[Effect of p-chlorophenylalanine on rat reproduction under different conditions of lighting (author's transl)].

Reproduction in female rats kept on artificial cycles of light/darkness, continuous lighting and continuous darkness, has been studied. Three weekly doses of p-chlorophenylalanine (p-CPA), 100 mg/kg, were given to half of the rats in each group during the two preconditioning months before copulation. An evaluation has been made of the insemination, fecundation, number of embryos, ovarian cycle and level of 5-HT in the hypothalamus. The administration of p-CPA had an inhibitory effect on the reproductive behavior, especially pronounced in rats kept under continuous lighting and under continuous darkness. The difference in 5-TH levels were greater among the groups kept on cycles of light/darkness without treatment and with p-CPA (0.05 greater than P greater than 0.01). The importance of 5-HT in the mechanisms of reproductive behavior is emphasized.