New research may provide an explanation for infertility

Thanks to husband and wife team of Yuriy Kirichok and Polina Lishko, we now are closer to understanding the inner workings of sperm cells, and the final stages of fertilization. The pair have managed to observe and record electrical impulses in the sperm cell, caused by an influx of calcium into the cell body. These are caused because progesterone comes into contact with a substance in the sperm cell's membrane called CatSper, triggering an electrical impulse to go down the tail and "wiggle" propelling the cell forward. Kirichok and Lishko observed healthy cells using this surge of electrical current, and infertile sperm cells without the CatSper substance. The CatSper substance is triggered in the final stage of fertilization, after the sperm pushes through the outer membrane of the egg cell. This causes a final hyperactivation of the tail, propelling the sperm into the inside of the egg. A possible use for these findings might be in the form of a birth control drug for humans, by preventing the CatSper substance from becoming activated. We discussed the stages of fertilization in class, as well as hormones such as progesterone.