Аннотация:This study was conducted to reveal a possible influence of cat urine on reproductive development in male Campbell's hamsters (Phodopus campbelli). In Experiment 1, males were treated every other day with cat urine or water (control) from Day 11 (D 11). At D30 body and epididymis weights were significantly reduced but relative adrenal gland weight was higher in cat urine treated juveniles. These data suggest that the suppressive influence of cat urine on reproductive development involves the adrenal-pituitary axis and cat urine could be considered a stress factor. Experiment 2 was done to check whether decreases in epididymis weight correspond with meiotic disturbance in prepubertal hamster males.Males were exposed to cat urine or water from DIS until D45. At D45 males were unilaterally gonadectomized and electronmicroscopic analysis of spread spermatocyte preparations was performed. The analysis of synaptonemal complexes (SC) of pachytene nuclei revealed no abnormalities in either sex chromosomes or autosomes in control hamsters. However, in the cat urine treated group, abnormal SC configurations that included partial autosomal asynapsis combined with interlocking and sex chromosome dissociation were found. These data indicate that the disturbance of homologous synapsis at the first meiotic prophase may at least in part explain the decrease of epididymis weight in cat urine treated hamsters.