Biomaterial Database

Specific binding sites for natural glucocorticoids in plasma membranes of rat liver. 1975

T Suyemitsu, and H Terayama

The presence of sites specifically binding natural glucocortocoids in plasma membrane (PM) preparations (PM0, density=1.13-1.16; PM1, density=1.16-1.18) from rat liver was elucidated by equilibrium dialysis as well as by centrifugal methods. Equilibrium dialysis showed the presence of binding sites having a higher affinity for [3-H]cortisol (Kd=1.4 times 10- minus 9M at 4C) in PM0, and that of the binding sites having a lower affinity for [3H] cortisol (Kd=1.3 times 10- minus 8M at 4C) in PM1, while centrifugal analysis showed the presence of higher affinity binding sites (Kd=1.5-1.9 times 10- minus 97 at 0 C) in both PM0 and PM1, and also of intermediate affinity binding sites (Kd=4.1 times 10- minus 9M at 0 C) in PM1. The discrepancy in the cortisol binding parameters obtained by the two different methods seems to be due mainly to the lability of some binding sites, especially the PM1. The glucocorticoid-binding sites in the plasma membranes of rat liver appear to have the highest affinity of corticosterone, followed by cortisol and cortisone. A synthetic glucocorticoid [3H]-dexamethasone, did not show any specific binding to the liver plasma membranes. Neither dexamethasone nor nonglucocorticoids such as estradiol given simultaneously affected [3H] cortisol binding to the plasma membranes.

UI	MeSH Term	Description	Entries
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D008861	Microsomes	Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Microsome
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D009928	Organ Specificity	Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.	Tissue Specificity,Organ Specificities,Specificities, Organ,Specificities, Tissue,Specificity, Organ,Specificity, Tissue,Tissue Specificities
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols