protein

DEFINITION:

Any of a group of complex organic compounds which contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur, the characteristic element being nitrogen, and which are widely distributed in plants and animals. Proteins, the principal constituents of the protoplasm of all cells, are of high molecular weight and consist essentially of combinations of a-amino acids in peptide linkages. Twenty different amino acids are commonly found in proteins, and each protein has a unique, genetically defined amino acid sequence which determines its specific shape and function. They serve as enzymes, structural elements, hormones, immunoglobulins, etc., and are involved in oxygen transport, muscle contraction, electron transport, and other activities throughout the body, and in photosynthesis.

binding protein - any of a number of plasma proteins (See below) that bind to hormones of low solubility (chiefly the thyroid and steroid hormones), thus providing a transport system for them; some are specific for particular hormones, while others bind to any sparingly soluble hormones. Called also carrier protein or transport protein (See below).

carrier proteins - A binding protein (See above).

plasma proteins - The hundreds of different proteins present in blood plasma, including carrier proteins (such as albumin, transferrin, and haptoglobin), fibrinogen and other coagulation factors, complement components, immunoglobulins, enzyme inhibitors, precursors of substances such as angiotensin and bradykinin, and many other types of proteins.

transport protein - binding protein (See above).

protein

DEFINITION:

Any of a group of complex organic compounds which contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur, the characteristic element being nitrogen, and which are widely distributed in plants and animals. Proteins, the principal constituents of the protoplasm of all cells, are of high molecular weight and consist essentially of combinations of a-amino acids in peptide linkages. Twenty different amino acids are commonly found in proteins, and each protein has a unique, genetically defined amino acid sequence which determines its specific shape and function. They serve as enzymes, structural elements, hormones, immunoglobulins, etc., and are involved in oxygen transport, muscle contraction, electron transport, and other activities throughout the body, and in photosynthesis.

binding protein - any of a number of plasma proteins (See below) that bind to hormones of low solubility (chiefly the thyroid and steroid hormones), thus providing a transport system for them; some are specific for particular hormones, while others bind to any sparingly soluble hormones. Called also carrier protein or transport protein (See below).

carrier proteins - A binding protein (See above).

plasma proteins - The hundreds of different proteins present in blood plasma, including carrier proteins (such as albumin, transferrin, and haptoglobin), fibrinogen and other coagulation factors, complement components, immunoglobulins, enzyme inhibitors, precursors of substances such as angiotensin and bradykinin, and many other types of proteins.

transport protein - binding protein (See above).

diabetes insipidus

DEFINITION:

A disorder of the pituitary gland characterized by intense thirst and by the excretion of large amounts of urine.

diabetes insipidus, central - A metabolic disorder due to injury of the neurohypophyseal system, which results in a deficient quantity of antidiuretic hormone being released or produced, and thus in failure of tubular reabsorption of water in the kidney. As a result, a large amount of urine of low specific gravity is excreted, followed by dehydration and great thirst; it is often attended by voracious appetite, loss of strength, and emaciation. It may be inherited, acquired, or idiopathic.

diabetes insipidus, nephrogenic - 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.

diabetes insipidus, pituitary - Central diabetes insipidus (See above).

protein

DEFINITION:

Any of a group of complex organic compounds which contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur, the characteristic element being nitrogen, and which are widely distributed in plants and animals. Proteins, the principal constituents of the protoplasm of all cells, are of high molecular weight and consist essentially of combinations of a-amino acids in peptide linkages. Twenty different amino acids are commonly found in proteins, and each protein has a unique, genetically defined amino acid sequence which determines its specific shape and function. They serve as enzymes, structural elements, hormones, immunoglobulins, etc., and are involved in oxygen transport, muscle contraction, electron transport, and other activities throughout the body, and in photosynthesis.

binding protein - any of a number of plasma proteins (See below) that bind to hormones of low solubility (chiefly the thyroid and steroid hormones), thus providing a transport system for them; some are specific for particular hormones, while others bind to any sparingly soluble hormones. Called also carrier protein or transport protein (See below).

carrier proteins - A binding protein (See above).

plasma proteins - The hundreds of different proteins present in blood plasma, including carrier proteins (such as albumin, transferrin, and haptoglobin), fibrinogen and other coagulation factors, complement components, immunoglobulins, enzyme inhibitors, precursors of substances such as angiotensin and bradykinin, and many other types of proteins.

transport protein - binding protein (See above).

growth

DEFINITION:

1. A normal process of increase in size of an organism as a result of accretion of tissue similar to that originally present.

2. An abnormal formation, such as a tumor.

3. The proliferation of cells, as in a bacterial culture.