inositol

views updated Jun 11 2018

inositol A cyclic alcohol, C6H12O6, that is a constituent of certain cell phosphoglycerides; the most important isomer is myo-inositol (see formula). It is sometimes classified as a member of the vitamin B complex but it can be synthesized by many animals and it is not regarded as an essential nutrient in humans. Phosphatidylinositol, a constituent of plasma membranes, is a precursor of the intracellular second messenger molecules, inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG); these are produced, through the mediation of phospholipase C, in response to the binding of a substance, e.g. serotonin, to receptors on the cell surface. They mediate such cellular events as smooth muscle contraction, adrenaline secretion, and histamine secretion.

inositol

views updated Jun 27 2018

inositol A carbohydrate derivative, a constituent of phospholipids (phosphatidyl inositols) involved in membrane structure and as part of the signalling mechanism for hormones which act at the cell surface. It is an essential nutrient for micro‐organisms and some animals, although there is no evidence that it is a dietary essential for human beings. Obsolete names are inosite and meat sugar.

The insecticide gammexane is hexachlorocyclohexane, and appears to function by competing with inositol. The hexaphosphate ester of inositol is phytic acid.

inositol

views updated Jun 11 2018

inositol A carbocyclic or sugar alcohol, widely distributed in both plants and animals. It is a constituent of membranes, muscles, and nervous tissue and is necessary for growth. Inositol is often classed with the B vitamins as it has been reported to be essential in the diets of some organisms.

inositol

views updated Jun 27 2018

inositol (in-oh-sit-ol) n. a compound, similar to a hexose sugar, that is a constituent of some cell phospholipids; it is present in the bran of cereal grain. It is sometimes classified as a vitamin but it can be synthesized by most animals and there is no evidence that it is an essential nutrient in humans.

inositol

views updated May 21 2018

inositol A carbocyclic or sugar alcohol (C6H12O6) that is widely distributed in both plants and animals. It is often classed with the B vitamins, as it has been reported to be essential in the diets of some organisms.