Ultrastructural and metabolic changes in the neuropeptide Y-containing striatal neuronal network after thermocoagulatory cortical lesion in adult rat

Prenatal melatonin exposure affects luteinizing hormone and hypothalamic and striatal neuropeptide Y in the male rat offspring

The present study examines the influence of prenatal melatonin on the hypothalamic and striatal neuropeptide Y (NPY) concentrations as well as on luteinizing hormone (LH) levels. Male rat offspring of control and melatonin treated mother rats were studied at different ages of the sexual development: infantile, prepubertal, pubertal and adult ages. Hypothalamic NPY levels were much higher during the juvenile than throughout the infantile period. After prenatal melatonin treatment significantly higher values since day 15 up to 35, also at 60 days of age were found, as compared with controls. Striatal NPY levels were lower than in hypothalamus. Again, NPY in the striatum from offspring of melatonin treated mother rats showed significantly higher values than the respective controls at most of the ages studied. However, prenatal melatonin exerted an inhibitory influence upon LH secretion pattern, since decreased concentrations up to 25 days of age and delayed peak values at pubertal age were observed. The present study also suggest that the effect of NPY upon LH secretion is related to sexual development, since NPY exerted opposite effect in infantile than in pubertal period and melatonin administration during intrauterine life prevented this effect.