Effects of growth hormone (GH) replacement therapy on very low density lipoprotein apolipoprotein B100 kinetics in patients with adult GH deficiency: a stable isotope study

Patients with adult GH deficiency are often dyslipidemic and may have an increased risk of cardiovascular disease. The secretion and clearance of very low density lipoprotein apolipoprotein B 100 (VLDL apoB) are important determinants of plasma lipid concentrations. This study examined the effect of GH replacement therapy on VLDL apoB metabolism using a stable isotope turnover technique. VLDL apoB kinetics were determined in 14 adult patients with GH deficiency before and after 3 months GH or placebo treatment in a randomized double blind, placebo-controlled study using a primed constant[ 1-13C]leucine infusion. VLDL apoB enrichment was determined by gas chromatography-mass spectrometry. GH replacement therapy increased plasma insulin-like growth factor I concentrations 2.9 ± 0.5-fold (P < 0.001), fasting insulin concentrations 1.8 ± 0.6-fold (P < 0.04), and hemoglobin A1C from 5.0 ± 0.2% to 5.3 ± 0.2% (mean ± sem; P < 0.001). It decreased fat mass by 3.4 ± 1.3 kg (P < 0.05) and increased lean body mass b...