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.

AQP-2

DEFINITION:

Aquaporin-2.

encodes

DEFINITION:

Converts (a message, information, etc.) into code.

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 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.

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.

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.

urinary excretion

DEFINITION:

The throwing off or elimination of urine by normal discharge.

AQP-2

DEFINITION:

Aquaporin-2.

radioimmunoassay

DEFINITION:

A highly sensitive and specific assay method that uses the competition between radiolabeled and unlabeled substances in an antigen-antibody reaction to determine the concentration of the unlabeled substance; it can be used to determine antibody concentrations or to determine the concentration of any substance against which specific antibody can be produced. Abbreviated RIA.

preterm

DEFINITION:

That which occurs prior to a definite period or specified time of duration, such as the premature culmination of pregnancy at less than 40 weeks from the last menstrual period or 38 weeks from conception.

molecular

DEFINITION:

Of, pertaining to, or composed of molecules.

water balance

DEFINITION:

Fluid balance.

AQP-2

DEFINITION:

Aquaporin-2.

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.

preterm

DEFINITION:

That which occurs prior to a definite period or specified time of duration, such as the premature culmination of pregnancy at less than 40 weeks from the last menstrual period or 38 weeks from conception.

AQP-2

DEFINITION:

Aquaporin-2.

urinary excretion

DEFINITION:

The throwing off or elimination of urine by normal discharge.

AQP-2

DEFINITION:

Aquaporin-2.

postnatally

DEFINITION:

Occurring after birth, with reference to the newborn.

urine osmolality

DEFINITION:

The concentration of osmotically active particles in solution (in this case, urine) expressed in terms of osmoles of solute per kilogram of solvent. The osmolality is directly proportional to the colligative properties of solutions: osmotic pressure, boiling point elevation, freezing point depression, and vapor pressure lowering.

arginine vasopressin

DEFINITION:

Vasopressin containing arginine, as that from most mammals, including man.

AVP

DEFINITION:

Arginine vasopressin.

urinary

DEFINITION:

Pertaining to the urine; containing or secreting urine.

AQP-2

DEFINITION:

Aquaporin-2.

correlated

DEFINITION:

See correlation.

urine osmolality

DEFINITION:

The concentration of osmotically active particles in solution (in this case, urine) expressed in terms of osmoles of solute per kilogram of solvent. The osmolality is directly proportional to the colligative properties of solutions: osmotic pressure, boiling point elevation, freezing point depression, and vapor pressure lowering.

AVP

DEFINITION:

Arginine vasopressin.

AQP-2

DEFINITION:

Aquaporin-2.

preterm

DEFINITION:

That which occurs prior to a definite period or specified time of duration, such as the premature culmination of pregnancy at less than 40 weeks from the last menstrual period or 38 weeks from conception.

vasopressin-regulated water channels

DEFINITION:

Water flows in and out of cells throughout the body except in some places in the kidneys. Cells shrink in hypotonic environments (places where there is too little water) and swell in hypertonic environments (places where there is too much water). Ideally fluid inside the cells (intracellular fluid--ICF) should be the same tonicity (contain the same concentration of water) as fluid outside the cells (extracellular fluid--ECF). To regulate this balance, some cells "sense" the concentration of water outside of them and send out the appropriate amount of antidiuretic hormone (ADH) or arginine vasopressin (AVP) to keep the correct amount of water in the blood. The AVP initiates a series of actions which results in water channel proteins being sent to cells which need more water. Once the water channel proteins are in place, the cell absorbs the water it needs. When the correct balance between ECF and ICF has been restored, the water channel proteins are removed from the cell membrane. (Source: DP - JTRAN-3)

expressed

DEFINITION:

1. Showing a detectable effect of a gene.

2. Made known; shown.

3. Squeezed out; extracted by pressing.

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.

preterm

DEFINITION:

That which occurs prior to a definite period or specified time of duration, such as the premature culmination of pregnancy at less than 40 weeks from the last menstrual period or 38 weeks from conception.

encoded

DEFINITION:

Converted (a message, information, etc.) into code.

AQP-2

DEFINITION:

Aquaporin-2.

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.

concentrating

DEFINITION:

1. Bringing to a common center; gathering together at one point.

2. Increasing the strength by diminishing the bulk of, as of a liquid; condensing.

3. The strengthening of a drug or other preparation by the evaporation of its non-active parts.

power

DEFINITION:

1. Capability; potency; the ability to act.
2. A measure of magnification, as of a microscope.
3. The rate at which work is done. Symbol P. The SI unit of power is the watt.
4. Of a statistical test: the probability of correctly rejecting the null hypothesis when a specified alternative holds true; it is equal to 1 minus the probability of a Type II error.

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.