Wiktionary
spermidine
n. (context organic compound English) The triamine ''N-(3-aminopropyl)butane-1,4-diamine'', originally obtained from semen, that is involved in cell metabolism.
Wikipedia
Spermidine
Spermidine is a polyamine compound found in ribosomes and living tissues, and having various metabolic functions within organisms. It was originally isolated from semen.