Prolonged sperm-storage is an adaptation to the reproductive cycle that is
most highly developed in bat. Twenty four bat species have been identified so far to
store spermatozoa for the period of approx. 16 days up to ~225 days and still retain
fertilizing capacity. The aim of this review is to evaluate the mechanism and molecules
necessary for sperm to become efficiently stored in female genital tract. Spermatozoa
are arranged with their head towards the reproductive tract epithelium are characterized
in all sperm storing bat species so far investigated, suggesting that such intimate
relationships are an integral part of the mechanism of prolonged storage of sperm.
Recent study suggests that the ultimate controls of the mechanism underlying spermstorage
are hormonal. It has been demonstrated that sperm stored in female bat contains
high circulating level of androgen during the period of sperm storage. It is suggested
that androgen creates a unique microenvironment that facilitates prolonged sperm
storage. The identification of the specific molecules responsible for prolonged spermstorage
may suggest a mechanism to keep the sperm viable for prolonged period for
use in assisted reproductive technique.
Keywords: Androgen, Apoptosis, Bat, Female, Sperm, Storage.
