FROM headbanging to pirouettes, sperm cells need the right moves to bag the egg. Identifying how sperm switch from one movement to another could lead to better fertility treatments for men, it now seems.

Identifying how sperm switch from one movement to another could help to treat infertile men

In the journey up the female reproductive tract, sperm cells have to plough through a range of viscous barriers, says Stephen Publicover at the University of Birmingham, UK. To do this they have to adapt their behaviour accordingly.

Broadly speaking, sperm are either activated, swimming forwards in a spiral, or hyperactivated, thrashing wildly – used to enter the egg.


To find out how sperm switch from one stroke to the other, Publicover and his colleagues studied calcium signalling in human sperm cells. Sperm cells appeared to be activated when calcium enters through ion channels in the tail. When calcium is released from organelles inside the neck of the cell into the surrounding cytoplasm, the sperm became hyperactivated.

To verify the finding, the team used drugs such as progesterone to artificially stimulate the movement of calcium within a sperm sample. When they triggered calcium uptake through the tail of the sperm, it stimulated activated movement and the sperm moved along a mucus-filled tube more easily than in a drug-free sample. Similarly, triggering the release of calcium within the neck made the sperm hyperactivated. The work was presented last week at Fertility 2013 in Liverpool, UK.

It is not yet clear what influences calcium movement within the reproductive tract, but varying pH levels throughout may be involved.

The work may have relevance in identifying types of infertility involving sperm switching between movements, says John Parrington at the University of Oxford. “Or for making new types of contraceptive.”