title: Steroid receptor coactivator-1 is not required for androgen-mediated sexual differentiation of spinal motoneurons.
abstract: Steroid receptor coactivator-1 (SRC-1) amplifies genomic steroid hormone signal transduction and has been implicated in steroid-mediated sexual differentiation of the mammalian nervous system. We investigated the possible effect of an SRC-1 null mutation on 2 morphological endpoints of androgenic signaling: the number and size of motoneurons within the spinal nucleus of the bulbocavernosus (SNB). In wild-type C57/BL6 mice, SRC-1 immunoreactive nuclei were observed within the SNB and one of its target muscles, the levator ani. However, SRC-1 null mice were indistinguishable from sex-matched wild-type littermates in both SNB number and cross-sectional area of SNB motoneurons. Similarly, we found no difference between SRC-1 null and wildtype littermates in the number or size of motoneurons in the retrodorsolateral nucleus, a motor pool that is not typically sexually differentiated in either number or size. These results demonstrate that SRC-1 is not essential for the development and maintenance of a sexually dimorphic neuromuscular system.
authors.affiliation: Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Monks
authors.forename: Jianming
authors.initials: J
authors.lastname: Xu
authors.forename: Bert W
authors.initials: BW
authors.lastname: O'Malley
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Jordan
mesh_terms: D000728:Androgens / Q000502:physiology*; D000818:Animals; D051548:Histone Acetyltransferases; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009046:Motor Neurons / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000294:innervation; D056920:Nuclear Receptor Coactivator 1; D011987:Receptors, Steroid / Q000378:metabolism*; D012733:Sex Differentiation; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000728:Androgens; D011987:Receptors, Steroid; D014157:Transcription Factors; D051548:Histone Acetyltransferases; C538861:Ncoa1 protein, mouse; D056920:Nuclear Receptor Coactivator 1