ABOVE: FLICKR, JOSIAH MACKENZIE
Despite reports questioning the role of the hormone irisin (and indeed, its very existence), Harvard Medical School’s Bruce Spiegelman and his colleagues today (August 13) provide fresh evidence substantiating the protein’s function in physical activity. The results of the team’s latest irisin analysis appeared today (August 13) in Cell Metabolism.
Spiegelman’s group first identified irisin as a hormone released from human muscle during physical activity in 2012. It has been a source of scientific contention ever since.
Three years ago, Spiegelman’s team showed that the type I transmembrane protein FNDC5 is upregulated in muscle during exercise in both mice and humans. The researchers had also reported that, during physical activity, the protein’s extracellular portion—which they called irisin—is cleaved and released into the blood stream.
This March, a team led by investigators at Germany’s Leibniz Institute for Farm Animal Biology questioned the quality of the antibody used ...
