Postexercise nutrient intake enhances leg protein balance in early postmenopausal women.
BACKGROUND
We investigated the effect of nutrient administration after a session of resistance exercise on muscle protein kinetics in six healthy, early postmenopausal women, in a crossover design of random and double-blinded administration of protein and carbohydrate (PC) or placebo (NON).


METHODS
Fasted participants received a primed-constant infusion of L-[ring-2H5]-phenylalanine. After 90 minutes of rest, the participants performed leg-resistance exercises followed by the oral supplementation. During the following 4 hours, net protein balance (NB) and rate of disappearance and appearance of phenylalanine were calculated from arterial-venous blood samples and blood flow measurements.


RESULTS
NB was elevated (p <.001) in the PC group compared to the NON group, and NB was not different from zero in the PC group, whereas it was negative in the NON group. Net balance results were supported by kinetic data from a reduced number of participants, showing that rate of disappearance was responsible for the initial (<1 hour) effect of PC, whereas a reduced rate of appearance enhanced the NB from 1.5 to 3 hours after training in the PC group.


CONCLUSIONS
In early postmenopausal women, nutrient ingestion following resistance exercise improved anabolism by enhancing NB in skeletal muscle.
Holm
Lars
L
Institute of Sports Medicine, Copenhagen, Bispebjerg Hospital, Bld. 8 1st Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark. lh17@bbh.hosp.dk
Esmarck
Birgitte
B
Suetta
Charlotte
C
Matsumoto
Keitaro
K
Doi
Tatsuya
T
Mizuno
Masao
M
Miller
Benjamin F
BF
Kjaer
Michael
M
D004734:Energy Metabolism / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D009747:Nutritional Physiological Phenomena / Q000502:physiology*; D017698:Postmenopause / Q000502:physiology*; D011506:Proteins / Q000378:metabolism*; D012016:Reference Values
D011506:Proteins