Gonadotropin Regulation, Oestrogens and the Immune System

Several transmitters and neuropeptides participate in the regulation of gonadotropins. At the hypothalamic level, control of gonadotropin releasing hormone (GnRH) involves noradrenaline, GABA, glutamate, angiotensin II, neuropeptide Y, neurotensin, and 5-hydroxytryptamine as well as interleukins 1 and 2. Ovarian steroids can interfere with gonadotropin regulation by either direct effects on GnRH release or by increasing the sensitivity of anterior pituitary cells to GnRH, thus potentiating the release of pituitary hormones. These interactions involve discrete actions on second messenger systems; similar processes also account for brain and endocrine effects on immune cells.