This US-Poland Marie Sklodowska-Curie Joint Fund research project between Dr. Hanna Kaciuba-Uscilko of the Department of Applied Physiology, Medical Research Center, Polish Academy of Sciences, Warsaw, and Dr. Ronald L. Terjung, Department of Physiology, State University of New York, Syracuse, is on "Mechanisms Controlling Intramuscular Lipid Metabolism." Skeletal muscles play an important role in the whole lipid metabolism since they remove a considerable amount of circulating lipids that are partly oxidized and partly stored, forming an intramuscular triacylglycerol (TG) pool. However, contribution of intramuscular TG to energy metabolism at rest and during exercise as well as systemic and local mechanisms controlling TG synthesis and utilization in muscle cells are poorly recognized. The purposes of the planned study are: (1) to elaborate an adequate system for quantitative estimation of intramuscular TG metabolic turnover; (2) to determine an influence of muscle contractions of different intensity and duration on the rate of synthesis and utilization of intramuscular TG, and to estimate TG contribution to exercise energy metabolism; (3) to investigate the effects of physical training, nutritional status, dietary modifications and some hormones on the intramuscular TG metabolism; (4) to evaluate interactions between the systems controlling intramuscular TG metabolism, the mechanisms of lipid removal from the plasma by skeletal muscles and the whole body lipid metabolism. The results are supposed to enlarge the understanding of metabolic adaptation to physical work, and dietary modifications and the role of physiological factors in prevention and therapy of some lipid metabolism disturbances-- e.g., atherosclerosis, obesity. This project in physiology fulfills the program objective of advancing scientific knowledge by enabling leading experts in Poland and the United States to combine complementary talents and pool resources in areas of strong mutual interest and competence.