leptin and Dwarfism

The US Food and Drug Administration approved use of recombinant human growth hormone (GH) for the treatment of idiopathic short stature (ISS) in children; however, few studies have evaluated metabolic outcomes. This article addresses whether children with ISS treated with GH experience the same metabolic benefits as children with GH deficiency (GHD) treated with GH. A systematic review of all published studies of GH treatment in children with ISS that included data on metabolic outcomes identified five studies. No meta-analysis has been performed.Studies show a metabolic response to GH treatment in children with ISS similar to that observed in children with GHD; effects include a transient decrease in insulin sensitivity and a dose-dependent increase in insulin-like growth factor I. However, no increase in the risk of diabetes was found. Children with ISS seem to benefit from GH treatment in terms of height gain without any severe negative metabolic outcomes.

Topics: Adipose Tissue; Adolescent; Body Height; Child; Dwarfism; Dwarfism, Pituitary; Glucose; Growth Disorders; Human Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Leptin; Lipid Metabolism; Male; Recombinant Proteins

Leptin levels may regulate fat metabolism, skeletal growth, and puberty. Leptin gene variants affect risk of obesity, cancer, but their effect on onset of growth hormone deficiency (GHD) and idiopathic short stature (ISS) is unknown. We tested the hypothesis that the phenotype of GHD and ISS may be associated with polymorphism in the leptin gene. The prevalence of a single nucleotide polymorphism (SNP) in the leptin gene (LEP) promoter at -2548 and the leptin and insulin growth factor-1 (IGF-1) concentrations in GHD and ISS were compared to those of healthy controls. IGF-1 and leptin concentrations were significantly lower in both the GHD and ISS groups than in the control group. The ISS and GHD groups had a significantly different distribution of SNP alleles at the LEP -2548 (P = 0.010). Individuals with LEP -2548A/G or G/G genotype in ISS group (47.5%) showed a significantly lower weight and body mass index (BMI) (but not leptin levels) than individuals carrying the A/A genotype (52.5%). LEP -2548A/A in GHD patients (65.8%) was associated with lower weight, BMI, leptin concentrations than those of individuals carrying the A/G or G/G genotype (34.2%). These data suggest that the LEP -2548A polymorphism may associate with the weight and BMI of the children with ISS and GHD.

Topics: Age Determination by Skeleton; Age Factors; Body Height; Body Mass Index; Body Weight; Child; Dwarfism; Female; Gene Frequency; Growth Disorders; Human Growth Hormone; Humans; Insulin-Like Growth Factor I; Leptin; Male; Polymorphism, Single Nucleotide

The extent to which childhood GHD affects adult fracture risk is unclear. We measured femoral strength in adult transgenic growth-retarded rats as a model of GHD. Long-term, moderate GHD was accompanied by endocrine and morphometric changes consistent with a significant reduction in femoral strength.. Childhood growth hormone deficiency (GHD) is associated with osteopenia, but little is known about its effects on subsequent adult bone strength and fracture risk.. We have therefore measured femoral strength (failure load measured by three-point bending) in a new model of moderate GHD, the transgenic growth-retarded (Tgr) rat at 15, 22-23, and 52 weeks of age, and have quantified potential morphological and endocrine determinants of bone strength.. Skeletal growth retardation in Tgr rats was accompanied by a sustained reduction in the anterior-posterior diameter of the femoral cortex, whereas mid-diaphyseal cortical wall thicknesses were largely unaltered. Total femoral strength was significantly impaired in Tgr rats (p < 0.01), and this impairment was more pronounced in males than females. Compromised bone strength in Tgr rats could not be accounted for by the reduction in mechanical load (body weight) and was not caused by impairment of the material properties of the calcified tissue (ultimate tensile stress), despite marked reductions in femoral mineral density (areal bone mineral density; p < 0.001). Microcomputerized tomographical analysis revealed significant modification of the architecture of trabecular bone in Tgr rats, with reductions in the number and thickness of trabeculae (p < 0.05) and in the degree of anisotropy (p < 0.01). The marked reduction in plasma insulin-like growth factor-1 in Tgr rats was accompanied by the development of high circulating leptin levels (p < 0.01).. These results show that the changes in endocrinology and bone morphology associated with long-term moderate GHD in Tgr rats are accompanied by changes consistent with a significant reduction in the threshold for femoral fracture.

Topics: Age Factors; Animals; Animals, Genetically Modified; Biomechanical Phenomena; Bone Density; Bone Development; Calcification, Physiologic; Compressive Strength; Dwarfism; Female; Femur; Growth Hormone; Insulin-Like Growth Factor I; Leptin; Male; Rats; Sex Characteristics; Weight Gain

Two molecular forms of human GH (hGH) have been shown to be biologically active. The 20 kDa form has been reported to have weaker diabetogenic and lipolytic actions than the 22 kDa form.. To analyze the carbohydrate metabolism of 20 kDa and 22 kDa hGH, using the adult male spontaneous dwarf rat (SDR), which is GH deficient.. SDRs were given 20 kDa or 22 kDa hGH in doses of 125 microg/rat or 500 microg/rat, or saline, for 10 days, and their weight, serum IGF-I, glucose, insulin, leptin and body composition were measured.. Weight and serum IGF-I increased both in the 20 kDa and 22 kDa groups, but IGF-I concentrations were significantly lower in the 20 kDa group than in the 22 kDa group. Serum glucose was not increased by either 20 kDa or 22 kDa hGH, whereas insulin was significantly increased after the higher dose of the 22 kDa hGH. Although blood concentrations of leptin were decreased by both 20 kDa and 22 kDa hGH, values were lower in the high-dose 20 kDa group than in the group given the same dose of 22 kDa hGH. Both forms of GH increased the percentage body water and body protein content, and decreased the percentage of body fat by the same degree. The observation that the higher dose of the 22 kDa hGH increased insulin concentrations without changing blood glucose demonstrates that this concentration of the hormone induces insulin resistance, whereas the same dose of 20 kDa hGH does not.. The results can be interpreted to indicate that the higher dose of the 22 kDa hGH has diabetogenic activity, as reported previously, whereas the 20 kDa hGH has lower diabetogenic activity. The 20 kDa form of hGH may therefore be more useful in treating adult GH deficiency, especially those with severe obesity.

Topics: Animals; Blood Glucose; Body Composition; Body Weight; Dwarfism; Human Growth Hormone; Insulin; Insulin-Like Growth Factor I; Leptin; Male; Molecular Weight; Rats; Rats, Sprague-Dawley