IGF-I is an insulin-like peptide synthesized by liver and is a key control point for nutritional regulation of growth. Leptin is a protein hormone synthesized by adipose tissue, that play a role in metabolism and growth. IGF-I and leptin has been found in human milk otherwise their presence in milk-formula has not been detected. Growth and body composition differences between breast (BF) and formula-fed (FF) infants are at the moment not completely understood. Animal studies suggest that eccessive protein intake could results in increased IGF—I levels, but data on infants are not available. The aim of the present study was to evaluate the correlation between IGF—I and leptin in infants in the first months of life according to the kind of feeding (exclusively BF or FF); 21 AGA healthy infants, exclusively BF, and 29 infants FF were evaluated at an average age of 6 months. Serum IGF-I concentration was determinated on venous blood samples at least 3 h postfeeding, by chemiluminescence (kit Nichols Advantage, USA), leptin was evaluated by a radioimmunoassay RIA (LEP-R44 Mediagnostic, Germany). We found in FF infants, in the first 4 months of life, higher values of IGF-I (39.34 ng/ml) than BF infants (24.59 ng/ml) (p<0.05), differently leptin was founf higher in BF infants. The increased IGF-I levels observed in FF infants might be primarily caused by an higher protein intake, and this could increase the risk of obesity later in life.
Serum insulin-like growth factor-i and leptin in infants in the first months of life
OGGERO, Roberto;SILVESTRO, Leandra;
2003-01-01
Abstract
IGF-I is an insulin-like peptide synthesized by liver and is a key control point for nutritional regulation of growth. Leptin is a protein hormone synthesized by adipose tissue, that play a role in metabolism and growth. IGF-I and leptin has been found in human milk otherwise their presence in milk-formula has not been detected. Growth and body composition differences between breast (BF) and formula-fed (FF) infants are at the moment not completely understood. Animal studies suggest that eccessive protein intake could results in increased IGF—I levels, but data on infants are not available. The aim of the present study was to evaluate the correlation between IGF—I and leptin in infants in the first months of life according to the kind of feeding (exclusively BF or FF); 21 AGA healthy infants, exclusively BF, and 29 infants FF were evaluated at an average age of 6 months. Serum IGF-I concentration was determinated on venous blood samples at least 3 h postfeeding, by chemiluminescence (kit Nichols Advantage, USA), leptin was evaluated by a radioimmunoassay RIA (LEP-R44 Mediagnostic, Germany). We found in FF infants, in the first 4 months of life, higher values of IGF-I (39.34 ng/ml) than BF infants (24.59 ng/ml) (p<0.05), differently leptin was founf higher in BF infants. The increased IGF-I levels observed in FF infants might be primarily caused by an higher protein intake, and this could increase the risk of obesity later in life.
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