Leptin, IGF-I and Insulin Concentrations in Children with Malnutrition-Related Short Stature Due to Poor Appetite

Park, Mi Jung

Abstract

PURPOSE: Among children who visited hospital because of short stature, malnutrition-related short stature(MRSS) is often observed. Most of these children showed significantly decreased appetite without medical cause. Leptin is a very important weight regulating protein through a feedback signal between adipose tissue and the satiety center. IGF-I and insulin are also very important weight regulating hormones with adipogenic and somatotropic effects. Therefore, we have undertaken this study to examine the levels of leptin, IGF-I and insulin in MRSS and to analyze the relationship among these growth factors.
METHODS
Twenty children more than 5 years old, who visited Sanggye Paik Hospital due to poor growth were enrolled. Their weight and height are less than 10 percentile of the Korean weight standard curve. All subjects had no organic disorders and their growth hormone levels were normal. Twenty healthy children whose height and weight were between the 25-75 percentiles were enrolled as a control group. The serum levels of leptin, IGF-I and insulin were measured by RIA method.
RESULTS
1)Leptin concentration was significantly lower in the MRSS than in the control group(2.35+/-1.05 vs 3.20+/-2.31 ng/mL, P<0.05, Fig. 1). 2)IGF-I concentration was significantly lower in the MRSS than in the control group(176.4+/-93.1 vs 258.2+/-221.3 ng/mL, P<0.05, Fig. 2). 3)Insulin concentration was lower in the MRSS than in the control group but showed no significant differences(17.9+/-13.9 vs 21.8+/-14.0 microIU/mL, Fig. 3). 4)Leptin was positively correlated with body weight(r=0.49, P<0.05) and BMI (r=0.55, P=0.01) in the control group, but was not correlated in the MRSS group. 5)IGF-I was positively correlated with body weight(r=0.61, P<0.05) and height (r=0.56, P<0.05) and BMI(r=0.50, P=0.05) in the control group, but was not correlated in the MRSS group. 6)There were no correlations among leptin, IGF-I and insulin both in the control and MRSS group.
CONCLUSION
We speculate that low leptin and IGF-I concentrations in MRSS group might be related to the result of a poor nutritional state and might be an adaptive mechanism to reduce energy expenditure to increase appetite. To elucidate the underlying mechanism of poor appetite and adaptational changes of leptin, IGF-I and insulin, further studies with more cases are needed.