Differential stimulation of myofibrillar and sarcoplasmic protein synthesis with protein ingestion at rest and after resistance exercise

作者：Daniel R. Moore, Jason E. Tang, Nicholas A. Burd, Tracy Rerecich, Mark Andrew Tarnopolsky, Stuart M. Phillips · 发表于：The Journal of Physiology · 年份：2009 · DOI：10.1113/jphysiol.2008.164087 · 被引用次数：325 · 研究领域：Muscle metabolism and nutrition、Sports Performance and Training、Exercise and Physiological Responses

We aimed to determine whether there is a differential stimulation of the contractile myofibrillar and the cellular sarcoplasmic proteins after ingestion of protein and how this is affected by resistance exercise. Fasted (FAST) muscle protein synthesis was measured in seven healthy young men with a primed constant infusion of L-[ring-(13)C(6)]phenylalanine. Participants then performed an intense bout of unilateral resistance exercise followed by the consumption of 25 g of whey protein to maximally stimulate protein synthesis. In the rested (FED) leg myofibrillar (MYO) protein synthesis was elevated (P < 0.01) above FAST at 3 h (approximately 163%) but not at 1 and 5 h (P > 0.05). In contrast, MYO protein synthesis in the exercised (FED-EX) leg was stimulated above FAST at 1, 3 and 5 h (approximately 100, 216, and 229%, respectively; P < 0.01) with the increase at 5 h being greater than FED (P < 0.01). Thus, the synthesis of muscle contractile proteins is stimulated by both feeding and resistance exercise early (1 h) but has a greater duration and amplitude after resistance exercise. Sarcoplasmic (SARC) protein synthesis was similarly elevated (P < 0.01) above FAST by approximately 104% at 3 h in both FED and FED-EX suggesting SARC protein synthesis is stimulated by feeding but that this response is not augmented by resistance exercise. In conclusion, myofibrillar and sarcoplasmic protein synthesis are similarly, but transiently, stimulated with protein feeding. In contrast, re...