Control of spermidine and spermine levels in rat tissues by trans-4-methylcyclohexylamine, a spermidine-synthase inhibitor.

Masaki Kobayashi, Toshiko Watanabe, Yong Ji Xu, Minoru Tatemori, Hitomi Goda, Masaru Niitsu, Akira Shirahata, Keijiro Samejima

Index: Biol. Pharm. Bull. 28(4) , 569-73, (2005)

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Abstract

In rat tissues, a decrease in spermidine, accompanied by an increase in spermine was induced by the oral administration (once daily for either 1 week or 1 month) of trans-4-methylcyclohexylamine (4MCHA), a spermidine synthase inhibitor. This is similar to the changes observed in polyamine content when cell growth is arrested. The body-weight gain of the rats tended to decrease with increasing doses of 4MCHA. A decrease in spermidine, combined with a moderate increase in spermine, was observed dose-dependently in all of the tissues tested, with a relatively fast clearance of 4MCHA. Manipulating the polyamine content of tissues, by daily administration of 100 mumol 4MCHA for 1 week, made it possible to estimate the effects of simultaneously added spermidine or spermine on endogenous polyamine contents. The altered polyamine levels, obtained after daily administration for 1 week, were maintained during the extended 1-month period, with growth-dependent alteration. The results show it is possible to produce experimental rats with a higher spermine:spermidine ratio than control rats to investigate the physiological significance of spermidine downregulation and spermine upregulation in vivo.