Lipolytic suppression following carbohydrate ingestion limits fat oxidation during exercise

1997 ◽  
Vol 273 (4) ◽  
pp. E768-E775 ◽  
Author(s):  
Jeffrey F. Horowitz ◽  
Ricardo Mora-Rodriguez ◽  
Lauri O. Byerley ◽  
Edward F. Coyle
Keyword(s):  
Oxygen Consumption ◽  
Plasma Insulin ◽  
Fat Oxidation ◽  
Insulin Concentration ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Plasma Insulin Concentration ◽  
Carbohydrate Ingestion ◽  
The Mean

This study determined if the suppression of lipolysis after preexercise carbohydrate ingestion reduces fat oxidation during exercise. Six healthy, active men cycled 60 min at 44 ± 2% peak oxygen consumption, exactly 1 h after ingesting 0.8 g/kg of glucose (Glc) or fructose (Fru) or after an overnight fast (Fast). The mean plasma insulin concentration during the 50 min before exercise was different among Fast, Fru, and Glc (8 ± 1, 17 ± 1, and 38 ± 5 μU/ml, respectively; P< 0.05). After 25 min of exercise, whole body lipolysis was 6.9 ± 0.2, 4.3 ± 0.3, and 3.2 ± 0.5 μmol ⋅ kg−1 ⋅ min−1and fat oxidation was 6.1 ± 0.2, 4.2 ± 0.5, and 3.1 ± 0.3 μmol ⋅ kg−1 ⋅ min−1during Fast, Fru, and Glc, respectively (all P < 0.05). During Fast, fat oxidation was less than lipolysis ( P < 0.05), whereas fat oxidation approximately equaled lipolysis during Fru and Glc. In an additional trial, the same subjects ingested glucose (0.8 g/kg) 1 h before exercise and lipolysis was simultaneously increased by infusing Intralipid and heparin throughout the resting and exercise periods (Glc+Lipid). This elevation of lipolysis during Glc+Lipid increased fat oxidation 30% above Glc (4.0 ± 0.4 vs. 3.1 ± 0.3 μmol ⋅ kg−1 ⋅ min−1; P < 0.05), confirming that lipolysis limited fat oxidation. In summary, small elevations in plasma insulin before exercise suppressed lipolysis during exercise to the point at which it equaled and appeared to limit fat oxidation.

Substrate metabolism when subjects are fed carbohydrate during exercise

1999 ◽  
Vol 276 (5) ◽  
pp. E828-E835 ◽  
Author(s):  
Jeffrey F. Horowitz ◽  
Ricardo Mora-Rodriguez ◽  
Lauri O. Byerley ◽  
Edward F. Coyle
Keyword(s):  
Plasma Insulin ◽  
Fat Oxidation ◽  
Insulin Concentration ◽  
Peak Oxygen Consumption ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Plasma Insulin Concentration ◽  
Carbohydrate Ingestion ◽  
Low Intensity ◽  
Low Intensity Exercise

This study determined the effect of carbohydrate ingestion during exercise on the lipolytic rate, glucose disappearance from plasma (Rd Glc), and fat oxidation. Six moderately trained men cycled for 2 h on four separate occasions. During two trials, they were fed a high-glycemic carbohydrate meal during exercise at 30 min (0.8 g/kg), 60 min (0.4 g/kg), and 90 min (0.4 g/kg); once during low-intensity exercise [25% peak oxygen consumption (V˙o 2 peak)] and once during moderate-intensity exercise (68%V˙o 2 peak). During two additional trials, the subjects remained fasted (12–14 h) throughout exercise at each intensity. After 55 min of low-intensity exercise in fed subjects, hyperglycemia (30% increase) and a threefold elevation in plasma insulin concentration ( P < 0.05) were associated with a 22% suppression of lipolysis compared with when subjects were fasted (5.2 ± 0.5 vs. 6.7 ± 1.2 μmol ⋅ kg−1 ⋅ min−1, P < 0.05), but fat oxidation was not different from fasted levels at this time. Fat oxidation when subjects were fed carbohydrate was not reduced below fasting levels until 80–90 min of exercise, and lipolysis was in excess of fat oxidation at this time. The reduction in fat oxidation corresponded in time with the increase in Rd Glc. During moderate-intensity exercise, the very small elevation in plasma insulin concentration (∼3 μU/ml; P < 0.05) during the second hour of exercise when subjects were fed vs. when they were fasted slightly attenuated lipolysis ( P < 0.05) but did not increase Rd Glc or suppress fat oxidation. These findings indicate that despite a suppression of lipolysis after carbohydrate ingestion during exercise, the lipolytic rate remained in excess and thus did not limit fat oxidation. Under these conditions, a reduction in fat oxidation was associated in time with an increase in glucose uptake.

EFFECT OF DECAPITATION ON THE DEVELOPMENT OF INSULIN SECRETION IN THE FOETAL RABBIT

1973 ◽  
Vol 57 (1) ◽  
pp. 23-31 ◽  
Author(s):  
P. M. B. JACK ◽  
R. D. G. MILNER
Keyword(s):  
Insulin Secretion ◽  
Plasma Insulin ◽  
Insulin Concentration ◽  
Β Cell ◽  
Plasma Insulin Concentration ◽  
Intrauterine Development ◽  
Foetal Head ◽  
Significant Difference ◽  
The Mean ◽  
Control Litter

SUMMARY One rabbit foetus in a litter was decapitated on day 24 of gestation. On day 29 the litter was killed and blood was collected from all foetuses for the measurement of plasma insulin concentration. The pancreas of the decapitated foetus and that of the control litter-mate with the nearest headless body weight were cut into pieces and incubated in a physiological buffer containing 0·6 or 3·0 mg glucose/ml. The pancreas of the decapitated foetus secreted significantly more insulin than that of the control foetus in either concentration of glucose in the medium. Higher insulin secretion from the decapitated foetus persisted for 4·5 h of incubation and was demonstrable in both the first 5 and subsequent 25 min of incubation when the pancreas was initially transferred to incubation medium containing 3·0 mg glucose/ml. The mean plasma insulin concentration of the foetuses decapitated on day 24 was higher on day 29 than that of the control foetuses but there was no significant difference between the concentration of insulin in the pancreas of the two groups of animals. The results indicate that removal of the foetal head influences the intrauterine development of the rabbit β-cell.

scholarly journals Maximal Fat Oxidation: Comparison between Treadmill, Elliptical and Rowing Exercises

2021 ◽  
pp. 170-178
Author(s):  
Michelle Filipovic ◽  
Stephanie Munten ◽  
Karl-Heinz Herzig ◽  
Dominique D. Gagnon
Keyword(s):  
Oxygen Consumption ◽  
Venous Blood ◽  
Maximal Oxygen Consumption ◽  
Blood Gases ◽  
Fat Oxidation ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Mixed Venous Blood ◽  
Exercise Modality ◽  
Maximal Fat Oxidation

Fat oxidation during exercise is associated with cardio-metabolic benefits, but the extent of which whole-body exercise modality elicits the greatest fat oxidation remains unclear. We investigated the effects of treadmill, elliptical and rowing exercise on fat oxidation in healthy individuals. Nine healthy males participated in three, peak oxygen consumption tests, on a treadmill, elliptical and rowing ergometer. Indirect calorimetry was used to assess maximal oxygen consumption (V̇O2peak), maximal fat oxidation (MFO) rates, and the exercise intensity MFO occurred (Fatmax). Mixed venous blood was collected to assess lactate and blood gases concentrations. While V̇O2peak was similar between exercise modalities, MFO rates were higher on the treadmill (mean ± SD; 0.61 ± 0.06 g·min-1) compared to both the elliptical (0.41 ± 0.08 g·min-1, p = 0.022) and the rower (0.40 ± 0.08 g·min-1, p = 0.017). Fatmax values were also significantly higher on the treadmill (56.0 ± 6.2 %V̇O2peak) compared to both the elliptical (36.8 ± 5.4 %V̇O2peak, p = 0.049) and rower (31.6 ± 5.0 %V̇O2peak, p = 0.021). Post-exercise blood lactate concentrations were also significantly lower following treadmill exercise (p = 0.021). Exercising on a treadmill maximizes fat oxidation to a greater extent than elliptical and rowing exercises, and remains an important exercise modality to improve fat oxidation, and consequently, cardio-metabolic health.

THE EFFECT OF A HIGH-FAT DIET ON GLUCOSE, INSULIN SENSITIVITY AND PLASMA INSULIN IN RATS

1968 ◽  
Vol 42 (4) ◽  
pp. 489-494 ◽  
Author(s):  
E. BLÁZQUEZ ◽  
C. LOPEZ QUIJADA
Keyword(s):  
Plasma Glucose ◽  
High Fat Diet ◽  
Plasma Insulin ◽  
Diet Group ◽  
Insulin Concentration ◽  
Control Group ◽  
High Fat ◽  
Plasma Insulin Concentration ◽  
The Mean

SUMMARY The influence of the diet on the levels of insulin was studied in rats on a high-fat diet. Plasma and glucose insulin concentrations of a control group and of rats on a high-fat diet were compared, and so was the insulin concentration in the pancreas of the two groups. The mean plasma insulin concentration in the control group was 40 μ-u./ml. and that of insulin extracted from the pancreas was 2·5 μg./100 mg. tissue; plasma glucose was 156 mg./100 ml. The animals fed on a high-fat diet showed diabetic features. The mean plasma insulin level was 9 μ-u./ml., and plasma glucose increased to 210 mg./100 ml. The insulin concentration in the pancreas was not significantly different from that in the controls. In vitro the epididymal fat and the diaphragm of the high-fat-diet group were less sensitive to insulin than the same tissues in the control group.

A single 1-h bout of evening exercise increases basal FFA flux without affecting VLDL-triglyceride and VLDL-apolipoprotein B-100 kinetics in untrained lean men

2007 ◽  
Vol 292 (6) ◽  
pp. E1568-E1574 ◽  
Author(s):  
Faidon Magkos ◽  
Bruce W. Patterson ◽  
B. Selma Mohammed ◽  
Bettina Mittendorfer
Keyword(s):  
Oxygen Consumption ◽  
Apolipoprotein B ◽  
Late Phase ◽  
Fat Oxidation ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Moderate Intensity ◽  
Oxidation Rates ◽  
Tracer Techniques ◽  
Vldl Triglyceride

Our group (Magkos F, Wright DC, Patterson BW, Mohammed BS, Mittendorfer B, Am J Physiol Endocrinol Metab 290: E355–E362, 2006) has recently demonstrated that a single, prolonged bout of moderate-intensity cycling (2 h at 60% of peak oxygen consumption) in the evening increases basal whole-body free fatty acid (FFA) flux and fat oxidation, decreases hepatic VLDL-apolipoprotein B-100 (apoB-100) secretion, and enhances removal efficiency of VLDL-triglyceride (TG) from the circulation the following day in untrained, healthy, lean men. In the present study, we investigated the effect of a single, shorter-duration bout of the same exercise (1 h cycling at 60% of peak oxygen consumption) on basal FFA, VLDL-TG, and VLDL-apoB-100 kinetics in seven untrained, healthy, lean men by using stable isotope-labeled tracer techniques. Basal FFA rate of appearance in plasma and plasma FFA concentration were ∼55% greater ( P < 0.05) the morning after exercise than rest, whereas resting metabolic rate and whole-body substrate oxidation rates were not different after rest and exercise. Exercise had no effect on plasma VLDL-TG and VLDL-apoB-100 concentrations, hepatic VLDL-TG and VLDL-apoB-100 secretion rates, and VLDL-TG and VLDL-apoB-100 plasma clearance rates (all P > 0.05). We conclude that in untrained, healthy, lean men 1) the exercise-induced changes in basal whole-body fat oxidation, VLDL-TG, and VLDL-apoB-100 metabolism during the late phase of recovery from exercise are related to the duration of the exercise bout; 2) single sessions of typical recreational activities appear to have little effect on basal, fasting plasma TG homeostasis; and 3) there is a dissociation between systemic FFA availability and VLDL-TG and VLDL-apoB-100 secretion by the liver.

The effect of previous body condition on appetite and associated insulin profiles in sheep

1997 ◽  
Vol 64 (2) ◽  
pp. 247-252 ◽  
Author(s):  
A. M. Sibbald ◽  
S. M. Rhind
Keyword(s):  
Food Intake ◽  
Body Condition ◽  
Dry Matter ◽  
Plasma Insulin ◽  
Insulin Concentration ◽  
Feedback Signal ◽  
Plasma Insulin Concentration ◽  
Condition Score ◽  
The Mean ◽  
Ad Libitum

AbstractThe effect of previous level of body condition on appetite was studied in 47 housed Scottish Blackface ewes, which had been either thin (L: mean condition score 2·15, s.e. 0·030; no. = 24) or fat (H: mean condition score 3·15, s.e. 0·056; no. = 23) 8 weeks before the start of the experiment. The mean daily voluntary food intake (VFI) of a dried grass pellet diet was higher for the L than for the H ewes (2176 v. 1727 g dry matter per day; P < 0·001) during the first 6 weeks of the experiment (period 1). Over this time, live weights increased from 60·5 or 69·9 (s.e.d. 1·68) to 68·4 or 75·6 (s.e.d. 1·94) and condition scores increased from 2·84 or 3·16 (s.e.d. 0·057) to 3·13 or 3·38 (s.e.d. 0·071) for the L and H ewes respectively.At the end of the 6-week period, plasma insulin concentrations were measured in 10 ewes from each treatment (mean condition scores 3·15 (L) and 3·27 (H) (s.e.d. 0·091)) when fed both ad libitum and at a fixed level of 1200 g/day for consecutive 11-day periods (period 2). Mean VFI was higher for the L than for the H ewes (2191 v. 1661 g dry matter per day; P < 0·05) over the period of ad libitum feeding. There was no effect of feeding level (ad libitum v. 1200 g/day) on mean plasma insulin concentrations, but the mean basal plasma insulin concentration was higher in the H than in the L ewes (43·0 v. 29·0 mil per 1; P < 0·05). Fifteen minutes after the ingestion of a single 400 g meal, the plasma insulin concentration in the H ewes was higher than the mean prefeeding value (63·3 v. 41·7 mil per I; P<0·05) but there was no corresponding increase in the L ewes. The plasma insulin concentration 15 min after the intravenous administration of a single dose of 0·25 U per kg live weight of insulin ivas higher in the H than in the L ewes (1723 v. 1031 mil per 1; P < 0·01) but there were no differences between treatments in plasma glucose concentrations following insulin administration.It was concluded that previous body condition can affect contemporary VFI and this effect may be mediated by plasma insulin concentrations providing a long-term feedback signal to the brain. Keywords: body condition, food intake, insulin, sheep.

Stimulation of muscle glucose disposal by insulin in humans is a function of the preexisting plasma insulin level

1995 ◽  
Vol 268 (5) ◽  
pp. E1031-E1038
Author(s):  
C. Vogt ◽  
A. S. Petrides
Keyword(s):  
Plasma Insulin ◽  
Glycogen Synthase ◽  
Insulin Concentration ◽  
Whole Body ◽  
Glucose Disposal ◽  
Glucose Turnover ◽  
Somatostatin Analogue ◽  
Plasma Insulin Concentration ◽  
Before And After ◽  
Glycogen Synthase Activity

To examine whether tissue sensitivity to insulin is dependent upon the prevailing plasma insulin concentration, the ability of acute hyperinsulinemia to stimulate glucose disposal was investigated in six normal subjects before and after prolonged reduction of the plasma insulin concentration. Glucose turnover ([6,6-2H2]glucose), whole body glucose oxidation and nonoxidative glucose disposal (indirect calorimetry), and glycogen synthase activity in muscle were determined in the postabsorptive and in the insulin-stimulated states (euglycemic hyperinsulinemic clamp: 3 mU.kg-1.min-1) before and after a 4-day subcutaneous infusion of the somatostatin analogue octreotide (200 micrograms/24 h). Constant octreotide infusion 1) decreased postabsorptive and meal-stimulated plasma insulin levels by approximately 30-40% but did not significantly alter overall glucose tolerance, free fatty acid, growth hormone, and glucagon levels and 2) was associated with significant increases in insulin-mediated whole body glucose disposal (pre-drug: 10.29 +/- 0.49 vs. postdrug: 11.42 +/- 0.72 mg.kg-1.min-1, P < 0.04), nonoxidative glucose disposal (6.82 +/- 0.57 vs. 7.68 +/- 0.62, P < 0.03), and fractional glycogen synthase activity (0.14 +/- 0.03 vs. 0.20 +/- 0.04 mU/mg protein, P < 0.02). In contrast, infusion of saline instead of octreotide for 4 days to control subjects did not alter any of the metabolic parameters. We conclude that lowering the plasma insulin concentration over a prolonged period of time increases insulin sensitivity. The effects of insulin to stimulate whole body glucose utilization, nonoxidative glucose disposal, and glycogen synthase activity in muscle are therefore functions of the preexisting plasma insulin concentration.

Comparison of thermogenic effect of fructose and glucose in normal humans

1986 ◽  
Vol 250 (6) ◽  
pp. E718-E724 ◽  
Author(s):  
L. Tappy ◽  
J. P. Randin ◽  
J. P. Felber ◽  
R. Chiolero ◽  
D. C. Simonson ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Lipid Oxidation ◽  
Plasma Insulin ◽  
Carbohydrate Oxidation ◽  
Insulin Concentration ◽  
Adrenergic Blockade ◽  
Plasma Insulin Concentration ◽  
Carbohydrate Ingestion ◽  
Glucose Ingestion ◽  
Adrenergic Nervous System

After nutrient ingestion there is an increase in energy expenditure that has been referred to as dietary-induced thermogenesis. In the present study we have employed indirect calorimetry to compare the increment in energy expenditure after the ingestion of 75 g of glucose or fructose in 17 healthy volunteers. During the 4 h after glucose ingestion the plasma insulin concentration increased by 33 +/- 4 microU/ml and this was associated with a significant increase in carbohydrate oxidation and decrement in lipid oxidation. Energy expenditure increased by 0.08 +/- 0.01 kcal/min. When fructose was ingested, the plasma insulin concentration increased by only 8 +/- 2 microU/ml vs. glucose. Nonetheless, the increments in carbohydrate oxidation and decrement in lipid oxidation were significantly greater than with glucose. The increment in energy expenditure was also greater with fructose. When the mean increment in plasma insulin concentration after fructose was reproduced using the insulin clamp technique, the increase in carbohydrate oxidation and decrement in lipid oxidation were markedly reduced compared with the fructose-ingestion study; energy expenditure failed to increase above basal levels. To examine the role of the adrenergic nervous system in fructose-induced thermogenesis, fructose ingestion was also performed during beta-adrenergic blockade with propranolol. The increase in energy expenditure during fructose plus propranolol was lower than with fructose ingestion alone. These results indicate that the stimulation of thermogenesis after carbohydrate ingestion is related to an augmentation of cellular metabolism and is not dependent on an increase in the plasma insulin concentration per se.(ABSTRACT TRUNCATED AT 250 WORDS)

RADIOIMMUNOASSAY OF INSULIN IN PLASMA AND URINE IN OBESE SUBJECTS AND IN DIABETIC PATIENTS

1969 ◽  
Vol 60 (4) ◽  
pp. 719-736 ◽  
Author(s):  
Kai R. Jorgensen
Keyword(s):  
Glucose Tolerance ◽  
Urinary Excretion ◽  
Plasma Insulin ◽  
Normal Subjects ◽  
Insulin Concentration ◽  
Plasma Insulin Concentration ◽  
Glucose Tolerance Tests ◽  
Obese Subjects ◽  
Fasting Plasma Insulin ◽  
The Mean

ABSTRACT By the use of the double antibody method the immunologically demonstrable insulin, both in the plasma and urine of obese subjects without clinically manifest diabetes and in diabetics who had not been treated with insulin has been determined. In obese subjects without clinically manifest diabetes, hyperinsulinism was found both in the fasting state and during the glucose tolerance tests. In these subjects the 24-hour urinary excretion of insulin was significantly higher than in that of normal subjects. In obese diabetics the mean fasting plasma insulin concentration was found to be significantly higher than in normal subjects, but during oral glucose tolerance tests, despite marked hyperglycaemia, the increase in the mean plasma insulin concentration was only of the same order as in that of normal subjects and had a maximum that was reached later. The 24-hour urinary excretion of insulin in obese diabetics was of the same order as in that of normal subjects. In non-obese diabetics the mean fasting plasma insulin concentration was lower than in normal subjects and lowest in the poorest regulated diabetics with high fasting blood sugar and ketonuria. During glucose tolerance tests it was not possible to demonstrate any increase in the plasma insulin concentration in the non-obese diabetics with ketonuria, while in non-obese diabetics without ketonuria a slight increase in the plasma insulin concentration was found during glucose tolerance tests. The 24-hour urinary excretion of insulin was reduced in relation to the excretion in normal subjects. Thus, the investigations have shown that hyperinsulinism should be regarded as a characteristic of obesity per se, while the clinically manifest diabetes is always connected with hypoinsulinism in relation to body weight.

scholarly journals 146 Nutritional Advances in Fetal and neonatal development: effect of fatty acid supplementation

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 121-122
Author(s):  
Alejandro E Relling
Keyword(s):  
Small Intestine ◽  
Fatty Acid ◽  
Plasma Insulin ◽  
Linear Increase ◽  
Late Gestation ◽  
Insulin Concentration ◽  
Plasma Insulin Concentration ◽  
Pufa Supplementation ◽  
Epa And Dha ◽  
Offspring Growth

Abstract Data from a series of experiments demonstrates that maternal supply of polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), during late gestation affects offspring growth. The increase in growth is independent on the fatty acid supplemented during the growing or finishing phase of the offspring; but it is sex dependent. Dam PUFA supplementation increases wether growth. Supplementation with EPA and DHA to pregnant ewes and to their offspring after weaning showed a treatment interaction in mRNA concentration of hypothalamic neuropeptides associated with dry matter intake (DMI) regulation. A dose increased in EPA and DHA in pregnant ewe diets shows a linear increase in growth, but a quadratic change in DMI or feed efficiency; growth was associated with a linear increase in plasma glucose concentration and a linear decrease in plasma ghrelin concentration. In lambs born from ewes supplemented with different sources of FA during a glucose tolerance test; males’ plasma insulin concentration increased as FA unsaturation degree increased in the dam diet, the opposite happened with females’ plasma insulin concentration. Recent data from our lab showed that the supplementation with EPA and DHA during the last third of gestation to pregnant ewes increased liver and small intestine global DNA methylation and small intestine transporters for amino acids in the fetus. Despite EPA and DHA during late gestation increase growth in the offspring; when EPA and DHA were supplemented in early gestation, offspring growth was lesser that lambs born from ewes supplemented a saturated and monounsaturated lipid. The reason for the difference in results it is not clear. However, more studies focusing in some aspect of the biology will help to understand what specific fatty acid needs to be supplemented at different stages of gestation to improve offspring growth.

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