Y. Gao et Rv. Short, FERTILITY-CONTROL IN WILD MICE AFTER FEEDING WITH RU486 OR METHYL TESTOSTERONE, Journal of Reproduction and Fertility, 101(2), 1994, pp. 483-487
Paraffin blocks containing either no steroid, 150 mg RU486 kg(-1), 500
-mg methyl testosterone kg(-1) or 1500 mg methyl testosterone kg(-1) w
ere fed to wild mice (Mus musculus) in addition to the standard labora
tory diet in four large (3 m x 3 m) outdoor pens for six months over t
he summer. The RU486 bait was provided for only 3 days every 18 or 21
days, whereas the methyl testosterone bait was available continuously.
From a foundation stock of to mice (nine male, eleven female) in each
pen, the population had increased to 253 (control), 72 (RU486), 249 (
low methyl testosterone concentration) and 103 (high methyl testostero
ne concentration) at the end of six months, when 17%, 4%, 32% and 13%
of the mature females were pregnant in the respective treatment groups
. There was little evidence of an increase in the incidence of injurie
s in the androgen-treated animals. Daily estimation of water consumpti
on in the pens proved to be a good non-invasive way of monitoring popu
lation growth during the course of the experiment. Intermittent feedin
g with a low concentration of RU486 appeared to be much more successfu
l in inhibiting reproduction than continuous feeding with a high conce
ntration of methyl testosterone, and it therefore offers a new method
for controlling feral mouse populations.