Classic and Novel Sex Hormone Binding Globulin Effects on the Cardiovascular System in Men

Figure 2

Hypothetical pathways leading to SHBG expression and their modulation in the heart. A hypothetical intracellular pathway for SHBG expression in the cardiomyocytes. The same membrane receptors modulating SHBG expression in the liver could be expressed in the heart. Metabolic cues modulate the activity of the transcription factor hepatocyte nuclear factor 4-α (HNF4α), which leads to an increase in SHBG gene expression. The following are some of the questions that arise relating to the possible production and secretion of SHBG as an endocrine or paracrine mediator: (1) Can TNFα, IL-1β, and adiponectin modulate SHBG expression in cardiac tissue? (2) Is the heart involved in the release of soluble SHBG in a paracrine or endocrine way? (3) Can soluble SHBG trigger intracellular signaling pathways in the heart?