No effect of menstrual cycle on myofibrillar and connective tissue protein synthesis in contracting skeletal muscle.
We tested the hypothesis that acute exercise would stimulate synthesis of myofibrillar protein and intramuscular collagen in women and that the phase of the menstrual cycle at which the exercise took place would influence the extent of the change. Fifteen young, healthy female subjects were studied in the follicular (FP, n=8) or the luteal phase (LP, n=7, n=1 out of phase) 24 h after an acute bout of one-legged exercise (60 min of kicking at 67% W(max)), samples being taken from the vastus lateralis in both the exercised and resting legs. Rates of synthesis of myofibrillar and muscle collagen proteins were measured by incorporation of [(13)C]leucine. Myofibrillar protein synthesis (means+/-SD; rest FP: 0.053+/-0.009%/h, LP: 0.055+/-0.013%/h) was increased at 24-h postexercise (FP: 0.131+/-0.018%/h, P<0.05, LP: 0.134+/-0.018%/h, P< 0.05) with no differences between phases. Similarly, muscle collagen synthesis (rest FP: 0.024+/- 0.017%/h, LP: 0.021+/- 0.006%/h) was elevated at 24-h postexercise (FP: 0.073+/- 0.016%/h, P<0.05, LP: 0.072+/- 0.015%/h, P<0.05), but the responses did not differ between menstrual phases. Therefore, there is no effect of menstrual cycle phase, at rest or in response to an acute bout of exercise, on myofibrillar protein synthesis and muscle collagen synthesis in women.
Miller
Benjamin F
BF
Institute of Sports Medicine, Copenhagen. b.miller@auckland.ac.nz
Hansen
Mette
M
Olesen
Jens L
JL
Flyvbjerg
Allan
A
Schwarz
Peter
P
Babraj
John A
JA
Smith
Kenneth
K
Rennie
Michael J
MJ
Kjaer
Michael
M
D000328:Adult; D003238:Connective Tissue / Q000378:metabolism; D004967:Estrogens / Q000097:blood; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D005260:Female; D024022:Fibrillar Collagens / Q000096:biosynthesis*; D005498:Follicular Phase / Q000378:metabolism; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008183:Luteal Phase / Q000378:metabolism; D008297:Male; D008597:Menstrual Cycle / Q000502:physiology; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology; D009210:Myofibrils / Q000378:metabolism; D011374:Progesterone / Q000097:blood; D012737:Sex Factors
D004967:Estrogens; D024022:Fibrillar Collagens; D018969:Insulin-Like Growth Factor Binding Proteins; D009124:Muscle Proteins; D011374:Progesterone; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II