Serum Levels of 20-Kilodalton Human Growth Hormone (GH) in Children with Simple Obesity

摘要

Twenty-kilodalton human GH, a human GH (hGH) variant, has insulin-like and anti-insulin-like actions different from 22-kilodalton hGH (22K). The diabetogenic action of twenty-kilodalton hGH (20K) is reported to be weaker than that of 22K, yet it is still unclear whether secretion of 20K is influenced by factors in carbohydrate metabolism. We measured serum 20K and 22K in children with simple obesity and studied the regulation of 20K production. The subject were 124 boys (9.78 ± 1.94 yr old, body mass index (BMI) 25.88 ± 2.43 kg/m2) and 54 girls (10.29 ± 2.25 yr old, BMI 26.90 ± 3.72 kg/m2) with simple obesity. The serum samples were taken after overnight fasting. The data was compared with the data from children with non-GH deficient (GHD) short stature. The mean serum concentrations of 22K and 20K were 1.47 ± 1.63 ng/ml and 81.3 ± 80.3 pg/ml in obese boys and 1.86 ± 2.00 ng/ml and 108.9 ± 120.4 pg/ml in obese girls. The percentage of 20K in hGH was 7.4 ± 5.0% in obese boys and 6.5 ± 2.9% in obese girls, and the percentage was not significantly different from the percentage of 20K in children with non-GHD short stature. The height SD score, obesity index, body fat mass, BMI, fasting blood sugar, insulin, homeostasis model assessment-R (HOMA-R), HbA1c, total cholesterol, triglyceride, leptin and IGFBP-1 were not correlated to the percentage of 20K. We conclude that the percentage of 20K is constant not only in normal children but also in obese children, and factors that correlate with obesity such as glucose and insulin do not influence the 20K splicing mechanism.