Estradiol β Receptor Expression on Human B-lymphocytes in Response to Acute Heavy Resistance Exercise Maren S. Fragala 1,2 , William J. Kraemer 2 , Megan R. Wolf 2 , Andrea M. Mastro 3 , Craig R. Denegar 2 , Jeff S. Volek 2 , Jay R. Hoffman 1 and Carl M. Maresh 2
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Acute Heavy Resistance Exercise
Maren S. Fragala1,2, William J. Kraemer 2, Megan R. Wolf 2, Andrea M. Mastro3, Craig R. Denegar2, Jeff S. Volek2, Jay R. Hoffman 1 and Carl M. Maresh2
1 Human Performance Laboratory, University of Central Florida, Orlando, FL, 2 Human Performance Laboratory, University of Connecticut, Storrs, CT, 3 Department of Microbiology and Cell Biology, The Pennsylvania State University, University Park, PA
Background: Estradiol has previously been attributed for mediating gender differences in physiological responses to tissue damage. Since the neuro-endocrine and immune systems coordinate the body’s response to such stress, we hypothesized that estradiol β-receptors (ER) on b-lymphocytes may coordinate such communications and explain the protective responses previously reported in women.
Purpose: The purpose of this investigation was to examine ER expression on circulating B-lymphocytes in response to an acute bout of heavy resistance exercise in men and women.
Methods:Using a within subject design, fifteen resistance trained women (n=7; age= 22±3 y) and men (n=8; age= 25±5 y) performed a heavy resistance exercise squat protocol (6 sets of 5 reps at 90% 1RM) (EX) and a control test (CON) in a balanced, randomized order. Blood samples were collected before, during and after the exercise and control trials. ER expression on circulating lymphocytes was evaluated with flow cytometryand serum estradiol was assayed by ELISA.
Results:Serum estradiol did not significantly differ between men (CON=48.0±22.3 pg•ml-1) and women (CON=86.5 ± 60.5 pg•ml-1) nor change during recovery to the exercise stress in men (6 HR POST-EX = 49.7±13.6 pg•ml-1; 24 HR POST-EX=60.1 ± 15.1 pg•ml-1) or women (6 HR POST-EX = 73.9±35.8 pg•ml-1; 24 HR POST-EX=105.4 ± 66.9 pg•ml-1) . ER on b-lymphocytes showed large inter-individual variations before exercise (relative fluorescence = 22.3 - 28.8) and trends for differences at 6-hours post-exercise (relative fluorescence = 32.1 - 54.4). However, no significant gender differences or changes in response to the exercise protocol were observed.
Conclusion:Present findings reveal that estradiol-β receptors on B-lymphocytes unlikely explain gender differences in physiological responses to tissue damage elicited by acute heavy resistance exercise. It is possible that interactions may occur beyond the recovery period measured in the present study or it may be that ER on muscle tissue, rather than B-lymphocytes, dictate the protective effects of estradiol previously reported in women.
Figure 4.Circulating Estradiol (pg·mL-1) responses to heavy resistance exercise (squat protocol) (solid lines) and a control condition (dashed lines) in women (n=7) (◊) and men (n=8) (□). Data are presented as means + SEM.
6 sets x 5 reps @ 90% of 1-RM
SUMMARY & CONCLUSIONS
Figure 5.B-lymphocytes (CD19+) expressing estradiol receptors in response to heavy resistance exercise (squat protocol) (solid bars) and a control condition (dashed bars) in women (n=7) (red) and men (n=8) (blue). Data are percentages of cells positively stained for CD19+ and ER+.
Table 1.Participant Characteristics
Blood processing for analysis
*p <0.05 between men and women
‡ Indicates statistical significance (p < 0.05) from corresponding control condition value.
Figure 6.Estradiol β receptor expression (relative fluorescence) in response to heavy resistance exercise (squat protocol) on B-lymphocytes
Blood sample collection during the control trial
Figure 3. Leukocytes were gated based on forward and side scatter characteristics of cells.
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Cell Injector Tip
To examine whether estradiol β receptors on B-lymphocytes change in response to acute exercise stress
To examine whether gender differences in estradiol β receptors expressed on B-lymphocytes exist in response to acute exercise stress are apparent.
Side Scatter &
Resistance exercise protocol