The results indicate that cells can tolerate shrinking and swelling only to 0.97 and 1.02 times their isosmotic cell volume and still maintain > 70% motility. These tolerance limits are broadened somewhat in the presence of an extender, which may be the result of plasma membrane modification or stabilization by the extender. Previous reports support the notion that extenders may interact with boar spermatozoa plasma membranes, allowing for extended cell viability. For example, it has been reported that certain extender components, such as BSA, can remove lipid breakdown products from membranes, thereby changing membrane permeability. The ANDROHEP extender has been reported to allow boar spermatozoa to regulate cell volume over prolonged periods of time. buy levaquin online
Extenders containing low-density lipoprotein fractions of egg yolk have been shown to modify protein components of the cells, thereby enhancing protection during storage. Graham and Foote revealed that media containing specific lipids, phosphatidylserine alone or in combination with phosphatidylcholine, can protect sperm during cooling. Further experiments should be conducted to determine the mechanism for extender protection of boar spermatozoa, and, more specifically, to determine what components of the extender offer this protection. In addition, a more thorough investigation should be conducted regarding the interaction between extender components and osmotic tolerance limits.