The manufacture and release by a cell, gland, or organ of substances, (such as enzymes) needed for metabolic processes elsewhere in the body.
The term applied to the material formed by a GLAND as the result of its activity. For example, saliva is the secretion of the salivary glands; gastric juice that of the glands in the stomach wall; bile that of the liver. Some secretions consist apparently of waste material which is of no further use in the chemistry of the body. These secretions are often spoken of as excretions: for example, the URINE and the sweat – see PERSPIRATION. (For further details, see ENDOCRINE GLANDS, and also under the headings of the various organs.)
n. 1. the process by which a gland isolates constituents of the blood or tissue fluid and chemically alters them to produce a substance that it discharges for use by the body or excretes. The principal methods of secretion – *apocrine, *holocrine, and *merocrine – are illustrated in the diagram. 2. the substance that is produced by a gland.
(SIADH) a condition of inappropriately high plasma levels of ADH (see vasopressin) with associated water retention, dilutional *hyponatraemia, and the production of highly concentrated urine. Renal, adrenal, thyroid, and hepatic function are normal, as is the volume of circulating blood (euvolaemia). It is caused by a variety of pathological conditions, usually intrathoracic and intracerebral, and also by a number of drugs, including antidepressants, chemotherapy agents, and some of the older antidiabetic agents. The treatment involves fluid restriction, treatment (or removal) of the underlying cause (or drug), and, in severe cases, administration of *demeclocycline to reduce the effects of ADH on the kidney. Very rarely, hypertonic saline is given.... syndrome of inappropriate secretion of antidiuretic hormone
Health Encyclopedia