Metabolic Stability of α-Methylated Polyamine Derivatives and Their Use as Substitutes for the Natural Polyamines

• Published in: The Journal of biological chemistry 2005-02, Vol.280 (8), p.6595
• Main Authors: Aki Järvinen, Nikolay Grigorenko, Alex R. Khomutov, Mervi T. Hyvönen, Anne Uimari, Jouko Vepsäläinen, Riitta Sinervirta, Tuomo A. Keinänen, Slavoljub Vujcic, Leena Alhonen, Carl W. Porter, Juhani Jänne
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M412788200

Metabolically stable polyamine derivatives may serve as useful surrogates for the natural polyamines in studies aimed to elucidate the functions of individual polyamines. Here we studied the metabolic stability of α-methylspermidine, α-methylspermine, and bis-α-methylspermine, which all have been reported to fulfill many of the putative physiological functions of the natural polyamines. In vivo studies were performed with the transgenic rats overexpressing spermidine/spermine N 1 -acetyltransferase. α-Methylspermidine effectively accumulated in the liver and did not appear to undergo any further metabolism. On the other hand, α-methylspermine was readily converted to α-methylspermidine and spermidine; similarly, bis-α-methylspermine was converted to α-methylspermidine to some extent, both conversions being inhibited by the polyamine oxidase inhibitor N 1 , N 2 -bis(2,3-butadienyl)-1,4-butanediamine. Furthermore, we used recombinant polyamine oxidase, spermidine/spermine N 1 -acetyltransferase, and the recently discovered spermine oxidase in the kinetic studies. In vitro studies confirmed that methylation did not protect spermine analogs from degradation, whereas the spermidine analog was stable. Both α-methylspermidine and bis-α-methylspermine overcame the proliferative block of early liver regeneration in transgenic rats and reversed the cytostasis induced by an inhibition of ornithine decarboxylase in cultured fetal fibroblasts.