Copenhagen rat prostatic tumor ornithine decarboxylase activity (ODC) and the effect of the ODC inhibitor alpha-difluoromethylornithine.

The R3327MAT-Lu tumor is a rapidly growing anaplastic derivative of the Dunning R3327 prostatic adenocarcinoma. We have found the ornithine decarboxylase (ODC) activity of this tumor to be as sensitive to inhibition by alpha-difluoromethylornithine (DFMO) as normal rat prostate. The same was true for all the other R3327 tumor derivatives we studied. The in vivo inhibition of ODC by DFMO allowed increased uptake of exogenously administered putrescine by the R3327AT tumor. Further, DFMO was inhibitory to the growth of the R3327MAT-Lu both in vitro and in vivo.