This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The objective of this study was to determine effects of mercuric chloride (MC) treatment on sperm functions (number, motility, morphology), and to determine whether the MC-induced lower fertility resulted from adverse effects on males, females, or both. Both male and female rats were treated with MC at a dose of 2.5 mg/kg or de-ionized water (controls) daily, from 1-90 days of age in the case of males or from 1-111 days of age in the case of females (20 additional days of lactation). Results revealed that mercuric chloride exposure resulted in i) reduced weight of the testis, epididymis, and prostate; ii) reduced number of sperm in the testis and epididymis; iii) increased incidence of abnormal sperm in semen; iv) reduced percentage of motile sperm and progressively forward moving sperm; v) lower concentration of 17 beta estradiol, but without any alteration in serum testosterone or LH level; and vi) decreased fertility index by almost 20%. The reduction in fertility index probably resulted from toxic effects of mercury on sperm parameters, although the relative contribution of each sperm parameter (for example, number, morphology, or motility) in lowering male fertility remains to be determined. Similarly, mercuric chloride exposure lowered fertility index in females. But, compared to males, the reduction in fertility was much higher (reduced by almost 40% vs 20% in males), despite without any reduction in the weight of the ovary and uterus. Hence, these results suggest a higher toxic effect of mercuric chloride exposure on female fertility. In conclusion, results provide evidence for toxic effects of mercury on reproductive organs and fertility in males and on fertility in females, but the mechanism of lower fertility remains unclear.
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