Exp Clin Endocrinol Diabetes 2005; 113 - 4
DOI: 10.1055/s-2005-862863

Metabolic effects of intravenous corticotropin releasing hormone on adipose tissue metabolism in humans

P Wellhöner 1, M Welzel 1, D Rolle 1, HL Fehm 1, C Dodt 1
  • 1UKSH-Campus Lübeck, Med Klinik I, Lübeck

Introduction: Apart from its well known function in the central nervous system corticotropin releasing hormone (CRH) seems to have an additional role in peripheral tissues. Besides in the myocardium and skin, CRH receptors (CRH-R) have also been found in human adipose tissue and intravenous administration of CRH in humans leads to an increase of energy expenditure and fatty acid oxidation. In order to further clarify the role of CRH in adipose tissue we investigated changes in adipose tissue metabolites and blood flow after injection of CRH in humans.

Material and Methods: 12 male, healthy volunteers were treated intravenously with either 100ug CRH or placebo in a randomized, double blind, crossover experiment. Changes in interstitial glycerol, lactate, pyruvate and glucose were monitored with microdialysis in femoral adipose tissue (flow rate 5ul/min, 5min sampling interval). Adipose tissue blood flow (ATBF) was continuously registered using laser Doppler flowmetry. Blood samples for the determination of ACTH, and cortisol were drawn regularly to verify the effect of CRH on the HPA axis. Statistical analysis of the effects of time and treatment on adipose tissue metabolites and blood flow relied on ANOVA with repeated measures.

Results: As expected i.v. CRH caused a time dependent increase in serum cortisol and ACTH with its maximum peak after 45min. Concentrations for interstitial glycerol, lactate and glucose increased shortly after CRH injection reaching a maximum after 15 minutes (p<0.0001). There was no corresponding change in ATBF after i.v. CRH.

Conclusions: Intravenous CRH has immediate lipolytic effects on femoral subcutaneous adipose tissue in vivo which is reflected by an increase of interstitial adipose tissue glycerol. This early increase cannot be attributed to changes in serum ACTH or cortisol and is not caused by an alteration in adipose tissue blood flow. From this data we conclude that i.v. CRH directly stimulates lipolysis in vivo.