Metabolic Association between Leptin and the Corticotropin Releasing Hormone

Abstract

Objective: In healthy individuals, leptin is produced from adipose tissue and is secreted into the circulation to communicate energy balance status to the brain and control fat metabolism. Corticotropin- Releasing Hormone (CRH) is synthesized in the hypothalamus and regulates stress responses. Among the many adipokines and hormones that control fat metabolism, leptin and CRH both curb appetite and inhibit food intake. Despite numerous reports on leptin and CRH properties and function, little has been actually shown about their association in the adipose tissue environment.

Methods: In this article, we summarized the salient information on leptin and CRH in relation to metabolism. We also investigated the direct effect of recombinant CRH on leptin secretion by primary cultures of human adipocytes isolated from subcutaneous abdominal adipose tissue of 7 healthy children and adolescents, and measured CRH and leptin levels in plasma collected from peripheral blood of 24 healthy children and adolescents to assess whether a correlation exists between CRH and leptin levels in the periphery.

Results and conclusion: The available data indicate that CRH exerts a role in the regulation of leptin in human adipocytes. We show that CRH downregulates leptin production by mature adipocytes and that a strong negative correlation exists between CRH and leptin levels in the periphery, and suggest the possible mechanisms of CRH control of leptin. Delineation of CRH control of leptin production by adipocytes may explain unknown pathogenic mechanisms linking stress and metabolism.

Keywords: Leptin; adipocytes; corticotropin-releasing hormone (CRH); expression; metabolism; signaling; stress..