Leptin, its implication in physical exercise and training: a short review (original) (raw)
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Plasma leptin and exercise: recent findings
Sports medicine, 2001
stimulates lipid metabolism, and increases energy expenditure. These effects implicate leptin as a major regulator of energy homeostasis, which may serve to limit excess energy storage. As plasma leptin concentrations are tightly coupled with fat mass in humans, decreases in adipose mass with weight loss coincide with decreased concentrations of circulating leptin. However, due to many confounding factors, the effects of exercise on circulating leptin are less clear. The data from investigations examining single exercise bouts suggest that serum leptin concentrations are unaltered by short duration (41 minutes or less), non-exhaustive exercise, but may be affected by short duration, exhaustive exercise. More convincingly, studies investigating long duration exercise bouts indicate that serum leptin concentrations are reduced with exercise durations ranging from one to multiple hours. These findings raise speculation that exercise-associated reductions in leptin may be due to alterations in nutrient availability or nutrient flux at the level of the adipocytes, the primary site of leptin production and secretion. Thus, one purpose of this review is to discuss the effects of exercise on circulating leptin concentrations with special emphasis on studies that have examined single exercise bouts that are associated with high levels of energy expenditure and energy deficit. In addition, a 'nutrient sensing pathway' (the hexosamine biosynthetic pathway), which regulates leptin gene expression, will be discussed as a possible mechanism by which exercise-induced energy deficit may modulate serum leptin concentrations.
Sports Medicine, 2001
stimulates lipid metabolism, and increases energy expenditure. These effects implicate leptin as a major regulator of energy homeostasis, which may serve to limit excess energy storage. As plasma leptin concentrations are tightly coupled with fat mass in humans, decreases in adipose mass with weight loss coincide with decreased concentrations of circulating leptin. However, due to many confounding factors, the effects of exercise on circulating leptin are less clear. The data from investigations examining single exercise bouts suggest that serum leptin concentrations are unaltered by short duration (41 minutes or less), non-exhaustive exercise, but may be affected by short duration, exhaustive exercise. More convincingly, studies investigating long duration exercise bouts indicate that serum leptin concentrations are reduced with exercise durations ranging from one to multiple hours. These findings raise speculation that exercise-associated reductions in leptin may be due to alterations in nutrient availability or nutrient flux at the level of the adipocytes, the primary site of leptin production and secretion. Thus, one purpose of this review is to discuss the effects of exercise on circulating leptin concentrations with special emphasis on studies that have examined single exercise bouts that are associated with high levels of energy expenditure and energy deficit. In addition, a 'nutrient sensing pathway' (the hexosamine biosynthetic pathway), which regulates leptin gene expression, will be discussed as a possible mechanism by which exercise-induced energy deficit may modulate serum leptin concentrations.
Hormone and Metabolic Research, 2014
cise in relation to energy expenditure [11]. In normal as well as in obese subjects, a period of prolonged physical training also promotes a decrease in leptin [12, 13]. Regular exercise is an important strategy in the management of obesity, together with hypocaloric diet and appropriate lifestyle. The aim of this study was to elucidate in obesity the behaviour of leptin after a comparable type of training at work loads of different intensity, that is: 1) after exclusively aerobic work, and 2) after aerobic work plus a bout of anaerobic work. On the basis of previous observations on GH and nonesterified fatty acids (NEFAs) [14, 15], we might presume different behaviours of leptin with regard to differences in quantity of physical training.
Leptin Production during Moderate-Intensity Aerobic Exercise 1
The Journal of Clinical Endocrinology & Metabolism, 1997
Leptin, the protein product of the ob gene, may be involved in the regulation of energy balance. Although a clear relationship between energy intake and plasma leptin concentrations has been demonstrated in humans, little is known about the effect of exercise on leptin metabolism. In the present study, we evaluated abdominal adipose tissue leptin production in vivo by arteriovenous balance at rest and during 60 min of moderate-intensity cycle ergometer exercise (50% of maximal heart rate) in five sedentary male subjects (mean age 38.4 Ϯ 1.7 yr, body mass index (28.4 Ϯ 4.2 kg/m 2 ). Blood samples were taken simultaneously from an abdominal vein, draining sc adipose tissue, and a radial artery, at rest and every 10 min during exercise. Adipose tissue blood flow was determined by the xenon washout technique. Plasma leptin concentrations did not change throughout exercise and were the same as the values obtained during resting conditions. Average net adipose tissue leptin production rates during exercise (3.07 Ϯ 0.89 ng/100 g Ϫ1 ⅐ min Ϫ1 ) also were similar to resting values (3.86 Ϯ 0.95 ng/100 g Ϫ1 ⅐min Ϫ1 ). These results demonstrate that plasma leptin concentrations and leptin production do not change during an acute bout of moderate-intensity aerobic exercise. (J . sc abdominal adipose tissue leptin production rates (mean ϩ SE) at rest and during moderate-intensity cycle ergometer exercise.
Neuro endocrinology letters, 2004
Recent studies have concluded that an energy expenditure by an acute exercise session has no immediate effect on leptin levels while some showed a decline in leptin levels. The purpose of this study was to investigate any possible effects of training status of the subjects on acute exercise-leptin relationship in obese patients. Fourteen obese sedentary females were enrolled to the study and effects of acute incremental exercise on serum leptin levels were determined at rest and at maximal exercise performance. Then, they participated to a 12-weeks endurance aerobic training programme performed in the laboratory on a computer controlled cycle ergometer and their leptin levels were re-evaluated and the leptin-acute exercise relationships obtained under different training levels in the same group of subjects were compared. The body compositions were determined by bioelectrical impedance. Pre and post training blood samples were taken at rest and at the maximal exercise performance. Se...
Effect of short-term exercise training on leptin and insulin action
Metabolism, 2000
The purpose of the study was to determine the effect of short-term exercise training (7 consecutive days for 60 min/d at 75% maximal oxygen consumption [V O 2 max]), which did not change body mass on fasting plasma leptin concentration and insulin action. Young, lean subjects (n ؍ 16; age, 21.9 ؎ 0.6 years; body fat, 17.5% ؎ 1.5%) and older subjects with relatively more adipose tissue (n ؍ 14; age, 58.6 ؎ 1.4 years; body fat, 28.3% ؎ 1.3%) were studied (mean ؎ SE). Fasting plasma leptin was significantly (P F .05) related to adiposity (fat mass, r ؍ .58; % body fat, r ؍ .76) in this population. Body mass did not change (P F .05) in any of the groups with training (71.8 ؎ 2.5 v 71.9 ؎ 2.5 kg). The insulin sensitivity index (S I determined from an intravenous glucose tolerance test (IVGTT) improved significantly (P F .05) in both the young group (4.8 ؎ 0.6 v 6.9 ؎ 0.8 ؋ 10 ؊4 / min (U/mL) and the older group (3.2 ؎ 0.6 v 5.9 ؎ 1.0 ؋ 10 ؊4 /min (U/mL)). Fasting leptin did not change with training in either group (10.4 ؎ 1.6 v 9.2 ؎ 1.0 ng/mL). These findings suggest that exercise does not independently affect the fasting plasma leptin concentration and the improvement in insulin action with exercise is not associated with an alteration in fasting leptin in healthy sedentary lean and relatively lean subjects.
Leptin response to acute prolonged exercise after training in rowers
European Journal of Applied Physiology, 2004
The aim of this study was to determine if there is a training effect on leptin levels at rest or after prolonged exercise during an 8-month training season of rowers. Eleven trained rowers were evaluated at three sessions (control, early and late) during the season. At the early and late sessions, leptin and insulin concentrations were measured before and after 90 min of rowing exercise (70-75% maximal oxygen consumption, _ V O 2 max), 120 min and 24 h afterwards. Anthropometrics data were collected at each session. Energy balance was determined on the days of exercise sessions. Resting leptin levels were not modified over the season and were in correlation with weight and body fat (P<0.05). At exercise sessions, a delayed reducing effect of acute exercise on leptin levels appeared (P<0.01 compared to pre-exercise). After 24 h of recovery, leptin levels remained lower at early (P<0.001) but not at late sessions, and a training effect appeared between early and late sessions (P<0.001). Leptin levels were correlated with energy balance at early and late sessions (P<0.05). At the two training sessions, insulin levels were decreased immediately post-exercise and at 120 min of recovery compared to pre-exercise (P<0.01 and P<0.001 respectively for the two sessions). A training effect on insulin levels appeared at 24 h of recovery (P<0.05 between early and late sessions). We concluded that rowing training over a season did not alter resting leptin levels but it attenuated the exercise-induced reduction in leptin. This could be attributed to an alteration in energy balance, although an influence of training on insulin may also be involved in the leptin response to acute exercise.
We examined the leptin response and related hormones during and after two sub-maximal exercise protocols in trained and untrained subjects. During this study, plasma concentrations of leptin [Lep], insulin [I], cortisol [C], growth hormone [GH], glucose [G] and lactate [La] were measured. 7 elite volleyball trained players (TR) and 7 untrained (UTR) subjects (percent body fat: 13.2 ± 1.8 versus 15.7 ± 1.0, p < 0.01, respectively) were examined after short and prolonged sub-maximal cycling exercise protocols (SP and PP). Venous blood samples were collected before each protocol, during, at the end, and after 2 and 24 h of recovery. SP and PP energy expenditures ranged from 470 ± 60 to 740 ± 90 kcal for TR and from 450 ± 60 to 710 ± 90 kcal for UTR, respectively.
Effect of energy expenditure and training status on leptin response to sub-maximal cycling
We examined the leptin response and related hormones during and after two sub-maximal exercise protocols in trained and untrained subjects. During this study, plasma concentrations of leptin [Lep], insulin [I], cortisol [C], growth hormone [GH], glucose [G] and lactate [La] were measured. 7 elite volleyball trained players (TR) and 7 untrained (UTR) subjects (percent body fat: 13.2 ± 1.8 versus 15.7 ± 1.0, p < 0.01, respectively) were examined after short and prolonged sub-maximal cycling exercise protocols (SP and PP). Venous blood samples were collected before each protocol, during, at the end, and after 2 and 24 h of recovery. SP and PP energy expenditures ranged from 470 ± 60 to 740 ± 90 kcal for TR and from 450 ± 60 to 710 ± 90 kcal for UTR, respectively.