Insulinotropic activity in the serum of obese and nonobese infants and children
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Insights
A specific serum fraction stimulates insulin release in obese children, potentially playing a role in obesity development. This islet-stimulating activity was linked to obesity severity and growth rate in children.
Area of Science:
- Pediatrics
- Endocrinology
- Metabolic Research
Background:
- Obesity in children is a growing concern with complex etiologies.
- Insulin regulation is crucial in metabolic health and obesity.
- The role of serum factors in pediatric obesity is not fully understood.
Purpose of the Study:
- To investigate the presence and characteristics of a serum fraction that stimulates insulin release in vitro.
- To determine the correlation of this activity with obesity and growth parameters in children.
Main Methods:
- Sera from 123 obese and normal-weight children (0-17 years) were fractionated by molecular filtration after urea treatment.
- Insulin release was measured using a bioassay with isolated rat islets in perifusion.
- High-performance liquid chromatography was used to analyze the molecular characteristics of the active fraction.
Main Results:
- An islet-stimulating activity was detected in serum fractions (mol wt 1000-5000) of obese children, particularly those under 10 years.
- This activity was also present in infants but infrequent in older normal-weight children.
- The activity positively correlated with obesity duration, degree, and linear growth rate, sharing elution characteristics with hypothalamic insulin-glucagon liberin.
Conclusions:
- A serum islet-stimulating factor is present in children and associated with obesity.
- This factor may play a role in the pathogenesis of childhood obesity.
- Further research is needed to elucidate the molecular structure and origin of this insulinogenic activity.
Abstract:
The ability of a serum fraction, mol wt 1000-5000, to stimulate insulin release in vitro was studied in 123 obese and normal weight children aged 0-17 yr. The sera were fractionated by serial molecular filtration after treatment with urea. Stimulation of insulin release was determined with a bioassay using isolated rat islets in perifusion. The islet-stimulating activity was found in all obese children less than the age of 10 yr and in the majority of the obese children older than 10 yr of age. In normal weight children the activity was also found in the majority of infants, but was infrequent in older children. The serum islet-stimulating activity was positively correlated with the duration and degree of obesity and with linear growth rate. The molecular structure and origin of the insulinogenic activity in the serum is still unknown. In high-performance liquid chromatography it has the same elution characteristics as the hypothalamic insulin-glucagon liberin. The present results suggest a role for the serum islet-stimulating activity in the pathogenesis of obesity.