Possible neuroprotective effects of melatonin (pineal gland hormone) and epithalon (peptide preparation) on estrous cycles and the central part of the reproductive function regulation in female rats under the influence of unfavorable ecological factors were studied. Estrous cycles of young, mature, and aging rats exposed to light pollution were characterized. The daily dynamics and average daily content of biogenic amines in the hypothalamic areas responsible for gonadoliberin synthesis and secretion were studied in animals of different age groups. The influence of the chemical effect on the noradrenergic system of the medial preoptic area and the dopaminergic system of median eminence with arcuate hypothalamic nuclei was studied in a model of premature aging of the reproductive function. It was established that the introduction of melatonin (pineal gland hormone) and epithalon (peptide preparation) is able to remove a number of the disturbances in the hypothalamic and ovarian parts of the reproductive system observed under conditions of permanent lighting and neurotoxic 1,2-dimethylhydrazine xenobiotic on the experimental animals. The results obtained indicate an important role of the pineal gland in the development of the circadian signal required for realization of the pre-ovulatory peak of gonadoliberin secretion and a protective effect of melatonin and epithalon, which is able to smooth away unfavorable ecological effects on the reproductive function of female rats with normal estrous cycles.