from The Scientist News & Opinion
Excerpt: “This shows that there is some molecular evidence to support that notion that exercise is a medicine,” Zierath added.
The common molecular biology across vertebrate species suggests that the epigenetic effects either of movement, or of exercise, on gene expression is due to the same mechanisms I have detailed in the context of the gene, cell, tissue, organ, organ system pathway (in accord with the FDA Critical Path Initiative and ASAM policy statement on addiction). This pathway links sensory input from the environment directly to gene activation and behavior. In mammals, for example, it is the gonadotropin releasing hormone (GnRH) neuronal system that is primarily responsible for the epigenetic effects of nutrient chemicals and species-specific pheromones on intracellular signaling and stochastic gene expression in brain tissue responsible for movement. See for example: Feedback loops link odor and pheromone signaling with reproduction. Boehm U, Zou Z, Buck LB. Cell. 2005 Nov 18;123(4):683-95.
There is no reason not to link this common pathway to epigenetic effects of exercise on muscle tissue, because the hypothalamic GnRH pulse modulates pituitary secretion of gonadotropins involved in steroidogenesis and neurotransmission. Of particular interest is the effect of food odors and pheromones on hippocampal neurogenesis, thereby linking neurotransmission to learning, and memory that is also linked to the secretion of luteinizing hormone (LH). This links 1) the requirement for movement involved in food acquisition; 2) the requirement for movement involved in mate selection; and 3) the requirement for movement and/or exercise involved in reproductive fitness to survival of individuals and to species survival in species from microbes to man.
The model is the same for the development of species specific behaviors that depend on proper nutrition and nutrient metabolism to species specific pheromones. For example, in mammals: LH is the link between sex and the sense of smell (at least until someone suggests another model based on the basic principles of biology and levels of biological organization that are required).