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.

mediated

DEFINITION:

Accomplished by the aid of an intervening medium.

EP

DEFINITION:

Abbreviation for "evoked potential."

receptors

DEFINITION:

See definitions under "receptor."

in vivo

DEFINITION:

Within the living body.

gene targeting

DEFINITION:

A process by which precise alterations may be made in the mammalian genome, using the ability of tissue culture cells to induce homologous recombination between introduced DNA molecules and their own genomes.

obvious

DEFINITION:

Easily found, seen, or understood.

abnormalities

DEFINITION:

1. The quality or fact of being abnormal.


2. Malformations, deformities, or anomalies.

organ

DEFINITION:

A somewhat independent part of the body that performs a special function or functions.

effector organ - An organ that produces an effect, e.g., contraction or secretion, in response to nerve stimulation.

expressed

DEFINITION:

1. Showing a detectable effect of a gene.

2. Made known; shown.

3. Squeezed out; extracted by pressing.

renal medulla

DEFINITION:

The inner part of the substance of the kidney, composed chiefly of collecting tubule elements, loops of Henle, and vasa recta, organized grossly into pyramids.

cortical collecting duct

DEFINITION:

Also known as the "cortical collecting tubule," the more proximal parts of the renal tubule, lying within the cortex.

antagonize

DEFINITION:

1. To act in direct opposition.

2. To nullify; i.e., the action of a substance that tends to nullify the action of another, as a drug that binds to a cell receptor without eliciting a biological response, blocking binding or substances that could elicit such responses.

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).

distal nephron

DEFINITION:

See nephron.

urinary

DEFINITION:

Pertaining to the urine; containing or secreting urine.

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.

basal

DEFINITION:

Pertaining to or situated near a base.

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.

wild-type

DEFINITION:

In genetics, the standard phenotype for any experimental organism; also a gene that determines a standard phenotypic trait. See also under gene .

inhibition

DEFINITION:

Arrest or restraint of a process.

endogenous

DEFINITION:

1. Growing from within.

2. Developing or originating within the organism, or arising from causes within the organism.

indomethacin

DEFINITION:

A nonsteroidal anti-inflammatory agent; used in the treatment of rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, and acute gouty arthritis.

inhibition

DEFINITION:

Arrest or restraint of a process.

concentrated

DEFINITION:

1. Brought to a common center; gathered together at one point.

2. Having increased the strength by diminishing the bulk of, as of a liquid; condensed.

3. A drug or other preparation that has been strengthened by the evaporation of its non-active parts.

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.

series

DEFINITION:

1. A group or succession of objects or substances arranged in regular order or forming a kind of chain.
2. Pertaining to electrical circuit components connected "in series" so that the current flow goes through each component without branching; applied by extension to any similar series circuit, e.g., the pulmonary and systemic circulations.
3. A taxonomic category of fungi falling between a subphylum and an order and based on the type of ascus the organism possesses.

monocytic series - The succession of developing cells that ultimately culminates in the monocyte; after the colony-forming unit-granulocyte-macrophage , the stages in order of maturity are the monoblast , promonocyte , and the mature monocyte .

physiological

DEFINITION:

1. Of or pertaining to physiology.
2. Characteristic of or appropriate to an organism's healthy or normal functioning.
3. Differing in, involving, or affecting physiological factors.

stimuli

DEFINITION:

Plural of stimulus .

modulate

DEFINITION:

See modulation .

urinary

DEFINITION:

Pertaining to the urine; containing or secreting urine.

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.

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.

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.

urinary 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.

permission

DEFINITION:

Formal consent; authorization.