Gonadotropin-releasing hormone family
Encyclopedia
The gonadotropin-releasing hormones (GnRH) (gonadoliberin) are a family of peptides that play a pivotal role in reproduction. The main function of GnRH is to act on the pituitary to stimulate the synthesis and secretion of luteinizing and follicle-stimulating hormone
s, but GnRH also acts on the brain
, retina
, sympathetic nervous system
, gonads, and placenta
in certain species. There seems to be at least three forms of GnRH. The second form is expressed in midbrain and seems to be widespread. The third form has been found so far only in fish. GnRH is a C-terminal amidated decapeptide processed from a larger precursor protein. Four of the ten residues are perfectly conserved in all species where GnRH has been sequenced.
Follicle-stimulating hormone
Follicle-stimulating hormone is a hormone found in humans and other animals. It is synthesized and secreted by gonadotrophs of the anterior pituitary gland. FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. FSH and Luteinizing hormone act...
s, but GnRH also acts on the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
, retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
, sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
, gonads, and placenta
Placenta
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...
in certain species. There seems to be at least three forms of GnRH. The second form is expressed in midbrain and seems to be widespread. The third form has been found so far only in fish. GnRH is a C-terminal amidated decapeptide processed from a larger precursor protein. Four of the ten residues are perfectly conserved in all species where GnRH has been sequenced.