Elevated levels of ornithine decarboxylase and polyamines in the kidneys of estradiol-treated male hamsters

The effects of 17 ß-estradiol (E₂) on the levels ofornithlne decarboxytase (ODC), S-adenosylmethionine decarboxylase(SAMDC), and of the polyamines putrescine, spermidine and sperminein the kidneys of castrated male hamsters were determined. Thei.p. injection of E₂ into male hamsters led to renal ODC levelsthree times above the control levels 6–12 h after treatment.Similarly, the renal ODC levels in hamsters treated with chronicdoses of E₂ for 60–180 days were 13–1.9 times thecorresponding enzyme levels in control, sham-operated animals.With a series of estrogen analogues, there was a direct correlationbetween the rise in renal ODC in vitro and the binding to renalestradiol receptor sites in vitro. The hamster kidney levelsof the polyamines putrescine, spermidine and spermine all declinedduring the 180-day experimental period. A single i.p. injectionof E led to a 70% increase in renal SAMDC activity 12 h aftertreatment. However, the administration of E for 180–270days was without effect on the normal age-dependent declinein SAMDC levels noted in kidneys. These results indicate that,like other carcinogens and promoters, E₂ increases the levelsof ODC and of polyamines in its target tissue and that the risein ODC is mediated by a specific estradiol-binding protein.