arginine

DEFINITION:

An amino acid produced by the hydrolysis or digestion of proteins.

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).

AVP

DEFINITION:

Arginine vasopressin.

water reabsorption

DEFINITION:

1. The act or process of absorbing water again.

2. Resorption.

renal 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.

principal cells

DEFINITION:

1. The fundamental cells of an organ, which usually have a specific function.

2. The principal cells are the chief cells, i.e., the most abundant cells of the parathyroid glands, being polygonal epithelial cells with a granular cytoplasm and vesicular nuclei, arranged in plates or cords, and which are rich in glycogen: the clear cells are more numerous and have relatively large nuclei and clear cytoplasm with few granules, while the dark cells are smaller with smaller and darker nuclei and finely granular cytoplasm with many granules. Intermediate forms also exist.

activation

DEFINITION:

1. The act or process of rendering active.

2. The transformation of a proenzyme into an active enzyme by the action of a kinase or another proenzyme.

3. Gain in the purifying of sewage by means of activated sludge.

4. The process by which the central nervous system is stimulated into activity through the mediation of the reticular activating system.

5. The deliberate induction of a pattern of electrical activity in the brain in electroencephalography.

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).

V2

DEFINITION:

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

receptors

DEFINITION:

See definitions under "receptor."

subsequent

DEFINITION:

Following after; succeeding.

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.

water channels

DEFINITION:

Channels in a cell membrane that permit passage of water molecules; chemical substances such as vasopressin cause the opening of new channels and increase permeability.

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.

intracellular vesicles

DEFINITION:

Vesicles within a cell.

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.

prostaglandin

DEFINITION:

Any of a group of components derived from unsaturated 20-carbon fatty acids, primarily arachidonic acid, via the cyclooxygenase pathway; they are potent mediators of numerous different physiologic processes. The abbreviation for prostaglandin is PG; specific compounds are designated by adding a letter to indicate the type of ring structure and a numerical subscript to indicate the number of double bonds in the hydrocarbon skeleton (e.g., PGE₂, etc.). Most naturally occurring prostaglandins have two double bonds and are synthesized from arachidonic acid. The 1 series and 3 series are produced by the same pathway starting with fatty acids that have one fewer or one more double bond than arachidonic acid. The subscript a or ß indicates the three-dimensional configuration of alcoholic groups attached to the ring structures (a denotes a substituent below the plane of the ring, ß, above the plane). The naturally occurring PGF's all have the a configuration. Prostaglandins act in the cells in which they are synthesized and surrounding cells, and their actions and effects vary with concentration, hormonal environment, and cell type.

AVP

DEFINITION:

Arginine vasopressin.

water reabsorption

DEFINITION:

1. The act or process of absorbing water again.

2. Resorption.

signaling

DEFINITION:

A molecule or chemical which cues a responsive behavior in its surrounding environment.

pathway

DEFINITION:

1. A path or course, especially a course followed in the attainment of a specific end.
2. The nerve structures through which an impulse passes between groups of nerve cells or between the central nervous system and an organ or muscle.
3. Metabolic pathway.

inner medullary collecting duct

DEFINITION:

The distal part of the renal tubule, including the loop of Henle, lying within the medulla.

IMCD

DEFINITION:

Inner medullary collecting duct.

cells

DEFINITION:

See definitions for "cell."

activation

DEFINITION:

1. The act or process of rendering active.

2. The transformation of a proenzyme into an active enzyme by the action of a kinase or another proenzyme.

3. Gain in the purifying of sewage by means of activated sludge.

4. The process by which the central nervous system is stimulated into activity through the mediation of the reticular activating system.

5. The deliberate induction of a pattern of electrical activity in the brain in electroencephalography.

actin

DEFINITION:

A protein of the myofibril, localized in the I band; acting along with myosin particles, it is responsible for the contraction and relaxation of muscle. In the absence of salt, it becomes globular (G-actin), and in the presence of potassium chloride and adenosine triphosphate it polymerizes, forming long fibers (F-actin).

polymerization

DEFINITION:

The act or process of forming a compound (polymer), usually of high molecular weight, by the combination of simpler molecules.

IMCD cells

DEFINITION:

Inner medullary collecting duct (IMCD) cells.

intracellular

DEFINITION:

Situated or occurring within a cell or cells.

localization

DEFINITION:

1. The determination of the site or place of any process or lesion.
2. Restriction to a circumscribed or limited area.
3. Prelocalization.

AQP2

DEFINITION:

Aquaporin-2.

AVP

DEFINITION:

Arginine vasopressin.

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.

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.

cAMP

DEFINITION:

Cyclic AMP (cyclic adenosine monophosphate).

receptors

DEFINITION:

See definitions under "receptor."

AVP

DEFINITION:

Arginine vasopressin.

inactivation

DEFINITION:

1. The destruction of biological activity, as of a virus or enzyme, by the action of heat or other physical or chemical means.

2. The act of making inactive.

AVP

DEFINITION:

Arginine vasopressin.

F-actin

DEFINITION:

The long-fiber form of actin .

depolymerization

DEFINITION:

The conversion of a polymer into its component monomers.

signaling

DEFINITION:

A molecule or chemical which cues a responsive behavior in its surrounding environment.

pathway

DEFINITION:

1. A path or course, especially a course followed in the attainment of a specific end.
2. The nerve structures through which an impulse passes between groups of nerve cells or between the central nervous system and an organ or muscle.
3. Metabolic pathway.

diuretic

DEFINITION:

1. Increasing the excretion of urine.

2. An agent that promotes the excretion of urine.

diuretic

DEFINITION:

1. Increasing the excretion of urine.

2. An agent that promotes the excretion of urine.

cAMP

DEFINITION:

Cyclic AMP (cyclic adenosine monophosphate).

activation

DEFINITION:

1. The act or process of rendering active.

2. The transformation of a proenzyme into an active enzyme by the action of a kinase or another proenzyme.

3. Gain in the purifying of sewage by means of activated sludge.

4. The process by which the central nervous system is stimulated into activity through the mediation of the reticular activating system.

5. The deliberate induction of a pattern of electrical activity in the brain in electroencephalography.

F-actin

DEFINITION:

The long-fiber form of actin .

formation

DEFINITION:

1. The process of giving shape or form; the creation of an entity, or of a structure of definite shape.

2. A structure of definite shape.

permission

DEFINITION:

Formal consent; authorization.