Renal bile acid excretion as a cause of neoplastic lesions in the urinary tract after total portacaval shunt in the normal rat?

Rats with a total portacaval anastomosis (PCA, PC-SS) develop preneoplastic and neoplastic lesions in the urinary tract. In contrast to this, animals with a modified shunt (mPCA) do not develop these lesions. To evaluate the possible role of bile acids excreted with the urine for tumor development, total plasma bile acid concentration and 24 hours urinary bile acid excretion were measured radioimmunologically in rats with total and modified shunts. Additionally the renal 14C-glycocholic acid excretion into the urine was studied after oral administration. Total plasma BA increased from 4.89 +/- 1.0 mumol/l in sham-operated controls to 77.7 +/- 39 mumol/h in PCA and 52.9 +/- 36.7 mumol/l in mPCA rats (p less than 0.001 vs controls, PCA vs mPCA = n.s.). Urinary bile acid excretion rose from 0.2 +/- 0.29 mumol/24 hours in controls to 4.47 +/- 4.49 in PCA and 2.55 +/- 2.22 mumol/24 hours in mPCA rats (p less than 0.001 vs control; PCA vs mPCA = n.s.) 14C-glycocholic acid was excreted within 24 hours into the urine in 13.6 +/- 11.5% in PCA and 26.3 +/- 23.5% of the administered dose in mPCA-rats (controls; 2.98 +/- 0.67%, p less than 0.001; PCA vs mPCA = n.s.). Since renal BA-excretion is similar in both shunted groups, urinary BA does not seem to be of primary significance for cancer development in the urinary tract of totally shunted rats.