Human urinary epidermal growth factor excretion: age, sex, and race dependence

We measured the urinary excretion of immunoreactive epidermal growth factor (IR-EGF) in random urine specimens obtained from 358 ambulatory patients and normal subjects, aged 18-90 yr, with a homologous EGF RIA. We also measured IR-EGF excretion in 24-h urine collections from 40 additional normal subjects, aged either 20-29 or 60-69 yr, to detect possible artifacts introduced in the analysis of random urine specimens by the age-related decline in the glomerular filtration rate. Urinary IR-EGF excretion decreased in a linear fashion with increasing age. Women excreted more IR-EGF than men, and whites excreted more IR-EGF than blacks of the same age and sex, but the rate of decline with increasing age was similar for all groups. These findings may provide additional insight into the role of EGF in human renal physiology.