It has become increasingly obvious during the last two decades that a multitude of cellular processes are highly dependent on adequate levels of polyamines (1–6). Too high concentrations of the polyamines are toxic to the cell and may induce cell death or apoptosis (7). On the other hand, too low concentrations may negatively affect anabolic events, such as the synthesis of DNA, RNA, and protein, eventually giving rise to cellgrowth arrest (6). Thus it is important for cells to maintain their polyamine concentrations within rather narrow limits. Polyamine homeostasis is achieved by a careful balance between synthesis, degradation, and uptake of the amines (3). The introduction of molecular techniques in studies concerning polyamine metabolism has revealed a complex network of regulatory mechanisms involved in the cellular control of polyamine levels.
- Farmakologi och toxikologi