free tryptophan and albumin-bound tryptophan, the remaining plasma (ϳ1 ml) was transferred to a Centrifree micropartition device (Millipore, Bedford, MA) and centrifuged at 1,500 g at 25°C for 20 min.…”

Section: Methodsmentioning

confidence: 99%

Effects of l-tyrosine and carbohydrate ingestion on endurance exercise performance

Chinevere

Sawyer

Creer

et al. 2002

Journal of Applied Physiology

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To test the effects of tyrosine ingestion with or without carbohydrate supplementation on endurance performance, nine competitive cyclists cycled at 70% peak oxygen uptake for 90 min under four different feeding conditions followed immediately by a time trial. At 30-min intervals, beginning 60 min before exercise, each subject consumed either 5 ml/kg body wt of water sweetened with aspartame [placebo (Pla)], polydextrose (70 g/l) (CHO), L-tyrosine (25 mg/kg body wt) (Tyr), or polydextrose (70 g/l) and L-tyrosine (25 mg/kg body wt) (CHOϩTyr). The experimental trials were given in random order and were carried out by using a counterbalanced double-blind design. No differences were found between treatments for oxygen uptake, heart rate, or rating of perceived exertion at any time during the 90-min ride. Plasma tyrosine rose significantly from 60 min before exercise to test termination (TT) in Tyr (means Ϯ SE) (480 Ϯ 26 mol) and CHOϩTyr (463 Ϯ 34 mol) and was significantly higher in these groups from 30 min before exercise to TT vs. CHO (90 Ϯ 3 mol) and Pla (111 Ϯ 7 mol) (P Ͻ 0.05). Plasma free tryptophan was higher after 90 min of exercise, 15 min into the endurance time trial, and at TT in Tyr (10.1 Ϯ 0.9, 10.4 Ϯ 0.8, and 12.0 Ϯ 0.9 mol, respectively) and Pla (9.7 Ϯ 0.5, 10.0 Ϯ 0.3, and 11.7 Ϯ 0.5 mol, respectively) vs. CHO (7.8 Ϯ 0.5, 8.6 Ϯ 0.5, and 9.3 Ϯ 0.6 mol, respectively) and CHOϩTyr (7.8 Ϯ 0.5, 8.5 Ϯ 0.5, 9.4 Ϯ 0.5 mol, respectively) (P Ͻ 0.05). The plasma tyrosine-to-free tryptophan ratio was significantly higher in Tyr and CHOϩTyr vs. CHO and Pla from 30 min before exercise to TT (P Ͻ 0.05). CHO (27.1 Ϯ 0.9 min) and CHOϩTyr (26.1 Ϯ 1.1 min) treatments resulted in a reduced time to complete the endurance time trial compared with Pla (34.4 Ϯ 2.9 min) and Tyr (32.6 Ϯ 3.0 min) (P Ͻ 0.05). These findings demonstrate that tyrosine ingestion did not enhance performance during a cycling time trial after 90 min of steady-state exercise. central fatigue; cycling; perceived exertion RECENTLY, IT HAS BEEN HYPOTHESIZED that, during prolonged exercise, an increased concentration of brain serotonin may be an important factor in the onset of central nervous system fatigue (2-4, 8, 10, 27) and a high serotonin-to-dopamine ratio results in fatigue (17). Brain serotonin synthesis depends on the availability of free tryptophan, its amino acid precursor, and the activity of the rate-limiting enzyme, tryptophan hydroxylase (7, 10). Similarly, tyrosine is the amino acid precursor to dopamine (32). These amino acid precursors compete for transport across the bloodbrain barrier via the same carrier mechanism (17).We speculated that, if tyrosine were elevated in the blood by ingestion during exercise and competed for transport across the blood brain barrier with tryptophan, increased uptake of tyrosine and a decreased uptake of tryptophan could result in a lower brain serotonin/dopamine ratio and improved endurance.Limited research has been done on the effects of tyrosine ingestion on exercise endurance. Struder et al. (30) rep...

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“…The LDL-cholesterol concentration was calculated from the total cholesterol, triglycerides, and HDL-cholesterol values using the Friedewald formula [15]. Non-esterified free fatty acid concentrations were analysed by an enzymatic colorimetric assay (Boehringer Mannheim, Mannheim, Germany) [16]. To reduce interassay variation, plasma for biochemical determinations were stored at -80°C and analysed in duplicate at the end of the study.…”

Section: Methodsmentioning

confidence: 99%

The SstI polymorphism of the apo C-III gene is associated with insulin sensitivity in young men

Pérez‐Jiménez

Gomez

et al. 2002

Diabetologia

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Aims/hypothesis. Insulin resistance is considered to be a risk factor for diabetes and coronary heart disease and is determined by the interaction between genetic and environmental factors. The SstI polymorphism in the apolipoprotein C-III gene has been related to the presence of different features of the insulin resistance syndrome. We investigate if this mutation influences the peripheral effect of insulin in healthy young subjects (30 men and 29 women) eating a westernised diet. Methods. We investigated peripheral insulin sensitivity with the insulin suppression test after a 28-day westernised high-saturated fat diet (38% total fat and 18% saturated fat with 115 mg of cholesterol per 1000 Ju). Results. Steady state plasma glucose values were lower in S1-S1 compared with S1-S2 men (p=0.018 by ANOVA), but not in women (p=0.723). Conclusion/interpretation. There was no difference between carriers and non-carriers of the S2 allele in relation to incidence and sensitivity; although on subgroup analysis there was an effect in men but not in women. [Diabetologia (2002[Diabetologia ( ) 45:1196[Diabetologia ( -1200 Keywords High-saturated fat diet, insulin sensitivity, glucose metabolism, non-esterified fatty acids.

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Enzymatic microdetermination of serum free fatty acids

Cited by 212 publications

References 11 publications

Acute Alcohol Consumption Improves Insulin Action Without Affecting Insulin Secretion in Type 2 Diabetic Subjects

Acute Alcohol Consumption Improves Insulin Action Without Affecting Insulin Secretion in Type 2 Diabetic Subjects

Effects of l-tyrosine and carbohydrate ingestion on endurance exercise performance

The SstI polymorphism of the apo C-III gene is associated with insulin sensitivity in young men

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