Mode of action of a new non-steroidal post-coital antifertility agent (Centchroman: 67/20 CDRI) in rats

Abstract

The estrogenicity and antiestrogenicity of the compound, 67/20 CDRI, have been studied using uterine and liver glycogen and uterine sialic acid as biochemical parameters. Estradiol caused significant increases in uterine and liver glycogen 6 and 18 hours after administration; whereas, compound 67/20 caused a marked increase in uterine glycogen at 6 hours which plateaued at this level for 48 hours after treatment. Liver glycogen showed a steady increase even 48 hours after the administration of 67/20. Uterine sialic acid in estrogen treated rats reached a peak level at 6 hours, decreased significantly by 18 hours and plateaued at this level up to 48 hours. Compound 67/20, on the other hand, caused an increase in uterine sialic acid 18 hours after the administration of the drug. Pretreatment with the compound for either 6 or 48 hours inhibited the estradiol-induced increase in uterine and liver glycogen and also uterine sialic acid. However, simultaneous administration of the compound with estradiol-17β was effective only in inhibiting the estradiol-induced increase in uterine sialic acid. In light of the present data, it is concluded that the antiimplantation/antifertility action of the compound may be 67/20 due to its inherent estrogenic and antiestrogenic properties.