Text Box: INSULIN-LIKE GROWTH FACTORS (IGF-I, IGF-II) CONCENTRATION IN CORD BLOOD OF PRETERM NEONATES Walczak M1, Fydryk J1, Korman E3, Ciechanowska B1, Giżewska M1, Pankiewicz E2 1Department of Pediatrics and 2 Department of Neonatology, Pomeranian Academy of Medicine, Szczecin, Poland 3 Department of Pediatric Endocrinology and Diabetes, University of Medicine Sciences, Poznań, Poland Objective: Insulin-like growth factors stimulate cellular proliferation. Some data suggest that their concentrations immediately after birth are related to newborn’s maturity. The aim of study was to assess relationship between concentration of insulin-like growth factors in cord blood and newborn’s maturity at the time of delivery. Methods: 99 newborns were included into the study group, 48 born prematurely (x= 33.8±SD 2.2 wk.; 2126.7±549.9 g) and 51 born at term (x=39.1±1,4 wk.; 3365.7±462.4g), both groups were appropriate for gestational age. Concentrations of insulin-like growth factors were measured in serum of cord blood, taken immediately after birth. Concentrations of IGF-I and IGF-II were measured by radioimmunoassay (RIA) method using Medgenix (Belgium) and DSL (USA) isotopes, respectively. Results: Statistically significant higher concentrations of insulin-like growth factors were found in neonates born at term. The difference in concentration of IGF-II (x=50.8±SE 2.3 nmol/l vs. 38.8±1.9 nmol/l; p<0.001) was more significant than of IGF-I (x= 11.8±0.7 nmol/l vs. 10.9±0.9 nmol/l; p<0.05). Contrary to IGF-I, significant correlation of IGF-II concentration and newborn’s maturity was observed (r=0.3616; p<0.01). Conclusions: Synthesis and/or excretion of insulin-like growth factors increase with duration of pregnancy. Higher differences in concentrations of IGF-II in born at term and preterm neonates indicate that the increase of synthesis and/or excretion of IGF-I to fetal circulation takes place earlier in life than IGF-II. 2489