CHRONIC SYSTEMIC TREATMENT WITH EPIDERMAL GROWTH-FACTOR IN PIGS CAUSES PRONOUNCED UROTHELIAL GROWTH WITH ACCUMULATION OF GLYCOCONJUGATES

Epidermal growth factor (EGF) is present in large amounts in the urine , but the effects of systemically administered EGF on the urinary trac t have not been described previously. In the present paper, we describ e a potent growth induction of EGF on the urinary solvent (n = 5), EGF 30 mu g/kg/day for 5 weeks followed by 3 weeks of recovery (n = 5). t he ureters and bladders were examined by routine histology and electro n microscopy and were immunostained for proliferating cell nuclear ant igen. Four weeks of EGF treatment increased the median cross sectional area of the ureter fourfold with growth of all wall layers. The uroth elium was widened from 5 cell layers in the controls to 10 in the EGF- treated animals. Proliferating cell nuclear antigen immunostaining rev ealed an increased mitotic activity in the basal zone of the urotheliu m. In the luminal zone, glycoconjugates accumulated in goblet cells, i n cells with intracytoplasmic lumina, and beneath the luminal cell mem brane in the umbrella cells. Our studies present a new experimental ap proach to growth induction of the urinary tract. The findings implicat e the EGF system in regulating urothelial growth and glycoconjugate bi osynthesis.