Age-related changes of serum progastrin-releasing peptide levels during childhood.

Gastrin-releasing peptide (GRP) has attracted much attention in recent years because it has become recognized as a significant tissue-specific growth factor. To investigate the physiological significance of this peptide in growing children, the time course of serum ProGRP(31-98) level, a precursor hormone of GRP, in children was assessed. A total of 118 serum samples including cord blood was examined with informed consent by using a specific enzyme-linked immunosorbent assay (ELISA) system to measure serum ProGRP(31-98). The serum ProGRP(31-98) level was highest in cord blood and neonatal samples, rapidly declined by 1 year of age and then gradually declined to the adult level by 5 years of age. This time-dependent change of serum ProGRP(31-98) level suggests the importance of GRP as a physiological growth factor in fetal and neonatal tissues.