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Androgenic responses to resistance exercise: effects of feeding and L-carnitine


Kraemer, WJ and Spiering, BA and Volek, JS and Ratamess, NA and Sharman, MJ and Rubin, MR and French, DN and Silvestre, R and Hatfield, DL and VanHeest, JL and Vingren, JL and Judelson, DA and Deschenes, MR and Maresh, CM, Androgenic responses to resistance exercise: effects of feeding and L-carnitine, Medicine and Science in Sports and Exercise, 2006 Oct, (38(7)) pp. 1288-1296. ISSN 0195-9131 (2006) [Refereed Article]

DOI: doi:10.1249/01.mss.0000227314.85728.35


PURPOSE: The purpose of this investigation was to determine the effects of 3 wk of L-carnitine L-tartrate (LCLT) supplementation and post-resistance-exercise (RE) feeding on hormonal and androgen receptor (AR) responses. METHODS: Ten resistance-trained men (mean+/-SD: age, 22+/-1 yr; mass, 86.3+/-15.3 kg; height, 181+/-11 cm) supplemented with LCLT (equivalent to 2 g of L-carnitine per day) or placebo (PL) for 21 d, provided muscle biopsies for AR determinations, then performed two RE protocols: one followed by water intake, and one followed by feeding (8 body mass, consisting of 56% carbohydrate, 16% protein, and 28% fat). RE protocols were randomized and included serial blood draws and a 1-h post-RE biopsy. After a 7-d washout period, subjects crossed over, and all experimental procedures were repeated. RESULTS: LCLT supplementation upregulated (P<0.05) preexercise AR content compared with PL (12.9+/-5.9 vs 11.2+/-4.0 au, respectively). RE increased (P<0.05) AR content compared with pre-RE values in the PL trial only. Post-RE feeding significantly increased AR content compared with baseline and water trials for both LCLT and PL. Serum total testosterone concentrations were suppressed (P<0.05) during feeding trials with respect to corresponding water and pre-RE values. Luteinizing hormone demonstrated subtle, yet significant changes in response to feeding and LCLT. CONCLUSION: In summary, these data demonstrated that: 1) feeding after RE increased AR content, which may result in increased testosterone uptake, and thus enhanced luteinizing hormone secretion via feedback mechanisms; and 2) LCLT supplementation upregulated AR content, which may promote recovery from RE.

Item Details

Item Type:Refereed Article
Keywords:Androgen Receptor, Endocrine, Supplements, Testosterone, Trophic Hormones
Research Division:Health Sciences
Research Group:Sports science and exercise
Research Field:Exercise physiology
Objective Division:Health
Objective Group:Evaluation of health and support services
Objective Field:Evaluation of health and support services not elsewhere classified
UTAS Author:Sharman, MJ (Dr Matt Sharman)
ID Code:78928
Year Published:2006
Web of Science® Times Cited:62
Deposited By:Health Sciences A
Deposited On:2012-08-07
Last Modified:2012-08-07

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