Effects of growth hormone and/or testosterone on very low density lipoprotein apolipoprotein B100 kinetics and plasma lipids in healthy elderly men: A randomised controlled trial

ObjectiveTo assess the effects of low dose recombinant growth hormone (GH), testosterone (T) and combined GH and T, on lipid profiles and very low density lipoprotein apolipoprotein B (VLDL apoB) metabolism.Design and patientsSixty-nine healthy elderly men (65–80 yr) were studied in a six month double-blind, placebo-controlled trial. Participants were randomised to placebo GH and placebo T (P), GH and placebo T (GH), T and placebo GH (T) or GH and T (GHT).MeasurementsPlasma lipid profiles were assessed before treatment and at 6 months. VLDL apoB absolute secretion rate (ASR) and fractional catabolic rate (FCR) were measured in a subset of 21 men: P (n = 5); GH (n = 5); T (n = 6); GHT (n = 5), with an infusion of 1-13C leucine. Fat mass (FM) was measured by DEXA and intra-abdominal fat (IAF) by CT scan.ResultsIGF-I levels increased in the GH and GHT (P < 0.001) groups: testosterone increased in the T (P = 0.029) and GHT (P = 0.05) groups. There was no change in total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, apolipoprotein A-I, apolipoprotein B or lipoprotein(a) in the GH, GHT or T groups. In the subset of 21 men, IGF-I levels increased similarly with GH and GHT (P < 0.01) but T levels increased only with T (P < 0.03). FM and IAF decreased significantly only with GHT (P < 0.01, P = 0.01). Treatment with GH, T or GHT had no effect on VLDL apoB ASR or VLDL FCR.ConclusionCo-administration of GH and T in near physiological doses in healthy elderly men resulted in favourable changes in body composition without altering the plasma lipid profile or VLDL apoB metabolism.