Regulation of adipocyte leptin expression by signaling metabolite

Leptin is expressed in white adipocytes, but not in brown adipocytes. Circulating levels of leptin are determined by the endocrine activity of white adipose tissues. Leptin expression and secretion is regulated by hormones, neurotransmitters and triglyceride content in adipocytes. However, the role of metabolites remains largely unknown in leptin expression and secretion. This status has been broken by a recent study of succinate regulation of leptin secretion in adipocytes. As a mitochondrial metabolite, succinate level is elevated in the blood in obesity. The exact tissue source remains unknown for the elevated succinate, but succinate is able to activate its G protein-coupled receptor 1 (SUCNR1) in adipocytes to induce expression and secretion of leptin. Signaling pathway of the receptor is AMPK/JNK/C/EBP-α. Succinate is a representative of metabolites in the control of leptin expression.