Protein synthesis in skeletal muscle following acute exhaustive exercise

Abstract

Cell-free and whole-tissue protein synthesis was studied in skeletal muscle of untrained male guinea pigs that had undergone a treadmill run to exhaustion. Experiments using explants from the gastrocnemius muscle maintained in organ culture demonstrated that the ability of the acutely exercised muscle to incorporate amino acids into protein had increased. Compared to polyribosomes prepared from several lower hind limb muscles of nonexercised guinea pigs, polyribosomes from the same muscle in exhausted guinea pigs had incorporated almost 50% more radioactive leucine into protein. However, the polysome profiles of control and exercised muscle were identical, and no difference in the total polysome RNA content could be detected. The efficiency of in-vitro protein synthesis using washed membranebound polyribosomes (microsomes) isolated from acutely exercised skeletal muscle was 50% greater than with microsomes from rested control muscle. MUSCLE & NERVE 2~250-256 1979 PROTEIN SYNTHESIS IN SKELETAL MUSCLE FOLLOWING ACUTE EXHAUSTIVE EXERCISE PETER A. ROGERS, BSc, GEORGE H. JONES, PhD, and JOHN A. FAULKNER. PhDT h e protein synthesis system in mature mammalian skeletal muscle demonstrates the capacity to respond and adapt to various pathologic states as well as to changes in functional demand. For example, various differences in the ribosomal capacity for protein synthesis have been observed in several types of muscular dystrophy,6 and diabetes decreases the capacity of skeletal muscle to synthesize protein in vitro9 and in ~i v o .~ Microsomal and ribosornal protein synthesis is decreased in the skeletal muscles of rats after four to six days of protein starvation, and is enhanced after a single meal of protei11.l~ The effects of changes in dietary regimen can be detected in vivo as well,'o and these studies have correlated well with in-vitro results.

Guinea pig models for translation of the developmental origins of health and disease hypothesis into the clinic

“…; Rogers et al . ) and hepatic glucose production in denervated livers (Wiersma et al . ), the latter because of rich liver innervation comparable to humans and in contrast to rat and dog.…”

Postexercise recovery period: carbohydrate and protein metabolism

“…The studies of whole-body metabolism in humans point to nitrogen retention in the recovery period (71, Viru 72). The postexercise intensification of protein synthesis was proved by the elevated rate of amino acid incorporation into various fractions of skeletal muscle proteins (73)(74)(75) as well as by enhanced incorporation of labeled precursors into RNA (76). Accordingly, increases in the ribosomal translational activity (73) and nuclear RNA polymerase activity (77) were detected in the recovery period.…”