Detailed studies... Article 1: Growth Hormone Treatment Article 2: Association Between Growth Factor and Bone Mineral Density Article 3: Growth Hormone (GH) Treatment Increase Isometric and Muscle Strength

  Study: Growth Hormone Treatment

Growth Hormone Treatment of Abdominally Obese Men Reduces Abdominal Fat Mass, Improves Glucose and Lipoprotein Metabolism, and Reduces Diastolic Blood Pressure

Gudmundur Johannsson, Per Mårin, Lars Lönn, Malin Ottosson, Kaj Stenlöf, Per Björntorp, Lars Sjöström and Bengt-Åke Bengtsson

STRIKING similarities exist between the metabolic syndrome (also labeled syndrome X or primary insulin resistance syndrome) and untreated GH deficiency in adults.

The most central findings in both these syndromes are abdominal/visceral obesity and insulin resistance.

Other features common to both conditions are high triglyceride (TG) and low high-density lipoprotein cholesterol concentrations, an increased prevalence of hypertension, elevated levels of plasma fibrinogen and plasminogen activator inhibitor (PAI)-1 activity, premature atherosclerosis, and increased mortality from cardiovascular diseases.

The metabolic syndrome is associated with multiple endocrine abnormalities. They include increased cortisol secretion, blunted secretion of gonadotrophins and sex steroids, and abnormalities in the GH/insulin-like growth factor I (IGF-I) axis.

With increased adiposity, GH secretion is blunted with a decrease in the mass of GH secreted per burst but without any major impact on GH secretory burst frequency. The serum IGF-I concentration is primarily GH dependent and influences GH secretion through a negative feedback system.

The serum levels of IGF-I are inversely related to the percentage of body fat (BF). In addition, we have shown previously that the low serum IGF-I concentration in obesity is predominantly related to the amount of visceral adipose tissue and not to the amount of sc fat mass.

These findings, together with other endocrine disturbances in central obesity, suggest that the low GH secretion that is observed is secondary to a central disturbance of the neuroendocrine regulation, including the GH/IGF-I axis.

Replacement therapy with recombinant human GH (rhGH) has demonstrated favorable effects on most of the features of GH deficiency in adults.

Whether rhGH treatment can improve the metabolic abnormalities observed in abdominal/visceral obesity has never been investigated.

In the present study, a randomized, double-blind, placebo-controlled design was used to evaluate the effects of 9 months of rhGH administration in patients with abdominal/visceral obesity.