Short-Term Effects of Growth Hormone on Lipolysis, Glucose and Amino Acid Metabolism Assessed in Serum and Microdialysate of Healthy Young Men.

Abstract

OBJECTIVE\nWe investigated direct effects of a therapeutic growth hormone dose on lipolysis, glucose and amino acid metabolism.\n\n\nMETHODS\nThis crossover microdialysis trial involved six healthy male volunteers receiving single subcutaneous injections of both growth hormone (0.035\u2009mg/kg) and placebo (0.9% sodium chloride). The investigation comprised three test days with standard diet. The first day served for adaptation, the second and third one for determining study data during 9 night hours with or without growth hormone. Abdominal subcutaneous microdialysate and blood were continuously collected and forwarded to a separate room next door where hourly taken samples were centrifuged and frozen until analysed.\n\n\nRESULTS\nGrowth hormone achieved the peak serum level after 3\u2009h followed by a plateau-like course for the next 6\u2009h. Glycerol in microdialysate started to rise 2\u2009h following growth hormone injection achieving significance compared to placebo after 9\u2009h (P<0.05). Serum glycerol increased 4\u2009h after growth hormone administration achieving significance after 6\u2009h (P<0.05). Glucose and amino acid concentrations showed neither in microdialysate nor in serum significant differences between growth hormone and placebo. Serum values of insulin and C-peptide revealed no significant difference between growth hormone and placebo.\n\n\nSUMMARY AND CONCLUSION\nAs the result of a high single subcutaneous dose of GH, persistent lipolysis can be shown in continuously collected microdialysate and blood, but no indication for gluconeogenesis or protein anabolism.