Effect of Urease Injections on Ehrlich Ascites Tumor Growth in Mice

Abstract

Summary

Mature male Swiss Webster mice bearing solid and ascitic forms of Ehrlich ascites tumor (EAT) were injected with 0.1 to 0.4 unit of crystalline jack bean urease per injection. Mice given 12 × 10⁶ EAT cells sc and injected with 0.4 unit of enzyme at 12 and 24 hr thereafter had tumors at 3 weeks which weighed 40% of those in mice given 0.85% NaCl instead of urease. Liver, spleen, and brain weight changed significantly in mice bearing solid EAT and this change was reduced significantly in urease-treated animals. Animals given 0.4 unit of urease as described above showed a significant reduction in body weight compared to non-urease-treated animals. Mice bearing ascitic EAT injected with 0.2 unit of urease on days 6 and 7 after EAT inoculation and killed 5 days thereafter showed significant elevations of ascitic fluid ammonia and cell to ascitic fluid volume ratio, The latter urease-treated animals showed a significant decrease in body weight at 24 and 48 hr after the second urease injection. The half-time (days) for disappearance of ³H-thymidine from DNA in EAT cells growing intraperitoneally were 2.93 ± 1.05 and 3.69 ± 1.71 in urease- and saline-treated animals, respectively. Mice given 0.2 unit of urease at 12 hr before and at 12, 24, and 36 hr after EAT cells were given ip showed a significant reduction in the number of animals with tumors at 21 days and a persistent depression in body weight. Tumor-bearing animals injected with urease showed a depression in colonic temperature and feed intake.