Ghrelin is an orexigenic hormone secreted from endocrine cells in the stomach and other tissues. Acylation of ghrelin is essential for appetite regulation. Vigorous exercise induces appetite suppression, but this does not appear to be related to suppressed concentrations of total ghrelin. This study examined the effect of exercise and feeding on plasma acylated ghrelin and appetite. Nine male subjects aged 19-25 yr participated in two, 9-h trials (exercise and control) in a random crossover design. Trials began at 0800 in the morning after an overnight fast. In the exercise trial, subjects ran for 60 min at 72% of maximum oxygen uptake between 0800 and 0900. After this, they rested for 8 h and consumed a test meal at 1100. In the control trial, subjects rested for 9 h and consumed a test meal at 1100. Area under the curve values for plasma acylated ghrelin concentration (assessed from venous blood samples) were lower over the first 3 h and the full 9 h of the exercise trial compared with the control trial: 317+/-135 vs. 510+/-186 pg.ml(-1).3 h and 917+/-342 vs. 1,401+/-521 pg.ml(-1).9 h (means+/-SE) respectively (P<0.05). Area under the curve values for hunger (assessed using a visual scale) were lower over the first 3 h of the exercise trial compared with the control trial (P=0.013). These findings demonstrate that plasma acylated ghrelin concentration and hunger are suppressed during running.

Study design: Retrospective, longitudinal analysis of motor recovery data from individuals with cervical (C4-C7) sensorimotor complete spinal cord injury (SCI) according to the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI).Objectives: To analyze the extent and patterns of spontaneous motor recovery over the first year after traumatic cervical sensorimotor complete SCI. Methods: Datasets from the European multicenter study about SCI (EMSCI) and the Sygen randomized clinical trial were examined for conversion of American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade, change in upper extremity motor score (UEMS) or motor level, as well as relationships between these measures. Results: There were no overall differences between the EMSCI and Sygen datasets in motor recovery patterns. After 1 year, up to 70% of subjects spontaneously recovered at least one motor level, but only 30% recovered two or more motor levels, with lesser values at intermediate time points. AIS grade conversion did not significantly influence motor level changes. At 1 year, the average spontaneous improvement in bilateral UEMS was 10-11 motor points. There was only moderate relationship between a change in UEMS and a change in cervical motor level (r 2 ¼ 0.30, Po0.05). Regardless of initial cervical motor level, most individuals recover a similar number of motor points or motor levels. Conclusion: Careful tracking of cervical motor recovery outcomes may provide the necessary sensitivity and accuracy to reliably detect a subtle, but meaningful treatment effect after sensorimotor complete cervical SCI. The distribution of the UEMS change may be more important functionally than the total UEMS recovered.

Exercise facilitates weight control, partly through effects on appetite regulation. Single bouts of exercise induce a short-term energy deficit without stimulating compensatory effects on appetite, whilst limited evidence suggests that exercise training may modify subjective and homeostatic mediators of appetite in directions associated with enhanced meal-induced satiety. However, a large variability in responses exists between individuals. This article reviews the evidence relating to how adiposity, sex, and habitual physical activity modulate exercise-induced appetite, energy intake, and appetite-related hormone responses. The balance of evidence suggests that adiposity and sex do not modify appetite or energy intake responses to acute or chronic exercise interventions, but individuals with higher habitual physical activity levels may better adjust energy intake in response to energy balance perturbations. The effect of these individual characteristics and behaviours on appetite-related hormone responses to exercise remains equivocal. These findings support the continued promotion of exercise as a strategy for inducing short-term energy deficits irrespective of adiposity and sex, as well as the ability of exercise to positively influence energy balance over the longer term. Future well-controlled studies are required to further ascertain the potential mediators of appetite responses to exercise.

Background:This study examined the effect of accumulating short bouts of exercise on postprandial plasma triacylglycerol and resting blood pressure in healthy young men.Methods:Nineteen subjects underwent two 2-d trials in a randomized counterbalanced order. On day 1, subjects either rested or performed multiple 6 min running bouts (30 min rest between each) until they had accumulated an energy expenditure of 4.2 MJ (1000 kcal). On day 2, subjects rested and consumed test meals for breakfast and lunch. Blood pressure was measured throughout days 1 and 2. Venous blood samples were obtained throughout day 2.Results:Systolic and diastolic blood pressure was lower for the exercise compared with the control trial on day 1. Postprandial plasma triacylglycerol concentrations and systolic blood pressure were lower throughout day 2 on the exercise compared with the control trial.Conclusion:Accumulating short bouts of exercise throughout the day may modify cardiovascular disease risk.

Accumulating multiple short bouts of exercise throughout the day effectively reduce postprandial plasma triacylglycerol concentrations to an extent similar to that of a single 30-min session of exercise in healthy young men.

OBJECTIVETo examine sex-specific black/white differences in lipoprotein profile and the role of visceral adiposity and to assess the relationship between insulin sensitivity and lipoprotein profiles in each group.RESEARCH DESIGN AND METHODSFasting lipoprotein particle size and concentration and visceral adipose tissue (VAT) were determined in 226 children (117 black, 101 male) aged 8 to <18 years. The relationship between lipoproteins and insulin sensitivity was evaluated in a subset of 194 children (100 black, 88 male) who underwent a hyperinsulinemic-euglycemic clamp.RESULTSBlack male children had smaller VLDL and black female children had larger HDL size than their white counterparts. Overall, blacks had larger LDL size with no sex-specific race differences. After adjusting for VAT and sex, only VLDL size and concentrations remained significantly favorable in blacks. Analysis of lipoprotein particle size and concentration across insulin sensitivity quartiles revealed that in both racial groups, the most insulin-resistant children had higher concentrations of small dense LDL, small HDL, and large VLDL and smaller LDL and HDL sizes than their more insulin-sensitive counterparts.CONCLUSIONSThe previously reported favorable lipoprotein profiles in black versus white children is partly due to race differences in VAT. In both groups, however, the most insulin-resistant youths have a high-risk atherogenic profile of small dense LDL, small HDL, and large VLDL, akin to the atherogenic lipoprotein pattern in adults with coronary artery disease.

Ghrelin is a hormone stimulating hunger. Intense exercise has been shown to temporarily suppress hunger post-exercise. The present study investigated whether post-exercise hunger suppression is mediated by reduced plasma total ghrelin concentrations. Nine men and nine women participated in this study. Age, body mass index and maximal oxygen uptake (max O V 2 &) of the participants (mean ± x s) were: 24.8 ± 0.9 yr, 22.9 ± 0.6 kg•m 2 and 57.7 ± 2.2 mL•kg-1 •min-1. Participants completed two, three-hour trials (exercise and control) on separate days in a randomised balanced design after overnight fasts. The exercise trial involved a one-hour treadmill run at 73.5% of max O V 2 & followed by two hours of rest. The control trial involved three hours of rest. Blood samples were collected at 0, 0.5, 1, 1.5, 2 and 3 hours. Total ghrelin concentrations were determined from plasma. Hunger was assessed following blood samples using a 15-point scale. Data were analysed via repeated measures ANOVA. Hunger scores were lower in the exercise trial compared with the control trial (Trial P=0.009; Time P<0.001; Interaction P<0.001). Plasma total ghrelin concentrations did not differ between trials. These findings indicate that treadmill running suppresses hunger but this effect is not mediated by changes in plasma total ghrelin concentration.

OBJECTIVEOverweight in youth is associated with the risk of developing type 2 diabetes. We hypothesized that β-cell function relative to insulin sensitivity decreases with increasing 2-h glucose levels based on an oral glucose tolerance test (OGTT) in overweight youth.RESEARCH DESIGN AND METHODSA total of 147 overweight (BMI ≥85th percentile for age and sex) youth, aged 8 to <20 years, undertook three tests: 1) a 3-h hyperinsulinemic-euglycemic clamp; 2) a 2-h hyperglycemic clamp; and 3) a 2-h OGTT. Participants were categorically assigned to five groups according to their OGTT 2-h plasma glucose level, ranging from <120 to ≥200 mg/dL. β-Cell function relative to insulin sensitivity, assessed by clamp disposition index (DI) and oral disposition index (DIO), were compared among groups.RESULTSInsulin sensitivity, first-phase insulin, and DI declined significantly as 2-h glucose concentrations increased. The highest DI was found in youth with 2-h plasma glucose concentrations <120 mg/dL, with a significant decline of ~40% in those with glucose concentrations between 120 and <140 mg/dL, and an ~75% decline, the lowest DI, in youth with glucose concentrations ≥200 mg/dL. Data were similar with regard to the OGTT DIO.CONCLUSIONSThese data in overweight youth demonstrate that impairment in insulin secretion relative to insulin sensitivity is apparent even with normal glucose tolerance. Below the current cutoff of 140 mg/dL for impaired glucose tolerance, there is a >30% decline in β-cell function relative to insulin sensitivity. Against this back drop of metabolically heightened risk for type 2 diabetes, preventive measures should target the β-cell alongside insulin sensitization.