Opioids are responsible for neurochemical feminization of the brain in prenatally stressed male rats.

Objectives: To study the role of opioids in early postnatal changes of the hypothalamic testosterone metabolism and catecholamine content underlying feminizing effect of prenatal stress on male sexual behavior in rats.

Material And Methods: 10 day-old male and female offspring from mothers given naltrexone prior to daily 1-hour restraint during the last gestational week were used in the study. Aromatase and 5 alpha-reductase activities, noradrenaline and dopamine contents in the brain preoptic area and medial basal hypothalamus were studied by thin layer chromatography, radiometric and spectrofluorimetric techniques.