Effect of intrauterine injection of chlorpromazin on implantation in the rat

In rats, injection of chlorpromazin hydrochloride (CPZ), a calmodulin antagonist, to each uterine horn had a significant (87%) anti-implantation effect and 100% antifertility effect. Both of these rates were zero in the saline control group. Polyacrylamide gel electrophoresis analysis of the uterine fluid showed a decrease in the protein content and certain changes in its chemical composition, in particular, a marked reduction in the number of bands of estradiol-induced 70 kD proteins in the experimental group. No significant difference was found in the ovarian weight and the serum estradiol (E-2) and progesterone (P) levels between the two groups. These results suggest that calmodulin influences the process of implantation and this effect is not directly related to the serum concentrations of E-2 and P. It is believed that CPZ probably exerted its antiimplantation effect by a direct action on the uterus. (C) 1998 Elsevier Science Inc. AII rights reserved.