Ovulation in rabbits following intravenous and intracerebral administration of copper sulphate

The present authors (1965) previously reported that the site of action of copper sulphate in the induction of ovulation might be in the vicinity of the posterior median eminence (PME) in the hypothalamus. The authors have now injected a solution of copper sulphate intravenously into adult female Japanese mongrel rabbits and also infused the solution directly into the PME of the hypothalamus. The 50% effective dose for inducing ovulation in some of the rabbits of the tested group was 0.76 μg/kg of copper sulphate in the PME infusion or 3.0 mg/kg in the intravenous injection. This means that the 50% effective dose of copper sulphate required for infusion into the PME is 1/4000 of the 50% effective dose required by intravenous injection.