The effects of chronic mercuric chloride ingestion in female Sprague–Dawley rats on fertility and reproduction

Thirty-days-old female rats were chronically exposed, for 60 days, to 1or 2 mg/kg/day of mercuric chloride or an equivalent volume of water, via gavage. At 90 days of age they were mated with unexposed males. At approximately day 13 of gestation necropsies were performed on the females. Data were collected on the number of implantations and non-viable implantations in the uterus. No physical signs of Hg intoxication were seen except in weight gain. There were significantly fewer implantations in the high HgCl₂ group, with significantly more non-viable implantations in the low and high HgCl₂ groups, compared to controls. Lower levels of progesterone and higher levels of pituitary luteinizing hormone (LH) were found in the high HgCl₂ group compared to controls, whereas pituitary follicle stimulating hormone levels (FSH), while not significant, showed a dose–response relationship to HgCl₂ levels. No difference was found in the number of corpora lutea. The experiment indicated low level chronic ingestion of mercuric chloride, in female rats, while not effecting ovulation, produced disruption of implantation and fetal viability. Lower progesterone levels, higher LH, and possibly FSH levels, indicate that mercuric chloride may have a disruptive effect in the corpora lutea which manifests itself after ovulation.