Steroid regulation of calcitonin gene-related peptide mRNA expression in motoneurons of the spinal nucleus of the bulbocavernosus.
Motoneurons express calcitonin gene-related peptide (CGRP). Previous studies have shown that CGRP immunoreactivity is regulated by testosterone in the androgen-sensitive motoneurons of the spinal nucleus of the bulbocavernosus (SNB). In this research the effect of plasma levels of testosterone on the expression of alpha CGRP mRNA in the SNB motoneurons of adult male rats was studied with in situ hybridization. The number of motoneurons expressing alpha CGRP mRNA and the level of alpha CGRP mRNA expression was significantly higher in the SNB of castrated male rats than in the SNB of gonadally intact rats. Using a 5x background labeling criterion in castrated rats 88.1 +/- 4.5% while in intact rats 75.3 +/- 6.4% of SNB motoneurons expressed alpha CGRP mRNA. Testosterone replacement at the time of castration prevented the effect of castration on the expression of alpha CGRP mRNA in SNB motoneurons. In castrated rats, the increase in the number of SNB cells expressing CGRP was the result of increased steady state levels of alpha CGRP mRNA in all SNB neurons.
Popper
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Department of Anatomy and Cell Biology, UCLA School of Medicine 90024.
Micevych
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D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D008297:Male; D009046:Motor Neurons / Q000187:drug effects / Q000378:metabolism*; D009919:Orchiectomy; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D012727:Sex Characteristics; D013739:Testosterone / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects
D012333:RNA, Messenger; D013739:Testosterone; D015740:Calcitonin Gene-Related Peptide