Biology of the pituitary gonadotrope cell

点击翻译按钮获取中文摘要

The organs of the body, like the brain and heart, are made up of specialized cells that perform the necessary functions of those organs. Our research program is dedicated to more fully understanding the functions of a specific cell type in the pituitary gland called the gonadotrope. The pituitary gland is an organ that sits at the base of the brain. It is comprised of five cell types, each of which makes hormones that control different aspects of bodily function, including reproduction, metabolism, growth, and our responses to stress. ******Hormones are chemical messengers made in one organ that travel through the bloodstream to regulate the activity of other organs. In the case of the reproductive system, pituitary gonadotropes make two hormones called follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Once released from gonadotropes, FSH and LH travel to the ovaries and testicles were they control the development of the eggs and sperm as well as the production of hormones such as testosterone and estrogen. The production and release of FSH and LH, in turn, are controlled by another hormone from the brain called gonadotropin-releasing hormone (GnRH). A major component of our research program is dedicated to understanding how GnRH produces these responses in gonadotrope cells. ******In addition to GnRH, FSH production is strongly controlled by another hormone called activin, which is made by the gonadotrope cell itself; or so we thought. Research findings from our lab suggest that a hormone similar to activin, but not activin itself, may be a primary regulator of FSH production. With the support of this Discovery Grant, we propose to identify this hormone, to determine where it comes from in the body, and to understand how it controls FSH production by gonadotrope cells.******In this grant, we also propose to address a second set of major unanswered questions about gonadotrope cells: How long do they live? Are they replaced continuously, like cells of the hair follicle or intestines, or can they last a life time, like cells of the brain or heart? Can gonadotropes be replaced in adulthood and, if so, from where do they arise? ******Collectively, the knowledge generated from our research program will provide greater insight into the normal workings of pituitary gonadotrope cells specifically and of the reproductive system more generally. At the same time, our results may help us understand what goes awry in some infertile couples.