The anti-implantation action of endosulfan in albino mice: possible mechanisms.
Endosulfan, a chlorinated pesticide, was administered orally for 7 consecutive days to a group of virgin pregnant albino mice at doses of 1 to 4 mg/kg/d to examine its effect on implantation. For comparison, a second group of animals received 5 microg/kg/d estradiol-17beta, a third group received similar quantities of olive oil. Autopsy on day 8 revealed that the olive oil-treated mice were pregnant with a normal number of implantations and a normal duration of diestrus. Treatment with estradiol-17beta completely inhibited implantation and significantly decreased the duration of diestrus with a concomitant increase in estrus. Treatment with 1, 2, or 3 mg/kg/d endosulfan neither inhibited implantation nor significantly changed diestrus, whereas 4 mg/kg/d endosulfan completely inhibited implantation, with the uterus showing no signs of implantation. This group exhibited a significant decrease in diestrus with a concomitant increase in estrus. In endosulfan-treated mice, no significant changes occurred in body and organ weight, except for a significant increase in uterine weight in groups treated with 4 mg/kg/d endosulfan or estradiol-17beta. Because endosulfan is neither tubal locking nor causes expulsion of the blastocyst from the uterus like estradiol-17beta, the pesticide might inhibit implantation by altering the estrogen-progesterone ratio essential for implantation.
Hiremath
M B
MB
Reproductive Toxicology Laboratory, Post-Graduate Department of Zoology, Karnatak University, Dharwad 580 003, India.
Kaliwal
B B
BB
D000818:Animals; D001755:Blastocyst / Q000187:drug effects; D004031:Diestrus / Q000187:drug effects; D010064:Embryo Implantation / Q000187:drug effects*; D004726:Endosulfan / Q000494:pharmacology*; D004958:Estradiol / Q000494:pharmacology; D004971:Estrus / Q000187:drug effects; D005260:Female; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides / Q000494:pharmacology*; D008297:Male; D051379:Mice; D011247:Pregnancy; D015053:Zygote / Q000187:drug effects
D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D004958:Estradiol; D004726:Endosulfan