Neurophysins
Encyclopedia
Neurophysins are carrier protein
s which transport the hormones oxytocin
and vasopressin
to the posterior pituitary
from the paraventricular
and supraoptic nucleus
of the hypothalamus
. Neurophysins are secreted from the posterior lobe of the pituitary along with their passenger hormones, though their physiological roles are unknown.
There are two types:
Carrier protein
Carrier proteins are proteins involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane. Carrier proteins are integral membrane proteins; that is they exist within and span the membrane across which they transport substances. The...
s which transport the hormones oxytocin
Oxytocin
Oxytocin is a mammalian hormone that acts primarily as a neuromodulator in the brain.Oxytocin is best known for its roles in sexual reproduction, in particular during and after childbirth...
and vasopressin
Vasopressin
Arginine vasopressin , also known as vasopressin, argipressin or antidiuretic hormone , is a neurohypophysial hormone found in most mammals, including humans. Vasopressin is a peptide hormone that controls the reabsorption of molecules in the tubules of the kidneys by affecting the tissue's...
to the posterior pituitary
Posterior pituitary
The posterior pituitary comprises the posterior lobe of the pituitary gland and is part of the endocrine system. Despite its name, the posterior pituitary gland is not a gland, per se; rather, it is largely a collection of axonal projections from the hypothalamus that terminate behind the anterior...
from the paraventricular
Paraventricular nucleus
The paraventricular nucleus is a neuronal nucleus in the hypothalamus. It contains multiple subpopulations of neurons that are activated by a variety of stressful and/or physiological changes. Many PVN neurons project directly to the posterior pituitary where they release oxytocin or vasopressin...
and supraoptic nucleus
Supraoptic nucleus
The supraoptic nucleus is a nucleus of magnocellular neurosecretory cells in the hypothalamus of the mammalian brain. The nucleus is situated at the base of the brain, adjacent to the optic chiasm...
of the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
. Neurophysins are secreted from the posterior lobe of the pituitary along with their passenger hormones, though their physiological roles are unknown.
There are two types:
- Neurophysin INeurophysin INeurophysin I is a carrier protein with a size of 10 KDa and containing 90 to 97 aminoacids that is a cleavage product of preprooxyphysin...
- oxytocinOxytocinOxytocin is a mammalian hormone that acts primarily as a neuromodulator in the brain.Oxytocin is best known for its roles in sexual reproduction, in particular during and after childbirth... - Neurophysin IINeurophysin IINeurophysin II is a carrier protein which binds vasopressin. It is generated from the same precursor as vasopressin.It can be associated with neurohypophyseal diabetes insipidus.Neurophysin II is also known as a stimulator of Prolactin secretion....
- vasopressinVasopressinArginine vasopressin , also known as vasopressin, argipressin or antidiuretic hormone , is a neurohypophysial hormone found in most mammals, including humans. Vasopressin is a peptide hormone that controls the reabsorption of molecules in the tubules of the kidneys by affecting the tissue's...