Fertility control in laboratory rats and mice after feeding with the antigestagen RU486

Journal of Reproduction and Fertility
Y Gao, R V Short


The intermittent use of an antigestagen could prove to be a very effective way of controlling the fertility of rats and mice in the wild. This concept was tested by giving paraffin wax blocks containing cereal grains and the antigestagen Mifepristone, RU486 (150 mg kg-1 block) to male and female laboratory rats and mice in a series of free-choice feeding experiments. There was no significant difference in the consumption of blocks with or without RU486, showing that it was completely palatable to rats and mice, and no aversion developed following refeeding. The average consumption of RU486 by rats was 11 mg kg-1 day-1; mice consumed 37 mg kg-1 day-1. All the females showed persistent oestrous vaginal smears throughout the treatment. When male and female rats and mice were given continuous access to treated paraffin blocks for 30 days, no conceptions occurred. At the end of this time, there was a significant increase in ovarian weight in the treated rats and mice, but no difference in testicular weight. Treated blocks were given to rats for 3 days every 21 days for a total of 115 days. Four dead litters were produced following the first antigestagen treatment on day 21, but no more litters were produced and no treated rats were ...Continue Reading


Aug 23, 2008·Reproduction : the Official Journal of the Society for the Study of Fertility·Hong ZhouShinichi Ohno
Oct 7, 2008·Toxicology and Applied Pharmacology·Giovanna LazzariCristian Pellizzer

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