Neuroendocrine pathways affecting reproduction are
complex withmajor players in the brain, pituitary gland, and
gonads. Hormones secreted into the bloodstream affect the
pathways by binding to receptor molecules expressed on
specialized cells. Characterization of the hormone-receptor
pairs participating in these pathways has led to a better
understanding of reproduction in general and has been
crucial for development of therapies that improve fertility or
approaches that result in contraception. One of the major
players in the neuroendocrine pathways affecting reproduction
is GnRH1. GnRH1 is a small hypothalamic decapeptide
that specifically binds to the GnRH type 1 receptor
(referred from here on as GnRHR). The GnRHR is a member
of the superfamily of G protein-coupled receptors with
seven transmembrane domains [1]. The primary location of
GnRHR is the pituitary gland where the receptors are
restricted to gonadotrope cells [2,3]. ThroughGnRHbinding,
the receptor regulates the synthesis and secretion of pituitary
gonadotropins that are essential for gametogenesis and
synthesis of gonadal steroids.