Leptin concentrations in GH deficiency: the effect of GH insensitivity

Area of Science:

• Endocrinology
• Metabolic Disorders
• Genetics

Background:

• Growth hormone (GH) secretion disorders impact physiological lipostat and leptin secretion, a marker of body composition and fat accumulation.
• Growth hormone deficiency (GHD) and growth hormone insensitivity (GHI) are associated with increased adiposity and altered lipid profiles.
• Leptin levels are elevated in GHD and GHI patients, correlating with increased adiposity.

Purpose of the Study:

• To investigate the impact of different forms of growth disorders, specifically GHI and GHD, on leptin production.
• To compare leptin levels in patients with homozygous GHI, heterozygous GHI, idiopathic GHD, and normal controls.
• To assess the effect of short-term GH therapy on leptin, IGF-I, and IGFBP-3 levels in these groups.

Main Methods:

• Leptin, IGF-I, and IGFBP-3 levels were measured in 22 homozygous GHI, 20 heterozygous GHI, 17 idiopathic GHD patients, and 44 normal subjects.
• Subjects underwent two 7-day GH treatments at different doses.
• Specific immunoassays were used for all measurements; multivariate analysis was employed to identify predictors of leptin levels.

Main Results:

• Homozygous GHI patients exhibited significantly higher leptin levels compared to normal controls, heterozygous GHI subjects, and GHD patients.
• Leptin levels were significantly higher in GHI females and GHD males compared to their respective controls.
• GH therapy did not significantly alter leptin levels in any of the study groups, although IGF-I and IGFBP-3 levels increased.

Conclusions:

• Elevated leptin levels in homozygous GHI patients likely reflect underlying abnormalities in body composition and metabolism.
• Leptin levels are influenced by gender and body mass index in homozygous GHI patients and normal individuals.
• Short-term GH administration does not acutely affect leptin levels in patients with GHI or GHD.