Biomaterial Database

Modulation of myo-[3H]inositol uptake by glucose and sorbitol in cultured bovine lens epithelial cells. II. Characterization of high- and low-affinity myo-inositol transport sites. 1992

P R Cammarata, and H Q Chen, and J Yang, and T Yorio

Department of Anatomy and Cell Biology, Texas College of Osteopathic Medicine/University of North Texas, Fort Worth 76107.

Myo-[3H]inositol accumulation in cultured bovine lens epithelial cells (BLECs) occurred by high- and low-affinity, Na(+)-dependent transport sites. The high- and low-affinity transport systems had a Km of 27 +/- 4 and 157 +/- 22 mumol/l, respectively, and Vmax of 652 +/- 35 and 2952 +/- 308 pmol/mg protein/hr, respectively. The uptake of myo-[3H]inositol was lowered after chronic (20 hr) incubation of cultured cells in 40 mmol/l glucose throughout the concentration range for 1.5-400 mumol/l myo-inositol. The coadministration of sorbinil (0.1 mmol/l) to 40 mmol/l glucose partially prevented the inhibitory effect of glucose on myo-[3H]inositol uptake. Although the aldose reductase inhibitor prevented the inhibitory effect of glucose on the low-affinity transport site, a glucose-sensitive process for myo-[3H]inositol uptake on the high-affinity transport site was uncovered by Lineweaver-Burk analysis. Acute exposure (3 hr) of cultured BLECs maintained in physiologic medium (Eagle's minimal essential medium, 5.5 mmol/l glucose) to a range of 5.5-44 mmol/l glucose plus sorbinil also caused a decrease in myo-[3H]inositol uptake. Dixon plot analysis confirmed that the acute effect of glucose was the result of competitive inhibition of the high-affinity myo-inositol transport site. Acute exposure of cultured cells to 10-40 mmol/l sorbitol also diminished the accumulation of myo-[3H]inositol. Dixon plot analysis established that the acute effect of exogenous sorbitol was the result of competitive inhibition of the low-affinity myo-inositol transport site.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007093	Imidazoles	Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).
D007294	Inositol	An isomer of glucose that has traditionally been considered to be a B vitamin although it has an uncertain status as a vitamin and a deficiency syndrome has not been identified in man. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1379) Inositol phospholipids are important in signal transduction.	Myoinositol,Chiro-Inositol,Mesoinositol,Chiro Inositol
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D007908	Lens, Crystalline	A transparent, biconvex structure of the EYE, enclosed in a capsule and situated behind the IRIS and in front of the vitreous humor (VITREOUS BODY). It is slightly overlapped at its margin by the ciliary processes. Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.	Eye Lens,Lens, Eye,Crystalline Lens
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D004848	Epithelium	The layers of EPITHELIAL CELLS which cover the inner and outer surfaces of the cutaneous, mucus, and serous tissues and glands of the body.	Mesothelium,Epithelial Tissue,Mesothelial Tissue,Epithelial Tissues,Mesothelial Tissues,Tissue, Epithelial,Tissue, Mesothelial,Tissues, Epithelial,Tissues, Mesothelial
D005947	Glucose	A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.	Dextrose,Anhydrous Dextrose,D-Glucose,Glucose Monohydrate,Glucose, (DL)-Isomer,Glucose, (alpha-D)-Isomer,Glucose, (beta-D)-Isomer,D Glucose,Dextrose, Anhydrous,Monohydrate, Glucose
D000449	Aldehyde Reductase	An enzyme that catalyzes reversibly the oxidation of an aldose to an alditol. It possesses broad specificity for many aldoses. EC 1.1.1.21.	Aldose Reductase,Aldose Reductase Ia,Aldose Reductase Ib,Erythrose Reductase,Xylose Reductase,Reductase Ia, Aldose,Reductase Ib, Aldose,Reductase, Aldehyde,Reductase, Aldose,Reductase, Erythrose,Reductase, Xylose
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia