EFFECT OF DEPRIVATION OF SEROTONIN BY P-CHLOROPHENYLALANINE ON INDUCTION AND MAINTENANCE OF PSEUDOPREGNANCY IN FEMALE RATS

The effect of serotonin synthesis inhibitor, p-chlorophenylalanine (PC PA), on induction and maintenance of pseudopregnancy as indicated by d eciduoma formation was examined in female rats. Animals were injected with 1 mg/kg b.wt. of reserpine on the day of metestrus, and silk thre ad was passed through and placed in the left uterine horn 3 days after reserpine to induce deciduoma. PCPA (100 mg/kg b.wt.) was injected da ily for 4 days before or after reserpine in 15 and 13 rats, respective ly. A single injection of PCPA was administered before reserpine in ni ne females. In another group of rats (N = 16), instead of PCPA, saline was injected four times before reserpine. Nineteen female rats were t reated with reserpine only as a control group. Results showed 89% of t he control and 81.3% of the saline-treated females had massive deciduo ma in traumatized uterine hem. In contrast, only 33.3% or 46.2% female s with daily treatments of PCPA for 4 days before or after reserpine s howed positive decidual reaction. In addition, 88.9% of females with s ingle injection of PCPA possessed uterine hems with deciduoma. These r esults suggest that 4 days of treatment with PCPA eliminate induction and/or maintenance of pseudopregnancy. Thus, some levels of serotonin are required to induce and maintain pseudopregnancy.