As one’s muscle contracts during exercise, it
induces cytokine interleukin-6 (IL-6) gene expression
locally in contracting skeletal muscles. Likewise, an
exercising limb releases high amounts of IL-6 into the
blood. In fact, IL-6 levels increase dramatically
(≤100-fold) in response to exercise [7].
The IL-6 that is produced passes through the
bloodstream and eventually binds to its receptor on
hepatocytes.
IL-6 binding induces the LDLR gene by acting on its
promoter site; thus, further enhancing the binding of
nuclear proteins to their cognate DNA sequence of the LDLR
promoter (not shown). In turn, stimulating LDLR
transcription [9].
Consequently, the LDLR activity on the surface of
liver cells is enhanced, leading to an increased uptake of
LDL from the circulation [9].
