Androgen regulates gap junction mRNA expression in androgen-sensitive motoneurons in the rat spinal cord.

Expression of gap junction mRNA was examined in the androgen-sensitive motoneurons of the spinal nucleus of the bulbocavernosus (SNB) by in situ hybridization histochemistry using cDNA encoding rat liver gap junction protein (connexin 32). Hybridizable gap junction mRNA was localized on the somata and proximal dendrites of SNB motoneurons. The removal of androgen by castration dramatically reduced the expression level of gap junction mRNA in the SNB motoneurons, whereas this change was prevented by testosterone treatment. These results are the first demonstration of hormonal regulation of gap junction mRNA expression in the central nervous system.