aquaporin-2

DEFINITION:

Also called WCH-CD, this water channel makes the principal cells of the inner medullary collecting duct in the kidneys more permeable to water. Lack of functional aquaporin-2 gene leads to a rare form of nephrogenic diabetes insipidus.

AQP2

DEFINITION:

Aquaporin-2.

vasopressin

DEFINITION:

1. One of two octapeptide hormones formed by the neuronal cells of the hypothalamic nuclei and stored in the posterior lobe of the pituitary gland (neurohypophysis), the other being oxytocin. It stimulates the contraction of the muscular tissue of the capillaries and arterioles, raising the blood pressure. It promotes contraction of the intestinal musculature and increases peristalsis, and also exerts some contractile influence on the uterus. It also has a specific effect on the epithelial cells of the distal portion of the uriniferous tubule, augmenting resorption of water independently of solutes, resulting in concentration of urine and dilution of blood serum. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.

2. [USP], A pharmaceutical preparation of the same principle, prepared synthetically or obtained from the posterior pituitary of healthy domestic animals used for food by man; used mainly as an antidiuretic in the treatment of acute or chronic diabetes insipidus, administered intramuscularly as a test of hypothalamo-neurohypophysial-renal function in distinguishing central from nephrogenic diabetes insipidus; it may also be used to stimulate smooth muscle tissue, especially to induce vasoconstriction in the presence of hemorrhage. Called also antidiuretic hormone (ADH).

regulated

DEFINITION:

1. Having been adjusted to a certain standard.

2. In biology, describing the adaptation of form or behavior of an organism to changed conditions.

water channel

DEFINITION:

A channel in the plasma membrane of plant and animal cells that permits passage of water molecules; chemical substances such as vasopressin cause the opening of new channels and increase permeability.

kidney collecting duct

DEFINITION:

Also known as the tubulus renalis colligens , or renal collecting tubule: that structure of the kidney consisting of the arcuate renal tubule, straight collecting tubule, and papillary duct considered together.

regulation

DEFINITION:

1. The act of adjusting or state or being adjusted to a certain standard.
2. In biology, the adaptation of form or behavior of an organism to changed conditions.
3. The power to form a whole embryo from stages before the gastrula.

body water balance

DEFINITION:

See fluid balance.

regulation

DEFINITION:

1. The act of adjusting or state or being adjusted to a certain standard.
2. In biology, the adaptation of form or behavior of an organism to changed conditions.
3. The power to form a whole embryo from stages before the gastrula.

vasopressin

DEFINITION:

1. One of two octapeptide hormones formed by the neuronal cells of the hypothalamic nuclei and stored in the posterior lobe of the pituitary gland (neurohypophysis), the other being oxytocin. It stimulates the contraction of the muscular tissue of the capillaries and arterioles, raising the blood pressure. It promotes contraction of the intestinal musculature and increases peristalsis, and also exerts some contractile influence on the uterus. It also has a specific effect on the epithelial cells of the distal portion of the uriniferous tubule, augmenting resorption of water independently of solutes, resulting in concentration of urine and dilution of blood serum. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.

2. [USP], A pharmaceutical preparation of the same principle, prepared synthetically or obtained from the posterior pituitary of healthy domestic animals used for food by man; used mainly as an antidiuretic in the treatment of acute or chronic diabetes insipidus, administered intramuscularly as a test of hypothalamo-neurohypophysial-renal function in distinguishing central from nephrogenic diabetes insipidus; it may also be used to stimulate smooth muscle tissue, especially to induce vasoconstriction in the presence of hemorrhage. Called also antidiuretic hormone (ADH).

binds

DEFINITION:

1. To wrap with a binder or bandage.

2. To form a weak, reversible chemical bond, e.g., antigen to antibody or hormone to receptor.

basolateral

DEFINITION:

Pertaining to the base and the sides.

V2

DEFINITION:

Vasopressin-2. See vasopressin-2 gene and vasopressin-2 receptor.

cAMP

DEFINITION:

Cyclic AMP (cyclic adenosine monophosphate).

protein kinase A

DEFINITION:

Cyclic AMP-dependent protein kinase. Protein kinase A is a necessary part of the molecular cascade that results in AQP2 insertion into the apical membrane. (JC)

phosphorylation

DEFINITION:

The metabolic process of introducing a phosphate group into an organic molecule.

AQP2

DEFINITION:

Aquaporin-2.

translocation

DEFINITION:

A structural chromosome aberration in which one segment of a chromosome is transferred to a nonhomologous chromosome, the result of breakage of both chromosomes with repair in abnormal arrangement.

AQP2

DEFINITION:

Aquaporin-2.

apical plasma membrane

DEFINITION:

Indicating the apex of the plasma membrane.

osmotic water permeability

DEFINITION:

The ability to channel water across a membrane in response to a concentration gradient.

vasopressin

DEFINITION:

1. One of two octapeptide hormones formed by the neuronal cells of the hypothalamic nuclei and stored in the posterior lobe of the pituitary gland (neurohypophysis), the other being oxytocin. It stimulates the contraction of the muscular tissue of the capillaries and arterioles, raising the blood pressure. It promotes contraction of the intestinal musculature and increases peristalsis, and also exerts some contractile influence on the uterus. It also has a specific effect on the epithelial cells of the distal portion of the uriniferous tubule, augmenting resorption of water independently of solutes, resulting in concentration of urine and dilution of blood serum. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.

2. [USP], A pharmaceutical preparation of the same principle, prepared synthetically or obtained from the posterior pituitary of healthy domestic animals used for food by man; used mainly as an antidiuretic in the treatment of acute or chronic diabetes insipidus, administered intramuscularly as a test of hypothalamo-neurohypophysial-renal function in distinguishing central from nephrogenic diabetes insipidus; it may also be used to stimulate smooth muscle tissue, especially to induce vasoconstriction in the presence of hemorrhage. Called also antidiuretic hormone (ADH).

AQP2

DEFINITION:

Aquaporin-2.

osmotic water permeability

DEFINITION:

The ability to channel water across a membrane in response to a concentration gradient.

regulation

DEFINITION:

1. The act of adjusting or state or being adjusted to a certain standard.
2. In biology, the adaptation of form or behavior of an organism to changed conditions.
3. The power to form a whole embryo from stages before the gastrula.

AQP2

DEFINITION:

Aquaporin-2.

endocytosis

DEFINITION:

The uptake by a cell of material from the environment by invagination (infolding) of its plasma membrane; it includes both phagocytosis and pinocytosis.

kidney

DEFINITION:

One of a pair of vertebrate organs situated in the body cavity near the spinal column that excrete waste products of metabolism, in man are bean-shaped organs about 4-1/2 inches long lying behind the peritoneum in a mass of fatty tissue, and consist chiefly of nephrons by which urine is secreted, collected, and discharged into a main cavity whence it is conveyed by the ureter to the bladder.

cells

DEFINITION:

See definitions for "cell."

cells

DEFINITION:

See definitions for "cell."

AQP2

DEFINITION:

Aquaporin-2.

wt-AQP2

DEFINITION:

Wild-type AQP2.

AQP2

DEFINITION:

Aquaporin-2.

mutated

DEFINITION:

1. Changed in form, quality, or some other characteristic.
2. In genetics, having undergone a permanent transmissible change in the genetic material, usually in a single gene. Also, an individual exhibiting such a change.

site

DEFINITION:

A place, position, or locus.

mimic

DEFINITION:

1. Mimetic, i.e., marked by stimulation of another bodily process or disease.

phosphorylated

DEFINITION:

See phosphorylation.

phosphorylated

DEFINITION:

See phosphorylation.

AQP2

DEFINITION:

Aquaporin-2.

AQP2

DEFINITION:

Aquaporin-2.

wt-AQP2

DEFINITION:

Wild-type AQP2.

cAMP

DEFINITION:

Cyclic AMP (cyclic adenosine monophosphate).

agent

DEFINITION:

Any power, principle, or substance capable of producing an effect, whether physical, chemical, or biological.

forskolin

DEFINITION:

Activator of adenylate cyclase leading to an increase in the intracellular concentration of cAMP.

(Sources: A. Laurenza, et al., Trends Pharm. Sci. 10: 442-447 (1989) and R. Barber and T.J. Goka, J. Cyclic Nucleotide Protein Phos. Res. 10:23-29 (1985) @www.lclabs.com/PROFILE/D-F/F-9929.php4.)

translocation

DEFINITION:

A structural chromosome aberration in which one segment of a chromosome is transferred to a nonhomologous chromosome, the result of breakage of both chromosomes with repair in abnormal arrangement.

wt-AQP2

DEFINITION:

Wild-type AQP2.

forskolin

DEFINITION:

Activator of adenylate cyclase leading to an increase in the intracellular concentration of cAMP.

(Sources: A. Laurenza, et al., Trends Pharm. Sci. 10: 442-447 (1989) and R. Barber and T.J. Goka, J. Cyclic Nucleotide Protein Phos. Res. 10:23-29 (1985) @www.lclabs.com/PROFILE/D-F/F-9929.php4.)

cells

DEFINITION:

See definitions for "cell."

protein kinase C

DEFINITION:

Any of a family of protein kinase isozymes, occurring in numerous tissues, that catalyze the phosphorylation of specific serine or threonine residues of a variety of intracellular proteins, altering their activities. The enzymes are activated via receptor binding by the hormones, growth factors, and other agents that cause increases in intracellular calcium and cleavage of phosphoinositides; some isozymes require calcium and phospholipid for activity, which is enhanced by diacylglycerol. The enzyme is involved in several types of cellular signal transduction and has been shown to play a role in platelet activation and in the inhibition of some peptide hormone receptors and to be a binding site for phorbol esters and other tumor promoters, as well as having numerous other roles and substrates, only some of which are known.

PKC

DEFINITION:

Protein kinase C.

phorbol

DEFINITION:

A polycyclic alcohol occurring naturally in croton oil; it is the parent compound of the phorbol esters.

acetate

DEFINITION:

A salt or ester or the conjugate base of acetic acid.

wt-AQP2

DEFINITION:

Wild-type AQP2.

plasma membrane

DEFINITION:

The structure enveloping a cell, enclosing the cytoplasm, and forming a selective permeability barrier; it consists of lipids, proteins, and some carbohydrates, the lipids thought to form a bilayer in which integral proteins are embedded to varying degrees.

intracellular vesicles

DEFINITION:

Vesicles within a cell.

forskolin

DEFINITION:

Activator of adenylate cyclase leading to an increase in the intracellular concentration of cAMP.

(Sources: A. Laurenza, et al., Trends Pharm. Sci. 10: 442-447 (1989) and R. Barber and T.J. Goka, J. Cyclic Nucleotide Protein Phos. Res. 10:23-29 (1985) @www.lclabs.com/PROFILE/D-F/F-9929.php4.)

endocytosis

DEFINITION:

The uptake by a cell of material from the environment by invagination (infolding) of its plasma membrane; it includes both phagocytosis and pinocytosis.

AQP2

DEFINITION:

Aquaporin-2.

intracellular

DEFINITION:

Situated or occurring within a cell or cells.

forskolin

DEFINITION:

Activator of adenylate cyclase leading to an increase in the intracellular concentration of cAMP.

(Sources: A. Laurenza, et al., Trends Pharm. Sci. 10: 442-447 (1989) and R. Barber and T.J. Goka, J. Cyclic Nucleotide Protein Phos. Res. 10:23-29 (1985) @www.lclabs.com/PROFILE/D-F/F-9929.php4.)

AQP2

DEFINITION:

Aquaporin-2.

endocytosis

DEFINITION:

The uptake by a cell of material from the environment by invagination (infolding) of its plasma membrane; it includes both phagocytosis and pinocytosis.

mediated

DEFINITION:

Accomplished by the aid of an intervening medium.

PKC

DEFINITION:

Protein kinase C.

PKC

DEFINITION:

Protein kinase C.

regulation

DEFINITION:

1. The act of adjusting or state or being adjusted to a certain standard.
2. In biology, the adaptation of form or behavior of an organism to changed conditions.
3. The power to form a whole embryo from stages before the gastrula.

AQP2

DEFINITION:

Aquaporin-2.

endocytosis

DEFINITION:

The uptake by a cell of material from the environment by invagination (infolding) of its plasma membrane; it includes both phagocytosis and pinocytosis.

membrane

DEFINITION:

A thin layer of tissue which covers a surface, lines a cavity, or divides a space or organ.

apical membrane - Pertaining to or located at the apex.

basolateral membrane - Pertaining to the base and sides.

plasma membrane - The structure enveloping a cell, enclosing the cytoplasm, and forming a selective permeability barrier; it consists of lipids, proteins, and some carbohydrates, the lipids thought to form a bilayer in which integral proteins are embedded to varying degrees.

postsynaptic membrane - The area of plasma membrane of a postsynaptic cell, either a muscle fiber or a neuron, that is within the synapse and has areas especially adapted for receiving neurotransmitters.

presynaptic membrane - Area of the plasma membrane of a presynaptic axon that is within the synapse and has sites (active zones) especially adapted for the release of neurotransmitters.

semipermeable membrane - A membrane that permits the passage of a solvent, such as water, but prevents the passage of the dissolved substance, or solute.

intracellular vesicles

DEFINITION:

Vesicles within a cell.

cells

DEFINITION:

See definitions for "cell."

hormone

DEFINITION:

A product of living cells that circulates in body fluids and produces a specific effect on the activity of cells remote from its point of origin; especially: one exerting a stimulatory effect on a cellular activity.

hypophysiotropic hormones - Hormones produced by the hypothalamus, usually releasing hormones (see below), which maintain the endocrine functions of cells of the adenohypophysis.

neurohormone - A hormone secreted by a specialized neuron into the bloodstream, the cerebrospinal fluid, or the intercellular spaces of the nervous system.

releasing hormones - Hormones elaborated in one structure that cause the release of hormones from another structure, such as those from the hypothalamus that act on the adenohypophysis. The term is applied to substances of established chemical identity, whereas substances of unknown chemical structure are called releasing factors .

vasopressin

DEFINITION:

1. One of two octapeptide hormones formed by the neuronal cells of the hypothalamic nuclei and stored in the posterior lobe of the pituitary gland (neurohypophysis), the other being oxytocin. It stimulates the contraction of the muscular tissue of the capillaries and arterioles, raising the blood pressure. It promotes contraction of the intestinal musculature and increases peristalsis, and also exerts some contractile influence on the uterus. It also has a specific effect on the epithelial cells of the distal portion of the uriniferous tubule, augmenting resorption of water independently of solutes, resulting in concentration of urine and dilution of blood serum. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.

2. [USP], A pharmaceutical preparation of the same principle, prepared synthetically or obtained from the posterior pituitary of healthy domestic animals used for food by man; used mainly as an antidiuretic in the treatment of acute or chronic diabetes insipidus, administered intramuscularly as a test of hypothalamo-neurohypophysial-renal function in distinguishing central from nephrogenic diabetes insipidus; it may also be used to stimulate smooth muscle tissue, especially to induce vasoconstriction in the presence of hemorrhage. Called also antidiuretic hormone (ADH).

VP

DEFINITION:

Abbreviation for vasopressin.

molecular sequence

DEFINITION:

See definition 3 under sequence.

kidney collecting duct cells

DEFINITION:

Kidney collecting duct cells are cells which are mainly located in the medulla of the kidney. In the kidney, the blood fluid is filtered into tubules (nephrons) where electrolytes, water, and many other components are reabsorbed or even secreted. Collecting duct cells are at the end of such nephrons. Here, water is reabsorbed from the urine, and therefore, urine becomes concentrated. Reabsorption of water in collecting duct cells is regulated by the V2 vasopressin receptor. Inactivating mutations of V2 vasopressin receptor result in a loss of water reabsorption in collecting duct cells—the cause of nephrogenic diabetes insipidus (Schöneberg).

aquaporin-2

DEFINITION:

Also called WCH-CD, this water channel makes the principal cells of the inner medullary collecting duct in the kidneys more permeable to water. Lack of functional aquaporin-2 gene leads to a rare form of nephrogenic diabetes insipidus.

AQP2

DEFINITION:

Aquaporin-2.

cell

DEFINITION:

1. Any one of the minute protoplasmic masses that make up organized tissue, consisting of a nucleus which is surrounded by cytoplasm which contains the various organelles and is enclosed in the cell or plasma membrane. A cell is the fundamental, structural, and functional unit of living organisms.

2. A small, more or less closed space.

neuroglial cells - The cells of the supportive tissue of the central nervous system (neuroglia); these non-neural cells are of three kinds: astrocytes, oligodendrocytes (collectively termed macroglia) and microglia.

reticular cells - The cells forming the reticular fibers of connective tissue; those forming the framework of lymph nodes, bone marrow, and spleen are part of the reticuloendothelial system and under appropriate stimulation may differentiate into macrophages.

stem cell - 1. Any precursor cell.

2. A blood cell progenitor, or mother cell, having the capacity for both replication and differentiation, and giving rise to various morphologically recognizable precursors of different blood cell lines, such as the proerythrocyte and myeloblast, which cannot self-replicate and must differentiate into more mature daughter cells.

cell membrane

DEFINITION:

Plasma membrane.

concentration

DEFINITION:

1. Increase in strength by evaporation.

2. The ratio of the mass or volume of a solute to the mass or volume of the solution or solvent.

urine

DEFINITION:

The fluid excreted by the kidneys, passed through the ureters, stored in the bladder, and discharged through the urethra. Urine, in health, has an amber color, a slight acid reaction, a peculiar odor, and a bitter, saline taste.

VP

DEFINITION:

Abbreviation for vasopressin.

AQP2

DEFINITION:

Aquaporin-2.

membrane

DEFINITION:

A thin layer of tissue which covers a surface, lines a cavity, or divides a space or organ.

apical membrane - Pertaining to or located at the apex.

basolateral membrane - Pertaining to the base and sides.

plasma membrane - The structure enveloping a cell, enclosing the cytoplasm, and forming a selective permeability barrier; it consists of lipids, proteins, and some carbohydrates, the lipids thought to form a bilayer in which integral proteins are embedded to varying degrees.

postsynaptic membrane - The area of plasma membrane of a postsynaptic cell, either a muscle fiber or a neuron, that is within the synapse and has areas especially adapted for receiving neurotransmitters.

presynaptic membrane - Area of the plasma membrane of a presynaptic axon that is within the synapse and has sites (active zones) especially adapted for the release of neurotransmitters.

semipermeable membrane - A membrane that permits the passage of a solvent, such as water, but prevents the passage of the dissolved substance, or solute.

cell

DEFINITION:

1. Any one of the minute protoplasmic masses that make up organized tissue, consisting of a nucleus which is surrounded by cytoplasm which contains the various organelles and is enclosed in the cell or plasma membrane. A cell is the fundamental, structural, and functional unit of living organisms.

2. A small, more or less closed space.

neuroglial cells - The cells of the supportive tissue of the central nervous system (neuroglia); these non-neural cells are of three kinds: astrocytes, oligodendrocytes (collectively termed macroglia) and microglia.

reticular cells - The cells forming the reticular fibers of connective tissue; those forming the framework of lymph nodes, bone marrow, and spleen are part of the reticuloendothelial system and under appropriate stimulation may differentiate into macrophages.

stem cell - 1. Any precursor cell.

2. A blood cell progenitor, or mother cell, having the capacity for both replication and differentiation, and giving rise to various morphologically recognizable precursors of different blood cell lines, such as the proerythrocyte and myeloblast, which cannot self-replicate and must differentiate into more mature daughter cells.

endocytosis

DEFINITION:

The uptake by a cell of material from the environment by invagination (infolding) of its plasma membrane; it includes both phagocytosis and pinocytosis.

AQP2

DEFINITION:

Aquaporin-2.

cell

DEFINITION:

1. Any one of the minute protoplasmic masses that make up organized tissue, consisting of a nucleus which is surrounded by cytoplasm which contains the various organelles and is enclosed in the cell or plasma membrane. A cell is the fundamental, structural, and functional unit of living organisms.

2. A small, more or less closed space.

neuroglial cells - The cells of the supportive tissue of the central nervous system (neuroglia); these non-neural cells are of three kinds: astrocytes, oligodendrocytes (collectively termed macroglia) and microglia.

reticular cells - The cells forming the reticular fibers of connective tissue; those forming the framework of lymph nodes, bone marrow, and spleen are part of the reticuloendothelial system and under appropriate stimulation may differentiate into macrophages.

stem cell - 1. Any precursor cell.

2. A blood cell progenitor, or mother cell, having the capacity for both replication and differentiation, and giving rise to various morphologically recognizable precursors of different blood cell lines, such as the proerythrocyte and myeloblast, which cannot self-replicate and must differentiate into more mature daughter cells.

analysis

DEFINITION:

1. Separation into component parts or elements; the act of determining the component parts of a substance.

2. Psychoanalysis.

VP

DEFINITION:

Abbreviation for vasopressin.

sequence

DEFINITION:

1. A connected series of events or things.
2. In dysmorphology, a pattern of multiple anomalies derived from a single known or presumed prior anomaly or mechanical factor.
3. In molecular biology, often used to refer to DNA having a particular nucleotide composition or occurring in a particular region of the genome.

cell cultures

DEFINITION:

The maintenance or growth of animal cells in vitro, or a culture of such cells.

cellular

DEFINITION:

Pertaining to, or made up of, cells.

compound

DEFINITION:

1. In chemistry, a substance that consists of two or more chemical elements in union.

2. In genetics, a genotype in which there are two different mutant alleles at a locus, or a phenotype produced by such a genotype.

3. A word consisting of parts that are already words.

protein kinase C

DEFINITION:

Any of a family of protein kinase isozymes, occurring in numerous tissues, that catalyze the phosphorylation of specific serine or threonine residues of a variety of intracellular proteins, altering their activities. The enzymes are activated via receptor binding by the hormones, growth factors, and other agents that cause increases in intracellular calcium and cleavage of phosphoinositides; some isozymes require calcium and phospholipid for activity, which is enhanced by diacylglycerol. The enzyme is involved in several types of cellular signal transduction and has been shown to play a role in platelet activation and in the inhibition of some peptide hormone receptors and to be a binding site for phorbol esters and other tumor promoters, as well as having numerous other roles and substrates, only some of which are known.

PKC

DEFINITION:

Protein kinase C.

AQP2

DEFINITION:

Aquaporin-2.

endocytosis

DEFINITION:

The uptake by a cell of material from the environment by invagination (infolding) of its plasma membrane; it includes both phagocytosis and pinocytosis.