4.2. In Vivo and Ex Vivo Data
Available pharmacokinetic data for spermidine are mainly limited to in vivo and animal models and suggest contradictory results. In a rodent ex vivo model, the portal vein recovery of In mouse models, prolonged administration of polyamine-rich chow was found to (partly sex-dependently) increase both spermidine and spermine blood levels [Interestingly, early in vivo experiments in rats with dietary polyamines from the 1990s revealed differential effects of presystemic eliminations. After intragastrical administration, only 11–15% of putrescine was recovered in intestinal tissue, but 87–96% of spermidine and 79–82% of spermine were recovered [