Pharmakologische Beeinflußbarkeit des durch Procainzufuhr experimentell erzeugten Daueroestrus an Ratten

Summary

In female rats the continuous administration of 1 to 1.5 per cent procaine solution inhibits the normal cyclic periodicity and produces continuous oestrus.

This continous oestrus can be arrested, even during the continued administration of procaine, by central suppressing drugs with psychological effects (fluphenazin, benactyzin), anti-epileptic substances and narcotics (phenytoin, barbital, morphine, and bromides), and also non-specifically by high doses of atropine or by pyramidon and phenacetin. When the injection of these central suppressing drugs is stopped but the administration of the procaine is maintained, the continuous oestrus returns.

It is suggested that this continuous oestrus is due to a stimulating effect of procaine on the hypothalamus, resulting in a suppression of the physiological liberation of LTH.

The continuous oestrus under procaine is also arrested by injection of progesterone or anteron and returns when these injections are stopped.

Ovulation in rabbits which is produced experimentally by intravenous injection of copper sulphate was not inhibited by previous treatment with procaine. In rats with continuous oestrus due to procaine the condition was reversed by intravenous injection of copper sulphate. There were one or more oestrus cycles afterwards.

Rats in the condition of continuous oestrus do not accept the male. When this continous oestrus is stopped by drugs with psychological effects, they allow themselves to be mounted. They can also become pregnant, but none of the foetuses are carried to normal term.

These findings with procaine are considered to indicate a disturbance of the normal course of oestrus because, as a result of the inhibitory stimuli to the hypothalamus, LTH is not liberated.