LAUSR

BACKGROUND Currently, many prostate cancer patients, detected through the prostatic specific antigen test, harbor organ-confined indolent disease that cannot be differentiated from aggressive cancer according to clinically and pathologically known measures. Spermine has been considered as an endogenous inhibitor for prostate-confined cancer growth and its expression has shown correlation with prostate cancer growth rates. If established clinically, measurements of spermine bio-synthesis rates in prostates may predict prostate cancer growth and patient outcomes. Using rat models, we tested the feasibility of quantifying spermine bio-synthesis rates with 13 C NMR. METHODS Male Copenhagen rats (10 weeks, n=6) were injected with uniformly 13 C-labeled L-ornithine HCl, and sacrificed in pairs at 10, 30 and 60 min after injection. Another two rats were injected with saline and sacrificed at 30 mins as controls. Prostates were harvested and extracted with perchloric acid and the neutralized solutions examined by 13 C NMR at 600 MHz. RESULTS 13 C NMR revealed measurable ornithine, as well as putrescine-spermidine-spermine syntheses in rat prostates allowing polyamine bio-synthetic and ornithine bio-catabolic rates to be calculated. CONCLUSIONS Our study demonstrated the feasibility of 13 C NMR in measuring bio-synthesis rates of ornithine to spermine enzymatic reactions in rat prostates. The current study established a foundation on which future investigations of protocols that differentiate prostate cancer growth rates according to the measure of ornithine to spermine bio-synthetic rates may be developed.