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As the key regulator of reproduction, gonadotropin-releasing hormone (GnRH) is released by neurons in the hypothalamus, and transported via the hypothalamo-hypophyseal portal circulation to the anterior pituitary to trigger gonadotropin release for gonadal steroidogenesis and gametogene-sis. | MINIREVIEW Gonadotropin-releasing hormone regulation of the GnRH gene Vien H. Y. Lee Leo T. O. Lee and Billy K. C. Chow Schoolof BiologicalSciences The University of Hong Kong China Keywords estrogen follicle-stimulating hormone GnRH gonadotropin luteinizing hormone PKC signalling progesterone promoter steroid hormone transcriptional regulation Correspondence B. K. C. Chow School of Biological Sciences The University of Hong Kong Pokfulam Road Hong Kong China Fax 852 2559 9114 Tel 852 2299 0850 E-mail bkcc@hkusua.hku.hk Received 18 April2008 revised 4 August 2008 accepted 29 August 2008 doi 10.1111 j.1742-4658.2008.06676.x As the key regulator of reproduction gonadotropin-releasing hormone GnRH is released by neurons in the hypothalamus and transported via the hypothalamo-hypophyseal portal circulation to the anterior pituitary to trigger gonadotropin release for gonadal steroidogenesis and gametogenesis. To achieve appropriate reproductive function mammals have precise regulatory mechanisms one of these is the control of GnRH synthesis and release. In the past the scarcity of GnRH neurons and their widespread distribution in the brain hindered the study of GnRH gene expression. Until recently the development of GnRH-expressing cell lines with properties similar to those of in vivo GnRH neurons and also transgenic mice facilitated GnRH gene regulation research. This minireview provides a summary of the molecular mechanisms for the control of GnRH-I and GnRH-II gene expression. These include basal transcription regulation which involves essential cis-acting elements in the GnRH-I and GnRH-II promoters and interacting transcription factors and also feedback control by gonadotropins and gonadal sex steroids. Other physiological stimuli e.g. insulin and melatonin will also be discussed. Introduction Gonadotropin-releasing hormone GnRH is a central regulator in the hypothalamic-pituitary-gonadal axis of the reproductive hormonal cascade. It is expressed in a discrete .