Background: Altered hepatic mitochondrial activity plays a key role in the development of non-alcoholic fatty liver disease (NAFLD). GH has been shown to stimulate mitochondrial function in skeletal muscle. Therefore we hypothesize that the time course of serum GH concentrations during an oral glucose tolerance test might be related to hepatic mitochondrial energy metabolism in vivo in humans.
Methods: 15 volunteers (male/female: 7/8; 55±8 years; BMI 25±4 kg/m2) were investigated on two study days; i) oral glucose tolerance tests were performed to assess dynamics of glucose, insulin, C-peptide and GH concentrations and ii) hepatic lipid content was measured by 1H/31P magnetic resonance spectroscopy (MRS). Saturation transfer technique was applied to assess ATP synthesis rate (k).
Results: Basal GH concentrations and GH dynamics strongly correlated with hepatic mitochondrial activity (GHbaseline&kliver:r=0.783; P<0.001; GHAUC& kliver: r=0.676; P=0.008). There was no association between HCL and GH, as well as between HCL and kliver. Six subjects fulfilled criteria for NAFLD (HCL≥5.5%). They presented significantly higher glucose levels and insulin resistance. The strong relationship between GH and kliver did not differ between patients with and without NAFLD.
Discussion: Our data indicate that basal as well as postprandial (oGTT) GH concentrations are directly related to hepatic energy metabolism in insulin sensitive and insulin resistant humans.
20 - 23 May 2017
European Society of Endocrinology