Physiological activity

An oestrogen found in the urine of pregnant mares. It is not so physiologically active as equilin. 

Chapters V-X deal respectively with Heterocyclic and Alicyclic Compounds Miscellaneous Reactions Organic Reagents in Inorganic and Organic Chemistry Dyestuffs, Indicators and Related Compounds Some Physiologically-Active Compounds and Synthetic Polymers. Many of these preparations are of course intended for advanced students, but a mere perusal of the experimental details of selected preparations by those whose time for experimental work is limited may assist to impress them on the memory. Attention is particularly directed to the chapter... 

A large number of selenium derivatives such as the selenium analog of vitamin B] have been tested for physiological activity (91). 

Toxicity. Fluoroborates are excreted mostly in the urine (22). Sodium fluoroborate is absorbed almost completely into the human bloodstream and over a 14-d experiment all of the NaBF ingested was found in the urine. Although the fluoride ion is covalently bound to boron, the rate of absorption of the physiologically inert BF from the gastrointestinal tract of rats exceeds that of the physiologically active simple fluorides (23). 

Potassium is required for enzyme activity in a few special cases, the most widely studied example of which is the enzyme pymvate kinase. In plants it is required for protein and starch synthesis. Potassium is also involved in water and nutrient transport within and into the plant, and has a role in photosynthesis. Although sodium and potassium are similar in their inorganic chemical behavior, these ions are different in their physiological activities. In fact, their functions are often mutually antagonistic. For example, increases both the respiration rate in muscle tissue and the rate of protein synthesis, whereas inhibits both processes (42). 

Radiotracers have also been used extensively for the quantitative rnicrodeterrnination of blood semm levels of hormones (qv), proteins, neurotransmitters, and other physiologically important compounds. Radioimmunoassay, which involves the competition of a known quantity of radiolabeled tracer, usually I or H, with the unknown quantity of semm component for binding to a specific antibody that has been raised against the component to be deterrnined, is used in the rnicro deterrnination of physiologically active materials in biological samples (see Immunoassay). 

The reversible oxidation of L-ascorbic acid to dehydro-L-ascorbic acid is the basis for its known physiological activities, stabiUties, and technical apphcations (2). The importance of vitamin C in nutrition and the maintenance of good health is well documented. Over 22,000 references relating only to L-ascorbic acid have appeared since 1966. 

P-Hydroxy steroids which contain the 5,7-diene system and can be activated with uv light to produce vitamin D compounds are called provitamins. The two most important provitamins are ergosterol (1) and 7-dehydrocholesterol (3). They are produced in plants and animals, respectively, and 7-dehydrocholesterol is produced synthetically on a commercial scale. Small amounts of hydroxylated detivatives of the provitamins have been synthesized in efforts to prepare the metaboHtes of vitamin D, but these products do not occur naturally. The provitamins do not possess physiological activities, with the exception that provitamin D is found in the skin of animals and acts as a precursor to vitamin D, and synthetic dihydroxalated... 

Biological functions of Ca(Il) ion are numerous but maybe classified ia one of three categories the formation of soHd skeletal material such as bone, teeth, and shell the stabilizing of proteia conformational stmcture and the most varied, the abiUty of Ca(Il) to trigger certain physiological activities such as muscle contraction and the release of hormones (qv). 

A large number of coumatin derivatives have been identified in plants and many of them have been synthesized and studied for their physiological activity. Only a few are mentioned here because of their economic significance. 

The original commercial source of E was extraction from bovine adrenal glands (5). This was replaced by a synthetic route for E and NE (Eig. 1) similar to the original pubHshed route of synthesis (6). Eriedel-Crafts acylation of catechol [120-80-9] with chloroacetyl chloride yields chloroacetocatechol [99-40-1]. Displacement of the chlorine by methylamine yields the methylamine derivative, adrenalone [99-45-6] which on catalytic reduction yields (+)-epinephrine [329-65-7]. Substitution of ammonia for methylamine in the sequence yields the amino derivative noradrenalone [499-61-6] which on reduction yields (+)-norepinephrine [138-65-8]. The racemic compounds were resolved with (+)-tartaric acid to give the physiologically active (—)-enantiomers. The commercial synthesis of E and related compounds has been reviewed (27). The synthetic route for L-3,4-dihydroxyphenylalanine [59-92-7] (l-DOPA) has been described (28). 

ION-SELECTIVE ELECTRODES REVERSIBLE TO PHYSIOLOGICALLY ACTIVE AMINE CATIONS THE MAIN WAYS FOR CONTROLLING POTENTIOMETRIC SELECTIVITY... 

Despite the fact that a great lot of ion-selective electrodes (ISEs) with liquid and film polymeric membranes for the determination of physiologically active amines (PhAA) has been described, the factors responsible for their selectivity have not yet been studied sufficiently. In this work, the influence of plasticizer and ion-exchanger nature on the selectivity of ISEs reversible to PhAA cations of various stmctures has been discussed. 

DETERMINATION OF SOME PHYSIOLOGICAL ACTIVE COMPONENTS IN PHARMACEUTICAL PRODUCTS BASED ON BISHOFITE... 

---