1 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet2 Section of Systems Biology Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet3 Rigshospitalet, Copenhagen Muscle Research Centre4 Bispebjerg Hospital, Institute of Sports Medicine Copenhagen and Centre for Human Aging5 Saga Nutraceuticals Research Institute, Otsuka Pharmaceutical, Saga, Japan6 Research Unit 247, Ribe County Hospital Esbjerg, Esbjerg, Denmark.7 Institute of Sports Medicine, Bispebjerg Hospital,Copenhagen,Denmark.8 Section of Systems Biology Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet9 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet
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.Conclusion. In early postmenopausal women, nutrient ingestion following resistance exercise improved anabolism by enhancing NB in skeletal muscle.
Journals of Gerontology. Series A, Biological Sciences and Medical Sciences, 2005, Vol 60, Issue 9, p. 1212-1218