Calcium homeostasis is regulated by spermine in mammalian spermatozoa

H. Breitbart, S. Rubinstein

Research output: Contribution to journalArticlepeer-review


Calcium uptake by ejaculated ram spermatozoa is enhanced approximately two-fold by 1-2 nM spermine. However, there is a concentration-dependent reversal of this stimulation when the polyamine concentration is raised to 10 nM. Spermine decreases the Km for Ca2+ from 2.5 mM to 0.5 mM. These experiments were performed in the presence of lactate, conditions under which 90% of the cell calcium is in the mitochondria. However, calcium uptake into extramitochondrial regions (in absence of lactate) induced by Ca2+-ionophore, is 50% inhibited by 10 mM spermine. This concentration of spermine causes also 50% inhibition in acrosomal exocytosis induced by Ca2+-ionophore. The data indicate that spermine controls acrosomal exocytosis by modulating Ca2+ transport into spermatozoa.

Original languageEnglish
Pages (from-to)153-163
Number of pages11
JournalMolecular Andrology
Issue number3-4
StatePublished - 1995


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