67Ga uptake and heparan sulfate content of Ehrlich solid tumor in mice
67Ga uptake and heparan sulfate (HS) content were investigated during the recovery of mouse kidney from acute immune complex glomerulonephritis induced by daily injections of bovine serum, and the binding of 67Ga to glomerular basement membrane (GBM) was studied in vitro. The results were as follows. 67Ga uptake in the kidney increased after the start of bovine serum injection, and peaked on the 20th day. The uronic acid content in 1.2 M NaCl-soluble fraction (which contained predominantly HS) and the hydroxyproline content (an index of collagen) were increased at the 10th day, reaching a maximum at the 20th day. This pattern of HS content was essentially the same as that of 67Ga accumulation in the kidney. Urinary protein and gamma-GTP activity peaked at the 5th day, and these patterns were different from that of 67Ga uptake. 67Ga binding to GBM was significantly inhibited by treatments with HS-degrading enzyme (heparitinase), nitrous acid, trypsin or papain. However, the binding to GBM was unaffected by treatment with chondroitinase ABC. These results provide further evidence that the 67Ga-binding substance in tumor tissues and inflammatory lesions is probably HS.