molecular

DEFINITION:

Of, pertaining to, or composed of molecules.

nephrogenic diabetes insipidus

DEFINITION:

A syndrome of polyuria and hyposthenuria caused by the failure of the renal tubules to reabsorb water in response to antidiuretic hormone, without disturbance in the renal filtration and solute excretion rates; the condition does not respond to exogenous vasopressin. It may be inherited as a rare X-linked trait or be acquired as a result of drug therapy or systemic disease.

collecting duct

DEFINITION:

See under duct.

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).

abnormalities

DEFINITION:

1. The quality or fact of being abnormal.


2. Malformations, deformities, or anomalies.

mediate

DEFINITION:

Indirect; accomplished by the aid of an intervening medium.

principal cell

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.

hydraulic

DEFINITION:

1. Operated, moved, or effected by means of water.

2. Of or relating to hydraulics.

3. Operated by the resistance offered or the pressure transmitted when a quantity of liquid is forced through a small orifice or through a tube.

4. Hardening or setting under water.

conductivity

DEFINITION:

The capacity of a body to transmit a flow of electricity or heat; it is the conductance per unit area of the body. When expressed in figures electrical conductivity is the reciprocal of resistivity.

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 .

genetic

DEFINITION:

1. Relating to or determined by the origin, development, or causal antecedents of something.

2. Of, relating to, or being a gene.

nephrogenic diabetes insipidus

DEFINITION:

A syndrome of polyuria and hyposthenuria caused by the failure of the renal tubules to reabsorb water in response to antidiuretic hormone, without disturbance in the renal filtration and solute excretion rates; the condition does not respond to exogenous vasopressin. It may be inherited as a rare X-linked trait or be acquired as a result of drug therapy or systemic disease.

affect

DEFINITION:

1. To produce an effect on; influence.

2. The external expression of emotion attached to ideas or mental representations of objects.

binding

DEFINITION:

1. Wrapping with a binder or bandage.

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

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 receptor

DEFINITION:

See under receptor .

subsequent

DEFINITION:

Following after; succeeding.

intracellular

DEFINITION:

Situated or occurring within a cell or cells.

signaling

DEFINITION:

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

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.

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.

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.

apical membrane

DEFINITION:

See under membrane.

genetic

DEFINITION:

1. Relating to or determined by the origin, development, or causal antecedents of something.

2. Of, relating to, or being a gene.

duct

DEFINITION:

A passage with well-defined walls, especially a tube for the passage of excretions or secretions.

Bellini's duct - See papillary duct below.

collecting duct - Renal collecting tubule: the arcuate renal tubule, straight collecting tubule, and papillary duct considered together.

papillary duct - A wide terminal tubule in the renal pyramid, formed by the union of several straight collecting tubules and emptying into the renal pelvis in the area cribrosa. Called also Bellini's duct or tubule.

absorption

DEFINITION:

1. The uptake of substances into or across tissues, e.g., skin, intestine, and kidney tubules.


2. In radiology, the taking up of energy by matter with which the radiation interacts.

diminishing

DEFINITION:

Making or causing to seem smaller, less, less important, etc.; lessening, reducing, or decreasing.

interstitial

DEFINITION:

Pertaining to or situated between parts or in the interspaces of a tissue.

medullary

DEFINITION:

Pertaining to the marrow or to any medulla; resembling marrow.

osmolarity

DEFINITION:

The concentration of an osmotic solution especially when measured in osmols or milliosmols per liter of solution.

permission

DEFINITION:

Formal consent; authorization.