AGE-DEPENDENT CHANGES IN ANDROGEN RECEPTOR IMMUNOREACTIVITY IN MOTONEURONS OF THE SPINAL NUCLEUS OF THE BULBOCAVERNOSUS OF MALE RATS

Androgen receptor (AR) immunoreactivity was examined in androgen-sensi tive motoneurons of the spinal nucleus of the bulbocavernosus (SNB) in young and old male rats by immunohistochemistry using the polyclonal antibody, PG21. In young animals, intense AR immunoreactivity was conf ined to the cell nucleus, but not in the nucleolus of SNB motoneurons. In old animals, both the intensity of AR immunoreactivity in the nucl ei and number of AR immunoreactive nuclei of the SNB motoneurons were significantly reduced. Plasma levels of testosterone in old animals we re significantly smaller than those in young ones. Age-dependent chang es both in AR expression of SNB motoneurons and plasma levels of andro gen seem to correlate with the aging of the SNB system. (C) 1998 Elsev ier Science Ireland Ltd.