Galactosyl transferase activity in rat bladder transitional cell carcinoma lines and in exfoliated cells in urine during carcinogenesis and reversible hyperplasia.

Cultured cells of rat bladder transitional cell carcinoma line AY-27, in suspension, were assayed for galactosyl transferase (GT) by measurement of the transfer of [3H]galactose from uridine diphosphate-[3H]galactose to desialylated ovine submaxillary mucin (OSM-NANA). The assay was optimized with respect to time and to protein, uridine diphosphate galactose, OSM-NANA and Triton X-100 concentrations. This assay was then applied weekly to suspensions of exfoliated bladder cells collected from urines of rats fed the bladder carcinogen N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide, and of control rats. Increases in activity over controls appeared 42 weeks after feeding the carcinogen, at a stage when bladder tumors were already microinvasive or deeply invasive, and activities at 52 weeks were about 10-fold greater than normal values. In contrast, a bladder cytotoxic agent inducing reversible hyperplasia was injected into rats, and exfoliated cells were collected from urines: these cells showed no greater GT activity than normal. Bladder tumor tissue from a transplanted tumor had the same high specific enzymatic GT activity as exfoliated cells from tumor-bearing rats.