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Published in: Sport Sciences for Health 3/2018

01-12-2018 | Original Article

12-week treadmill exercise program elicits lower energy availability without changes in serum testosterone in male rats

Authors: Lyra R. Clark, Michael J. Dellogono, Erin E. Chenette, Kelsey M. Mangano, Thomas A. Wilson

Published in: Sport Sciences for Health | Issue 3/2018

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Abstract

Purpose

The purpose of this study was to investigate whether a treadmill endurance exercise program would reduce serum testosterone and leptin in male rats and assess the impact of increased dietary cholesterol on serum hormones.

Methods

Male Sprague-Dawley Rats (n = 20) were randomly assigned to a control group (C) or an exercise training group (EX) that performed treadmill running 40 min/day, 6 days/week for 12 weeks. At study midpoint (week 6), rats were randomized to a high-cholesterol (HC) diet (n = 10) or remain on standard semi-purified (LC) diet (n = 10).

Results

Results are presented as median [IQR]. At end of week 6, EX + LC had significantly lower body weight (508 [460–527] vs 570 [516–606] g; p = 0.01), mean daily energy intake (76.3 [74.9–82.2] vs 90.9 [86.9–94.5] kcal; p < 0.01), and serum leptin (0.4 [0.3–0.6] vs 3.3 [2.0–4.0] ng/mL; p < 0.01) in comparison to C + LC. No difference was observed between EX + LC and C + LC in serum testosterone (12.6 [6.9–18.3] vs 11.7 [7.6–18.9] ng/mL). At end of week 12, EX + LC had significantly lower body weight (514 [483–568] g) compared to C + LC (644 [575–680] g; p < 0.01) and C + HC (650 [583–702] g; p < 0.01). Serum Leptin in both EX + LC (0.6 [0.2–0.8] ng/mL) and EX + HC (0.6 [0.3–1.6] ng/mL) was significantly lower than C + LC (3.0 [2.2–4.2] ng/mL; p < 0.01). No significant difference in testosterone was observed between C + LC and C + HC (4.3 [3.3–8.3] vs 6.3 [3.2–9.3] ng/mL, respectively).

Conclusions

Despite lower energy availability, exercise-induced changes in sex hormones may not occur in training programs ≤ 12 weeks. Lower voluntary energy intake observed in exercise groups despite greater energy expenditure may indicate that lower energy availability in endurance-trained individuals may be inadvertent.
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Metadata
Title
12-week treadmill exercise program elicits lower energy availability without changes in serum testosterone in male rats
Authors
Lyra R. Clark
Michael J. Dellogono
Erin E. Chenette
Kelsey M. Mangano
Thomas A. Wilson
Publication date
01-12-2018
Publisher
Springer Milan
Published in
Sport Sciences for Health / Issue 3/2018
Print ISSN: 1824-7490
Electronic ISSN: 1825-1234
DOI
https://doi.org/10.1007/s11332-018-0455-0

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