Abstract
Bladder tumor was induced in rats by oral administration of 0.025% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN), after which Con A response of thymus lymphocytes as well as the effect of calf thymus humoral factor (THF) on Con A response were studied.
The results of this study are as follows.
1. Con A response of thymus lymphocytes began to decrease from the 8th week after BBN administration when the change in the mucous membrane such as hypertrophy in the bladder wall or vascular formation were noted, and a marked decrease in the response was noted from the 15th week when the tumor was visually recognizable. At the 20th week after BBN administration, massive hematuria was noted and the tumor was visually observed in about 95% of the rat bladders.
2. When THE extracted and prepared according to Goldstein et al. was applied in vitro to the thymus lymphocytes culture, an enhancement of Con A response of thymus lymphocytes was induced in the period between 8th and 20th weeks after BBN administration. However, after the 20th week, when the tumor in the bladder was observed in over 95% of the rats, the effect of THE was not clearly detectable.
3. In the period between 8th and 20th weeks after BBN administration, THE sensitive thymus lymphocytes, induced an enhancement of Con A response by the factor, were mainly separated in the low density fraction when rat thymus lymphocytes were separated into three fractions by discontinuous density gradient centrifugation combined with adhesion column method.
