The Effects of Diet and Chronic Exercise on Skeletal Muscle Ghrelin Response

Abstract

Ghrelin is an orexigenic hormone that was initially believed to only play a role in appetite regulation. Recently ghrelin has been shown to stimulate fatty acid oxidation and preserve insulin response in muscle in conditions of elevated fatty acid availability. These effects are lost following chronic high-fat feeding in skeletal muscle. Whether ghrelin’s peripheral effects are altered with exercise has not been examined. We found that ghrelin response was present in skeletal muscle following 5 days of high, or low-fat feeding, but lost following 6 weeks of a high-fat diet. Exercise was able recover ghrelin mediated increases in fatty acid oxidation and the preservation of insulin stimulated glucose uptake. The preservation of ghrelin response was accompanied by increases in CRF-2R content, the purported receptor for UnAG in skeletal muscle. These findings suggest that exercise is able to prevent the development of skeletal muscle ghrelin resistance in high-fat fed rats.