The Role of Zinc in Male Fertility
Zinc ion is crucial for sperm cell functioning and zinc supplements may be beneficial in treating male infertility
Several studies proposed the importance of zinc ion in male fertility. Here we describe the properties, roles, and cellular mechanisms of action of zinc ion (Zn2+) in spermatozoa, focusing on its involvement in three functions crucial for successful fertilization: sperm motility, capacitation (the stage where the sperm becomes hypermotile, i.e., has increased circular motility), and acrosomal exocytosis (the process by which the sperm cell takes the form of an arrowhead that allows penetration into the egg).
The impact of zinc on sperm motility has been investigated in many vertebrate and invertebrate species. The presence of zinc ion in the extracellular environment affects the zinc ion receptor in the cell. Studies have found that this receptor, called GPR39, is situated in the sperm tail and the acrosome –an anterior prolongation of a sperm cell that releases egg-penetrating enzymes. This finding suggests that zinc ion is involved in sperm motility and acrosomal exocytosis.
The study by Deborah Allouche-Fitoussi and Prof. Haim Breitbart of the Goodman Faculty of Life Sciences indicates that the GPR39 receptor stimulates human sperm hyper-activated motility and acrosomal exocytosis. Zinc ion activates the receptor, which leads to a chain of biochemical reactions that result in increased sperm motility and the formation of actin protein fibers essential for normal capacitation.
The researchers conclude that zinc ions are crucial for male fertility, and these findings may also help to improve fertility of men and farm animals. The appropriate concentration of zinc ion in the seminal fluid is essential for the proper functioning of the sperm and for fertilization. However, relatively high concentrations of Zn2+ may impair sperm quality. Although many studies show a link between the concentration of zinc ion in semen and the physiology of the sperm cell, it cannot be determined that zinc deficiency in semen is a source of infertility. A micromolar supplement of zinc ions to the seminal fluid contributes to improved sperm motility, capacitation, and fertilization. Zinc supplements should be considered as a positive factor in male fertility treatments.
To read the full article in the International Journal of Molecular Sciences