Perinatal androgen administration and the maintenance of sexually dimorphic and nondimorphic lumbosacral motor neuron groups in female Albino Swiss rats.

Motor neuron groups in the L5-S1 region of the spinal cord were examined in male and female Albino Swiss rats and in females treated with 5 alpha-dihydrotestosterone benzoate (DHTB) either prenatally or postnatally. The spinal nucleus of bulbocavernosus (SNB) contained some five times more neurons in males than females. Perinatal DHTB treatment to females increased SNB numbers; prenatal treatment was less effective than postnatal. Within the same part of the cord, males possessed more motor neurons in the dorsolateral nucleus (DLN) than females. Perinatal DHTB treatment to females (both prenatal and postnatal) increased DLN neuron numbers. The perineal muscles (the normal target for SNB and DLN motor neurons) are absent in adult female rats; they are maintained by postnatal (but not prenatal) DHTB treatment. Two other motor neurons groups within the same region of cord, the retrodorsolateral nucleus (RDLN) and the ventromedial nucleus (VM) show no sex differences and are not affected by perinatal androgen treatment.