Schematic representation of the proposed mechanism underlying 4-HNE-induced enhancement of lipolytic response in adipocytes.

<p>4-HNE-triggered lipolysis in adipocytes involves the activation of the cAMP/PKA/HSL pathway as well as the suppression of the AMPK pathway. Both AC activation and PDE3B inhibition potentially contribute to 4-HNE-induced increase of intracellular cAMP levels. PKA, protein kinase A; HSL, hormone-sensitive lipase; AMPK, AMP-activated protein kinase; P, phosphorylation; TG, triglyceride; FFA, free fatty acids; AC, adenylyl cyclase; PDE3B, phosphodiesterase 3B; ? hypothetic mechanism.