The Development of Kisspeptin Circuits in the Mammalian Brain - Kisspeptin Signaling in Reproductive Biology - page 215

Chapter 11
The Development of Kisspeptin Circuits
in the Mammalian Brain
Sheila J. Semaan , Kristen P. Tolson , and Alexander S. Kauffman
Abstract The neuropeptide kisspeptin, encoded by the Kiss1 gene, is required for
mammalian puberty and fertility. Examining the development of the kisspeptin sys-
tem contributes to our understanding of pubertal progression and adult reproduction
and sheds light on possible mechanisms underlying the development of reproduc-
tive disorders, such as precocious puberty or hypogonadotropic hypogonadism.
Recent work, primarily in rodent models, has begun to study the development of
kisspeptin neurons and their regulation by sex steroids and other factors at early life
stages. In the brain, kisspeptin is predominantly expressed in two areas of the hypo-
thalamus, the anteroventral periventricular nucleus and neighboring periventricular
nucleus (pre-optic area in some species) and the arcuate nucleus. Kisspeptin neu-
rons in these two hypothalamic regions are differentially regulated by testosterone
and estradiol, both in development and in adulthood, and also display differences in
their degree of sexual dimorphism. In this chapter, we discuss what is currently
known and not known about the ontogeny, maturation, and sexual differentiation of
kisspeptin neurons, as well as their regulation by sex steroids and other factors dur-
ing development.
Introduction
The status of the neuroendocrine reproductive axis is in fl ux during various stages of
perinatal and pubertal development, ranging from being entirely quiescent to fully
active. Additionally, the neuroendocrine reproductive system is anatomically and
physiologically differentiated between males and females, and these sex differences
S. J. Semaan • K. P. Tolson • A. S. Kauffman , Ph.D. ( * )
Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive,
0674, Leichtag Building, Room 3A-15, La Jolla, CA 92093 , USA
e-mail: [e-mail] ; [e-mail]; [e-mail]