Endocrine Abstracts

JOINT3975

Introduction: Ghrelin is responsible for GH production and appetite stimulation. Ghrelin secretion is dependent on food intake, increases in the fasting state and decreases after meals. Ghrelin reduces energy expenditure and lipolysis and promotes weight gain. However, studies have shown that ghrelin levels are lower in obese individuals, whereas in leaner individuals they are higher than in controls. It seems that ghrelin may have a greater effect on postprandial satiety than on preprandial appetite stimulation. Some (but not all) small for gestational age (SGA) children who demonstrated catch-up phenomenon after birth, develop increasing obesity and elements of the metabolic syndrome. We therefore suspect an association between higher ghrelin levels and faster growth and weight gain in SGA children. The aim of the study was to assess fasting ghrelin levels and the degree of its reduction during oral glucose tolerance test (OGTT) in 5-9-year-old SGA children depending on BMI and the presence of metabolic syndrome components.

Material and Methods: 91 prepubertal SGA children (34 boys and 57 girls) aged 4. 78-9. 75 years (6. 9±1. 37 years) were qualified for the study. Height, body weight, waist circumference, and blood pressure were measured in each child. Fasting triglyceride and HDL-cholesterol levels were assessed. Glucose, insulin, and ghrelin levels were estimated fasting and during the (OGTT). Based on the obtained results, BMI SDS, waist-to-height ratio, and HOMA-IR were calculated.

Results: Ghrelin levels decreased significantly during OGTT [1859 (1356 – 3532) vs 1233 (953 – 1765), P = 0. 0000]. In obese children (BMI SDS>2), fasting ghrelin levels were significantly lower than in nonobese children [1491 (1179 – 2917) vs 2197 (1539 – 3874), P = 0. 0021], but decreased significantly more during the test [431 (163 -790) vs 693 (357 – 1798), P = 0. 0058]. There was no difference in fasting ghrelin levels and ghrelin decrease during OGTT between groups with respect to the presence of visceral obesity, high triglyceride levels, low HDL cholesterol levels or tendency to high blood pressure. We found weak, negative correlations between fasting ghrelin levels and: BMISDS (r = -0. 25), HOMA-IR (r = -0. 2), insulin levels at 0’ (r = -0. 21) and 120’ (r = -0. 24) of the OGTT; as well as between ghrelin levels at 120’ and insulin at 120’ (r = -0. 2).

Conclusion: Ghrelin levels in SGA children aged 5 to 9 years decreased significantly during OGTT, and this decrease was more profound in obese children. Further studies are needed to determine the impact of this finding on the improvement in growth rate and the development of metabolic disorders in SGA children.