Inhibition of histochemical reaction to SH groups by pharmacological agents as a preliminary test for the teratogenic activity.

Studies carried out with 34 chemicals (drugs or food additives) previously screened for the teratogenic activity revealed that the compounds which had shown teratogenic properties blocked or markedly depressed the intensity of an in vitro histochemical reaction for SH groups in fixed liver sections in Wistar rats. Most of the drugs devoid of the teratogenic activity did not affect the reaction of SH groups; only three of the compounds which did not show unequivocal teratogenic properties (but, nevertheless, produced few congenital malformations) inhibited the reaction. The results suggest that the ability of teratogenic chemicals to inhibit the histochemical reaction to SH groups in vitro may be employed in a preliminary in vitro test to screen drugs for teratogenicity.