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Kraemer RR, Castracane VD. Novel insights regarding mechanisms for treatment of sarcopenia. Metabolism 2015; 64:160-2. [PMID: 25467382 DOI: 10.1016/j.metabol.2014.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 11/05/2014] [Indexed: 01/05/2023]
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Russell RD, Nelson AG, Kraemer RR. Short Bouts of High-Intensity Resistance-Style Training Produce Similar Reductions in Fasting Blood Glucose of Diabetic Offspring and Controls. J Strength Cond Res 2014; 28:2760-7. [DOI: 10.1519/jsc.0000000000000624] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Thomas JF, Larson K, Hollander DB, Kraemer RR. Comparison of Kettlebell Exercises and Graded Treadmill Walking. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000493984.94993.d7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kraemer RR, Shockett PE, Webb ND, Shah U, Castracane VD. A Transient Elevated Irisin Blood Concentration in Response to Prolonged, Moderate Aerobic Exercise in Young Men and Women. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000494385.02684.8b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Thomas JF, Larson KL, Hollander DB, Kraemer RR. Comparison of Two-Hand Kettlebell Exercise and Graded Treadmill Walking. J Strength Cond Res 2014; 28:998-1006. [DOI: 10.1519/jsc.0000000000000345] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kraemer RR, Shockett P, Webb ND, Shah U, Castracane VD. A transient elevated irisin blood concentration in response to prolonged, moderate aerobic exercise in young men and women. Horm Metab Res 2014; 46:150-4. [PMID: 24062088 DOI: 10.1055/s-0033-1355381] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Irisin, a newly discovered, PGC-1α dependent myokine, has recently been shown to increase in circulation in response to sprint exercise. This study examined the effect of prolonged exercise on irisin concentrations in young men (n=7) as well as in young women (n=5) during different stages of the menstrual cycle. Seven young men completed 90 min of treadmill exercise at 60% of VO2max and a resting control trial. Five women completed the same exercise protocol in two different trials: during the early follicular phase and mid-luteal phase of the menstrual cycle. Blood samples were collected and analyzed for irisin concentrations immediately before exercise, at 54 and 90 min of exercise, and at 20 min of recovery (R20). Findings revealed that by 54 min of a 90 min treadmill exercise protocol at 60% of VO2max, irisin concentrations significantly increased 20.4% in young men and 20.3% as well as 24.6% in young women during the early follicular and mid-luteal phases of the menstrual cycle, respectively. However, by 90 min of exercise as well as R20, irisin concentrations were no longer elevated. Stage of the menstrual cycle did not affect responses in young women. Findings indicate that prolonged aerobic exercise produces a transient increase in irisin concentrations during the first hour of exercise for both genders and suggest that this form of moderate exercise may be helpful in improving fat metabolism.
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Kraemer RR, Francois M, Webb ND, Worley JR, Rogers SN, Norman RL, Shah U, Castracane VD. No effect of menstrual cycle phase on glucose and glucoregulatory endocrine responses to prolonged exercise. Eur J Appl Physiol 2013; 113:2401-8. [PMID: 23765198 DOI: 10.1007/s00421-013-2677-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 06/01/2013] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Prolonged exercise requires increased utilization of blood glucose and adjustment of glucoregulatory hormones. Estrogen can reduce hepatic gluconeogenesis which could affect insulin concentrations. Amylin is co-secreted with insulin and controls influx of glucose into the blood. PURPOSE To determine the effect of menstrual cycle stage on glucose, leptin, and pancreatic hormone responses to prolonged (90 min) exercise. METHODS Five healthy, eumenorrheic women (24.6 ± 5.1 years; 67.4 ± 1 kg) were monitored for 3 months to determine menstrual cycle length. Subjects completed a preliminary session to determine exercise workloads and, in a fasted condition, completed two randomized 90-min treadmill exercise trials at 60 % VO2max during the early follicular (EFX) and mid-luteal phase (MLX) of their menstrual cycle. Blood samples were analyzed for glucose, insulin, C-peptide, amylin, glucagon, leptin, and cortisol concentrations at rest (-30 and 0 min), during exercise (18, 36, 54, 72, and 90 min) and after 20 min of recovery. RESULTS No changes in amylin, leptin, or cortisol occurred for EFX and MLX trials. A significant (p < 0.05) time effect occurred for glucose, insulin, and glucagon with reduced insulin across the exercise trial and increases in glucose and glucagon later in the trial, but there were no differences between the EFX and MLX trials. CONCLUSIONS Menstrual cycle stage does not affect glucose, insulin, C-peptide, amylin, glucagon, cortisol, and leptin responses to prolonged exercise; however, the exercise reduces insulin and increases glucose and glucagon concentrations. This is the first study to determine acute effects of exercise on amylin and other glucoregulatory hormone responses in women.
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Russell RD, Kraemer RR, Nelson AG. Metabolic dysfunction in diabetic offspring: deviations in metabolic flexibility. Med Sci Sports Exerc 2013; 45:8-15. [PMID: 22811035 DOI: 10.1249/mss.0b013e31826909d3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED In type 2 diabetes (T2D), insulin resistance is related to comorbidities, including high lipotoxicity, poor glucoregulation, and loss of metabolic flexibility. Controversy exists regarding whether reduced metabolic flexibility precedes insulin resistance or vice versa. PURPOSE The purpose of this study was to determine whether a family history of T2D leads to metabolic inflexibility. METHODS To examine potential loss of metabolic flexibility at early stages, we used a hooded metabolic cart to compare metabolic characteristics in people with T2D, family history of T2D (FH+), and controls (FH-) 1) at rest, 2) with passive stretching (PS) and recovery, and 3) with oral glucose load. Testing of 9 T2D, 11 FH+, and 9 FH- occurred after a 12-h fast under resting conditions. Expired gas and blood glucose (BG) were measured before and after each condition. RESULTS PS lowered BG (P < 0.05) in FH- and FH+ (mean ± SD, -2.7 ± 5.9 and -5.8 ± 7.5 mg·mL(-1)) compared with T2D (-0.9 ± 7.7). CHO use (kcal·min(-1)) increased with PS in all groups (0.04 ± 0.18, 0.03 ± 0.26, and 0.22 ± 1.6 mg·mL(-1) in FH-, FH+, and T2D, respectively). For oral glucose load, different metabolic flexibility existed between FH- as well as FH+ (0.16 ± 0.07) as well as T2D (0.16 ± 0.07), with no difference between FH- and T2D. CONCLUSION PS increases glycolytic activity without affecting BG in T2D, and reductions in metabolic flexibility exist in T2D and FH+ without glucoregulatory impairment in FH+, indicating early stage of mitochondrial dysfunction in FH+. Findings indicate PS is an important tool for assessing metabolic flexibility.
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Kraemer RR, Castracane VD, Francois M, Ghanbari-Niaki A, Sirikul B, Valverde RA. Effects of prolonged exercise on agouti-related protein: a pilot study. Endocrine 2012; 42:436-41. [PMID: 22477065 DOI: 10.1007/s12020-012-9663-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/22/2012] [Indexed: 10/28/2022]
Abstract
Agouti-related protein (AgRP), is a signaling peptide that affects feeding behavior, energy homeostasis, and has also been shown to stimulate the hypothalamic-pituitary-adrenal axis. The purpose of this study was to determine the effects of 90 min of treadmill exercise on circulating AgRP concentrations and the relationship of AgRP responses to cortisol. Seven young males completed a preliminary trial followed by counterbalanced experimental and control trials 4-5 weeks apart. The experimental trial began 2.5 h after consumption of a standard nutrient beverage and consisted of treadmill exercise at 60 % of previously determined VO(2max) for 90 min. Blood samples were collected before (-30 and 0 min), during (18, 36, 54, 72, and 90 min), and following exercise (20, 40, and 60 min). Blood samples were collected in a resting, control trial at the same time points as the experimental trial. Plasma lactate was significantly higher in the exercise than the control trial. Although AgRP increased from 18 min of exercise to peak at 90 min, these increases were not significantly different than values in the control trial. Cortisol responses during the exercise trial were significantly higher than the control trial. AgRP concentrations during early exercise were positively correlated with cortisol levels later in recovery. The obtained data suggest that AgRP concentrations during prolonged steady-state exercise are associated with subsequent cortisol increases, but further study is required to determine whether there is a causal effect.
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Kraemer RR, Francois M, Castracane VD. Estrogen mediation of hormone responses to exercise. Metabolism 2012; 61:1337-46. [PMID: 22512823 DOI: 10.1016/j.metabol.2012.03.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 03/15/2012] [Accepted: 03/15/2012] [Indexed: 10/28/2022]
Abstract
The roles of estrogens extend from the regulation of reproduction to other functions involved in control of metabolism, fluid balance, as well as gastrointestinal, lung, and brain function, with a strong effect on other hormones that subsequently alter the physiology of multiple tissues. As such, alteration of endogenous estrogens across the menstrual cycle, or from oral contraception and estrogen replacement therapy, can affect these tissues. Due to the important effects that estrogens have on different tissues, there are many investigations concerning the effects of a human estrogenic environment on endocrine responses to exercise. The following review will describe the consequences of varying estrogen levels on pituitary, adrenal, gonadal, and endocrine function, followed by discussion of the outcomes of different estrogen levels on endocrine tissues in response to exercise, problems encountered for interpretation of findings, and recommended direction for future research.
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Kraemer RR, Francois MR, Sehgal K, Sirikul B, Valverde RA, Castracane VD. Amylin and selective glucoregulatory peptide alterations during prolonged exercise. Med Sci Sports Exerc 2011; 43:1451-6. [PMID: 21266924 DOI: 10.1249/mss.0b013e3182114ab9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
UNLABELLED Amylin is a pancreatic β-cell peptide that facilitates the regulation of blood glucose concentration by inhibiting release of glucagon and modulating gastric emptying. Prolonged exercise may alter amylin and aid in the maintenance of blood glucose concentration; however, no studies have investigated the effects of prolonged exercise on amylin. PURPOSE This study aimed to determine the effects of 90 min of treadmill exercise on amylin and other glucoregulatory hormone responses in a postprandial state. METHODS Eight young healthy males completed a preliminary trial for VO2max and body composition determination and subsequent experimental and control trials in a counterbalanced manner. The experimental trial subjects arrived at the laboratory at 8:00 a.m., 1 h after consumption of a standard nutrient beverage (Ensure Plus®). At 9:50 a.m., subjects initiated 90 min of treadmill exercise at 60% of VO2max. Blood samples were collected twice before exercise, every 18 min during exercise, and every 20 min during 1 h of recovery. A resting control trial was conducted in an identical manner without VO2 assessment. RESULTS Plasma glucose and leptin concentrations remained stable across exercise, whereas lactate significantly increased to peak at 18 min of exercise then gradually declined. Amylin, insulin, and C-peptide values significantly declined over the trials, with no difference between exercise and control days. Glucagon area-under-the-curve concentrations were significantly greater during the exercise than the control trials. There was a significant time effect and trial effect for cortisol with a higher concentration during the experimental trial than during the control trial. CONCLUSIONS In a postprandial state, prolonged exercise stimulates glucagon and cortisol increases that are associated with stable blood glucose and leptin concentrations; however, similar to postprandial state control condition, insulin, C-peptide, and amylin concentrations decline.
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Webb HE, Fabianke-Kadue EC, Kraemer RR, Kamimori GH, Castracane VD, Acevedo EO. Stress Reactivity to Repeated Low-Level Challenges: A Pilot Study. Appl Psychophysiol Biofeedback 2011; 36:243-50. [DOI: 10.1007/s10484-011-9164-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Ghanbari-Niaki A, Jafari A, Moradi M, Kraemer RR. Short-,moderate-, and long-term treadmill training protocols reduce plasma, fundus, but not small intestine ghrelin concentrations in male rats. J Endocrinol Invest 2011; 34:439-43. [PMID: 21183796 DOI: 10.1007/bf03346710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND It has been suggested that circulating ghrelin levels are upregulated by fasting, hypoglycemic status, and a physical exercise-induced energy deficit. AIM The purpose of the present study was to investigate the timecourse adaptations of the plasma, fundus, and small intestine ghrelin concentrations as well as related hormones and liver ATP levels to 3, 6, and 12 weeks of treadmill endurance running. MATERIAL/SUBJECTS AND METHODS Thirty-nine male Wistar rats (12-14 weeks old) were randomly assigned to 3 control (C3, no.=5; C6, no.=7 and C12, no.=7) and 3 training groups (E3, no.=6; E6, no.=7 and E12, no.=7). The rats in the 3 training groups were exercised on a motor-driven treadmill at 25 m/min (0% grade) for 60 min/day, 5 days/week for 3, 6, and 12 weeks, respectively. The animals were sacrificed 48 h after the last session of each training program and tissues were analyzed. RESULTS Total ghrelin concentrations were significantly (p<0.05) lower in trained rat plasma and fundus tissue after all treadmill endurance running programs. Small intestine ghrelin concentrations remained unchanged. Plasma GH concentrations and liver ATP content were significantly higher in E6 and E12 groups. CONCLUSION Data indicate that as little as 3 weeks of moderate treadmill exercise reduces plasma and fundus total ghrelin concentrations with elevated plasma GH and liver ATP content occurring after 6 and 12 weeks of training. Exercise training-induced improvement of energy source availability and negative feedback from increased GH levels may play a role in reducing plasma and fundus ghrelin levels.
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Kraemer RR, Castracane VD, Francois M, Ghanbari-Niaki A, Valverde RA. Effects Of Prolonged Running On Agouti-related Protein And Cortisol. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402532.90756.7a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kraemer RR. 997. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000403126.23300.79] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Garekani ET, Mohebbi H, Kraemer RR, Fathi R. Exercise training intensity/volume affects plasma and tissue adiponectin concentrations in the male rat. Peptides 2011; 32:1008-12. [PMID: 21291933 DOI: 10.1016/j.peptides.2011.01.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 01/20/2011] [Accepted: 01/21/2011] [Indexed: 01/05/2023]
Abstract
The objective of the study was to determine the effects of exercise training intensity/volume on plasma total and high molecular weight (HMW) adiponectin and tissue total adiponectin concentrations. Thirty-two, eight week-old male Wistar rats (185 ± 5g) were randomly assigned to one of four groups: high intensity (HI: 34 m/min ∼%80-%85 VO(2)max), moderate intensity (MI: 28 m/min ∼%70-%75 VO(2)max), low intensity (LI: 20 m/min ∼ %50-%55 VO(2)max), and sedentary control (SED). Experimental groups completed a 12-week exercise program of treadmill running at 0° slope, 1h/day, 5 days/week. Since frequency and duration of exercise were identical among training groups, the volume of training was highest in the HI group followed by the MI and LI groups. Compared with SED animals, fasting plasma total and HMW adiponectin and adipose tissue total adiponectin concentrations were significantly higher in the HI and MI groups, but total adiponectin concentrations in liver and soleus muscle were not significantly lower than the SED rats. There were significantly lower plasma total testosterone levels in the HI group vs. SED group. Plasma total and HMW adiponectin were negatively correlated with HOMA-IR and insulin whereas total adiponectin was inversely related to TNF-α and HMW adiponectin was negatively correlated with total testosterone. Thus, data suggest there is a dose effect for exercise training intensity and accompanying volume for the adaptation of adipose tissue and circulating total and HMW adiponectin concentrations, whereas the changes of adiponectin concentrations in skeletal muscle and liver tissue may depend on the body's energy balance in the recovery period.
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Worley JR, Rogers SN, Kraemer RR. Metabolic Responses to Wii Fit™ Video Games at Different Game Levels. J Strength Cond Res 2011; 25:689-93. [DOI: 10.1519/jsc.0b013e318207eae9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ghanbari-Niaki A, Kraemer RR, Abednazari H. Time-course alterations of plasma and soleus agouti-related peptide and relationship to ATP, glycogen, cortisol, and insulin concentrations following treadmill training programs in male rats. Horm Metab Res 2011; 43:112-6. [PMID: 21104582 DOI: 10.1055/s-0030-1267998] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
No studies have examined the time-course changes of the appetite stimulating hormone, agouti-related peptide (AgRP), induced by exercise training. The purpose of the study was to determine the effects of short (3 weeks), moderate (9 weeks), and long-term (12 weeks) treadmill training on plasma and soleus concentrations of AgRP, as well as ATP and glycogen concentrations in soleus muscle and liver tissues. 54 Wistar male rats were randomly assigned into control (total n=27; 3 week control=10; 9 week control=8; 12 week control=9) and training (total n=27; 3 week trained=10; 9 week trained=8; 12 week trained=9). The training groups ran for 60 min/d, 5 d/wk at 25 m/min and 0% grade for 3, 9, and 12 weeks. After the last exercise session soleus muscle, liver, and plasma were collected and frozen. Results demonstrated that after 3, 9, and 12 weeks of exercise training there was an increase in plasma and soleus AgRP that declined with age. Soleus muscle glycogen was inversely related to AgRP. After 9 weeks of training there was a significant decrease and increase in plasma insulin and cortisol, respectively. Thus, as little as 3 weeks of running enhances AgRP concentration in rat soleus and plasma whereas changes in liver ATP and glycogen and soleus muscle glycogen require 9 weeks for alteration. Plasma and soleus muscle AgRP decline with age, and AgRP concentration in plasma and soleus are related to insulin, soleus ATP, and liver glycogen.
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Kraemer RR, Castracane D. Effect of acute and chronic exercise on ghrelin and adipocytokines during pubertal development. MEDICINE AND SPORT SCIENCE 2010; 55:156-173. [PMID: 20956867 DOI: 10.1159/000321979] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
It is important to understand the factors that regulate the development of obesity during adolescence due to the increased risk of adult obesity, metabolic syndrome and the deleterious health effects of early puberty which may increase the risk of breast cancer later in life. Leptin, ghrelin, and adiponectin are peptides that affect energy homeostasis and insulin action. Similar to findings in adults, steady-state exercise does not change leptin concentrations and aerobic training without a change in body weight. A small amount of available data suggest that acute exercise does not increase circulating adiponectin concentrations in adolescents; however, it is very possible that more rigorous exercise protocols could acutely affect circulating adiponectin levels. Training studies indicate that shorter lengths of exercise training have a stronger effect on increases in adiponectin concentrations in male than female adolescents. It appears that if training is extended, increases in adiponectin levels will accompany improvements in insulin sensitivity. There are no studies of acute or chronic exercise on high-molecular weight adiponectin in adolescents and since this is thought to be the bioactive form of adiponectin, these studies are definitely needed. Investigations have demonstrated that exercise training increases total ghrelin levels in adolescents and that ghrelin is sensitive to reductions in body fat or increases in energy expenditure in this population. These findings are similar to those in adults. Moreover, there is evidence that luteinizing hormone is a predictor of total ghrelin levels in girls and suggests that ghrelin is a biomarker of energy imbalance across the menstrual cycle.
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Ghanbari-Niaki A, Soltani R, Shemshaki A, Kraemer RR. Effects of acute ethionine injection on plasma ghrelin and obestatin levels in trained male rats. Metabolism 2010; 59:982-7. [PMID: 20045146 DOI: 10.1016/j.metabol.2009.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 10/21/2009] [Accepted: 10/23/2009] [Indexed: 10/20/2022]
Abstract
Ghrelin and obestatin are orexigenic and anorexigenic peptides, respectively, that are secreted from the stomach mucosa into the circulation. These peptides have opposing actions on food intake, weight gain, and adiposity. It is thought that ghrelin is sensitive to a negative energy environment and also plays a considerable role in short- and long-term energy balance and glucose homeostasis. It has been suggested that the levels of ghrelin and obestatin are upregulated by fasting, hypoglycemic status, and a physical-exercise-induced energy deficit. Ethionine (ETH), the ethyl analogue of methionine, has been shown to increase food intake, decrease adenosine triphosphate (ATP) and glycogen levels, and inhibit protein synthesis in the liver. The purpose of this study was to examine the effect of a single dose of ETH (0.7 mg/g of body weight) injection on resting plasma total ghrelin and obestatin concentrations in male trained rats. Thirty-two adult Wistar male rats weighing 180 to 200 g were randomly assigned to control (n = 16) and training (n =16) groups. The training group was exercised for 10 weeks (25 m/min, 0% grade, 60 minutes, and 5 d/wk). Seventy-two hours after the last exercise session, rats were injected with either saline (NaCl) or ETH and then killed. Ethionine compared with a NaCl injection resulted in significant (P < .013) reductions in resting hepatic ATP and glycogen levels, and in a significant (P < .001) increase in concentrations of plasma total ghrelin but not obestatin. The results indicate that ETH-induced liver ATP and glycogen deficiency could exert a powerful regulatory influence on plasma total ghrelin, but this is not the case for obestatin. Findings demonstrate the short-term energy-regulating capacity of ghrelin.
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Fathi R, Ghanbari-Niaki A, Kraemer RR, Talebi-Garakani E, Saghebjoo M. The effect of exercise intensity on plasma and tissue acyl ghrelin concentrations in fasted rats. ACTA ACUST UNITED AC 2010; 165:133-7. [PMID: 20542063 DOI: 10.1016/j.regpep.2010.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2010] [Revised: 05/06/2010] [Accepted: 05/30/2010] [Indexed: 12/13/2022]
Abstract
OBJECTIVE This study was conducted to investigate the effect of exercise training and feeding status on plasma and tissue acyl ghrelin concentrations. MATERIALS AND METHODS Thirty-two, eight-week-old male Wistar rats (185±5g) were randomly assigned to one of four groups: high intensity (HI: 34 m/min ~80-85% VO(2)max), moderate intensity (MI: 28 m/min ~70-75% VO(2)max), low intensity (LI: 20 m/min ~50-55% VO(2)max), and sedentary control (SED) groups. All experimental groups performed a 12-week exercise program consisting of treadmill running on a 0° slope for 1 h/day, 5 days/week at their respective training intensity. Twenty four hours following the last training session the animals completed a 12h fast. Rats were then killed, blood was collected and plasma separated; the fundus and soleus muscle were excised and frozen in liquid nitrogen for later analysis. Fasting levels of circulating acyl ghrelin and acyl ghrelin content in the soleus muscle and fundus, as well as glycogen in the soleus muscle were measured. Data were analyzed using one-way ANOVA. RESULTS Results demonstrated that 12 weeks of exercise training combined with a 12h fast significantly increased plasma as well as soleus muscle concentrations of acyl ghrelin in the HI and MI groups (p<0.05) and reduced acyl ghrelin concentrations in the fundus (p<0.05). CONCLUSION The results of the study indicate that chronic treadmill exercise training enhances fasting plasma acyl ghrelin in an intensity-dependent manner which is accompanied by a significant increase in soleus muscle and reduction in fundus acyl ghrelin levels.
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Worley JR, Rogers SN, Kraemer RR. Metabolic Responses to Wii Fit™ Activity. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000386530.30492.9c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kraemer RR, Francois M, Sehgal K, Sirikul B, Valverde R, Castracane VD. Alterations in Amylin and Glucagon During Prolonged Exercise. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000385986.19996.d1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ghanbari-Niaki A, Saghebjoo M, Rashid-Lamir A, Fathi R, Kraemer RR. Acute circuit-resistance exercise increases expression of lymphocyte agouti-related protein in young women. Exp Biol Med (Maywood) 2010; 235:326-34. [DOI: 10.1258/ebm.2009.009209] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Exercise-induced leukocytosis and lymphocytosis is accompanied by up-regulation and down-regulation of hundreds of genes in white blood cells (WBCs). Agouti-related protein (AgRP) is an orexigenic peptide secreted predominantly from the arcuate nucleus in the hypothalamus. AgRP affects feeding behavior and plays a role in energy and glucose homeostasis and adiposity. The purpose of the study was to determine effects of circuit resistance exercise (CRE) (9 exercises, 25 s per exercise) at different intensities on peripheral blood lymphocyte (PBL) AgRP mRNA expression and its concentrations in lymphocytes and plasma. Twenty-five young female college students were randomly divided into five groups: control, 40% 1-repetition maximum (1-RM), 60% 1-RM, 80% 1-RM and combined (40 + 60 + 80% 1-RM) loads. Peripheral blood mononuclear cells were isolated by a lymphocyte density gradient centrifugation method for AgRP mRNA expression. Lymphocyte ATP, glycogen, AgRP, growth hormone (GH), and plasma AgRP, GH and glucose concentrations were measured. CRE increased AgRP mRNA lymphocyte expression significantly ( P < 0.0001) at all intensities. A higher and significant ( P < 0.01) increase was found in the 60% 1-RM group when compared with the other groups. The CRE-induced lymphocyte AgRP expression was accompanied by elevations in plasma AgRP, glucose and GH levels as well as higher WBCs, lymphocytes and neutrophil counts. Lymphocyte AgRP and GH concentrations were significantly reduced ( P < 0.05). Lymphocyte ATP content was unchanged and glycogen was reduced in the combined group but not in the other groups. Data indicate that AgRP mRNA is expressed in PBLs and that CRE increases its expression. Data also reveal that the expression of AgRP was accompanied with higher plasma AgRP and GH concentrations. Findings suggest that AgRP may provide an important signal in the immune environment and that the lymphocyte may be considered as an extra-hypothalamic source of plasma AgRP following exercise stress.
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Hollander DB, Reeves GV, Clavier JD, Francois MR, Thomas C, Kraemer RR. Partial Occlusion During Resistance Exercise Alters Effort Sense and Pain. J Strength Cond Res 2010; 24:235-43. [DOI: 10.1519/jsc.0b013e3181c7badf] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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