Neonatal testosterone treatment increases neuron and synapse numbers in male rat superior cervical ganglion.
Neonatal treatment with gonadal steroids has been reported to alter morphological as well as functional development in various regions of the brain and spinal cord. Among the observed alterations are changes in numbers of neurons and in the organization and numbers of synapses. These regions have been found to be sexually dimorphic, and the dimorphism dependent upon gender differences in circulating levels of gonadal steroids. Neonatal treatment with testosterone has been shown to produce an increase in the number of neurons in the superior cervical sympathetic ganglion in female rats. The present studies were designed to investigate the possibility of a normally occurring sexual dimorphism in the SCG of the rat, and to characterize the effect of neonatal treatment with testosterone on neurons and synapses in the male rat. We report a sexual dimorphism in the number of neurons but not in the number of preganglionic axons or ganglionic synapses. In addition, neonatal administration of testosterone propionate results in a 40% increase in the number of superior cervical ganglion neurons in treated male rats over the control male number at 15 and 30 days of age. The testosterone propionate treatment results in a 66% increase in the number of synapses in male superior cervical ganglia, without a concomitant increase in the number of preganglionic axons.
D000818:Animals; D000831:Animals, Newborn; D001369:Axons / Q000187:drug effects; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects*; D005260:Female; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000187:drug effects*; D008297:Male; D009474:Neurons / Q000187:drug effects; D051381:Rats; D012737:Sex Factors; D013569:Synapses / Q000187:drug effects*; D013739:Testosterone / Q000494:pharmacology*
D013739:Testosterone