Hyperthermia and polyamine biosynthesis: Decreased ornithine decarboxylase induction in skin and kidney after heat shock

Abstract

The effect of hyperthermia treatments on ornithine decarboxylase (ODC) induction in mouse tissue was determined both ` in ` vitro and ` in ` vivo . ` In ` vitro , the addition of 12-O-tetradecanoylphorbol-13-acetate (TPA) to adult mouse skin pieces incubated at 37°C in serum-free MEM led to a dramatic increase in epidermal ODC activity 5 hours following treatment. In contrast, incubation temperatures of 40°C for the entire 5 hour incubation period rendered the skin pieces unresponsive to TPA for ODC induction. This inhibition of ODC induction was not the result of thermal skin kill, inactivation of TPA, or a general effect on epidermal protein synthesis. The inhibition of ODC induction could be reversed by switching the incubation temperature back to 37°C. ` In ` vivo , raising the core body temperature in male mice to 41°C for 1 hour resulted in a 78% decrease in kidney ODC activity. The kidney DNA synthesis and protein synthesis remained unaltered following the whole body hyperthermia treatments.