GLYCOPROTEINS IN THE UROTHELIUM AND IN THE URINE OF THE EPIDERMAL GROWTH-FACTOR INDUCED GROWING URINARY-TRACT IN RATS

Systemic treatment with epidermal growth factor (EGF) induces growth o f all wall layers of the urinary tract in pigs and rats. We have previ ously described that the EGF stimulated urothelium in Goettingen minip igs accumulates glycoproteins. The aim of the present study was to exa mine and partly characterize glycoproteins in the urothelium and in th e urine from rats treated with EGF. Seventy-two female Wistar rats wer e allocated into five groups receiving EGF treatment (150 mu g/kg per day) for 0 (controls), 1, 2, 3 and 4 weeks before being killed. Glycoc onjugates were characterized by means of lectins on tissue sections, a nd using Western blotting, in bladder extracts and in urine. The chara cterization mostly focused on the expression of the mucin-type core st ructures T and Tn using the lectins peanut agglutinin (PNA) and Vicia villosa (VVA) and specific monoclonal antibodies. The thickened EGF-st imulated urothelium retained the normal differentiation pattern as jud ged from the appearance on electron microscopy and from the expression of carbohydrate structures. Within the urothelium and in the urine th ere was increased expression of mucin-type glycoproteins suggesting in creased urothelial production and excretion of mucin-type glycoprotein s. In conclusion, the EGF stimulated hyperplastic urothelium most prob ably excretes increased amounts of mucin-type glycoproteins to the uri ne but it retains the normal pattern of differentiation as assessed by lectin characterization.