Age-related decrease of urinary excretion of human epidermal growth factor (hEGF).

Epidermal growth factor (EGF) has been first isolated from the submandibular glands of the male mouse and recently from human urine. Despite its potent mitogenic effect in a variety of tissues, the physiological functions of EGF in human still remain undetermined. In order to study the effect of age on urinary human EGF (hEGF), we have evaluated urinary excretion of hEGF in normal subjects over a wide range of age (20-79 yr.) using homologous radioimmunoassay (RIA) for hEGF. Urinary excretion of hEGF expressed as a function of creatinine significantly decreased with increasing age, while females excreted significantly more hEGF than males. These data suggest that urinary excretion of hEGF decreases with age in normal subjects which may be due to reduced synthesis and/or secretion of hEGF.