FNDC5 and Alzheimer disease: For example, human skeletal muscle releases myokines into the bloodstream during exercise that influence the brain, liver, and adipose tissue.88, 89 Myokines, including the interleukins IL-6, IL-7, and IL-15 regulate metabolic processes such as hepatic glucose production,90 while the myokine FNDC5/irisin can rescue synaptic plasticity and memory function in mouse models of Alzheimer’s disease.91