Gene expression profiles of prepubertal male and female gonadotropin releasing hormone neurons

Appropriate regulation of gonadotropin releasing hormone (GnRH) neurons is essential for successful reproduction of vertebrates. At present, several neuropeptide and monoamine systems in the brain are known to participate in the control of GnRH neuronal activities, however, many questions remain about the identity of the control mechanisms in GnRH neurons. In order to identify such factors and mechanisms, we extracted cytoplasm from identified, individual GnRH neurons of transgenic mice and used gene array microchip technology to establish expression profiles of prepubertal male and female GnRH neurons. About 3,400 genes and Expressed Sequence Tags (ESTs) were identified in the GnRH neurons. While most genes were expressed in both, male and female GnRH neurons at similar levels, distinct differences were seen in the expression of certain growth factors, extracellular matrix proteins, receptors and transcription factors. The results show that many additional transmitters and growth factors participate in the control of GnRH neuronal activity and that the sexual dimorphism in the regulation of GnRH neurons may be caused by different expression levels of relatively few genes.