Prenatal flutamide alters sexually dimorphic nuclei in the spinal cord of male rats.

The effects of prenatal exposure to the antiandrogen flutamide on two sexually dimorphic nuclei of the lumbar spinal cord, the dorsolateral nucleus (DLN) and the spinal nucleus of the bulbocavernosus (SNB), were investigated. Rat dams were given daily injections of 5 mg flutamide or vehicle alone from day 11 through 21 of pregnancy. The spinal cords and perineal morphology of their male and female offspring were examined in adulthood. Flutamide reduced the number of SNB and DLN neurons, reduced the somal and nuclear area of SNB neurons, and reduced the weight of the perineal muscles in males. Flutamide produced no effect in females. No sexual dimorphism was found in the mean somal area of DLN neurons, but a sexual dimorphism was found in the distribution of somal areas in our samples; females had proportionately more large neurons than males. Flutamide-treated males also had proportionately more large neurons than control males but fewer than females. A sexual dimorphism was found in the nuclear areas of DLN neurons but flutamide did not influence this trait.