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GENDER-SPECIFIC DIFFERENCES IN THE RESPONSE OF MATURING GAMETES TO TOXIC INSULT
Citation:
Darney, S P. GENDER-SPECIFIC DIFFERENCES IN THE RESPONSE OF MATURING GAMETES TO TOXIC INSULT. Presented at Gender Differences in Reproductive Biology and Toxicology, Tucson, AZ, November 9-11, 2000.
Description:
GENDER-SPECIFIC DIFFERENCES IN THE RESPONSE OF MATURING GAMETES TO TOXIC INSULT
Sally D. Perreault, U. S. Environmental Toxicology Division, National Health and Environmental Effects Research Laboratory, Reproductive Toxicology Division, Research Triangle Park, NC 27711
Fundamental differences in the biology of gamete maturation forecast the differential response of developing oocytes and spermatozoa to toxicant insult. The male germ cell has completed meiosis and undergone significant differentiation in the testis to become a mature spermatid by the time it is released into epididymis for its final maturation. During the maturational changes in the testis and excurrent ducts, toxicants that alter Sertoli cell function, epididymal function and/or the hormonal support of these tissues may impact negatively upon sperm maturation, as may toxicants that react directly with the spermatozoon itself. On the other hand, when the oocyte responds to the pre-ovulatory surge of luteinizing hormone and enters its maturational phase, it has to complete both meiotic divisions, the first while still in the ovarian follicle. Both gametes finalize their maturation in the female tract; therefore, toxicants present in the female at this critical time may impact either gamete. In response to factors in the oviduct, the spermatozoon undergoes capacitation near the site of fertilization. It must then be capable of responding to signals from the oocyte and its vestments during the course of fertilization. The oocyte, in turn, completes it's second meiotic division only after being penetrated and activated by the fertilizing spermatozoon. With each gamete being highly specialized to play its role in the fertilization process, it is not surprising that each would be uniquely susceptible to toxicants with varying cellular targets and mechanisms of action. This talk will highlight examples of gender-specific susceptibility to selected gamete toxicants. A systematic understanding of these differences is important for testing the default assumptions used in risk assessment wherein effects of xenobiotics on male and female reproductive processes are assumed generally to be similar unless demonstrated otherwise.
This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.