Metoclopramide (MCP) in doses of 2.2 mg kg-body weight, being administered intraperitoneally to rats for 14 d, provokes a premature release of germ cells in the testes. The number of spermatozoa is reduced. I n addition the spermatozoa exhibit defects of head and tail structures. After the administration of M C P for 14 d, followed by a 14-d break in applying the drug, the number of spermatozoa in the lumen of the epididymal duct continues to be low. Many spermatozoa are damaged. Only after a 66-dbreak in MCP administration is the morphology of the seminiferous epithelium restored, and a large number of spermatozoa appear in the lumen of the epididymal duct. IntroductionIn men hyperprolactinaemia disturbs the function of the reproductive system. Besides such symptoms as lowering or complete eradication of potency and libido, oligo-, astheno-, and teratozoospermia, and even azoospermia are encountered (Segal et al., 1976; Rocco et al., 1983). According to Cameron et al. ( 1984) and Katovich et al. (1985) the causes of the poor state of the semen, are changes in the testis, consisting in the degeneration of the adluminal parts of Sertoli cells, as well as disappearance of the junction between Sertoli cells and spermatids. This is due to germ cell exfoliation. The inappropriate release of germ cells causes a reduction in the number of spermatozoa.Our studies on the model