We have previously reported the preparation of
monoclonal antibodies specific for
antigens localized in the rat renal papilla. Three of the
monoclonal antibodies reacting with
antigens localized in papillary and cortical collecting duct epithelia were selected for the development of
enzyme-linked
immunosorbent assay (ELISA)-type assays. The papillary
antigens ('PapA') determined in these tests were designated PapAl (applying the
monoclonal antibody PapX 5C10),
PapA2 (applying the
monoclonal antibody PapX 12F6), and PapA3 (applying the
monoclonal antibody PapXI 3C7). Using these assays
antigen excretion was determined in the urine of rats. Depending on the test compound used. the application route, and the dose, the observed
antigen release patterns differed. Whereas after a single intraperitoneal application of
2-bromoethanamine or of
propyleneimine an increased release of PapA1 but not of the two other
antigens was observed oral application of bromoethanamine had minor effects. In contrast, both a single intraperitoneal application or repeated oral applications of
indomethacin resulted in an increased release of all the three
antigens. Daily application of
ipsapirone in the diet or in
drinking water resulted in significantly elevated urinary release of PapAl which increased incrementally for the duration of the application. Release of
PapA2 and PapA3 was not affected and remained in the normal range. These results show that with the tests developed changes in the rat renal papilla caused by
xenobiotics can be detected early by urinary analysis and monitored during follow-up studies. Moreover. the different
antigen release patterns obtained after application of the different compounds suggest a possible differing mode of action.