Characterization of multiple binding sites for /sup 3/H-Estradiol-17. beta. -(. beta. -D-glucuronide) in rat liver plasma membranes: evidence consonant with identification of an organic anion carrier
The binding of /sup 3/H-Estradiol-17..beta..-(..beta..-D-glucuronide) (E/sub 2/17G) was examined in rat liver plasma membranes and two specific binding sites were identified. The evidence for multiplicity is derived from equilibrium, kinetic and inhibition experiments. Displacement and saturation experiments show that /sup 3/H-E/sub 2/17G binding is saturable. The absence of cooperative interactions at either site is suggested by the Hill coefficients (1.15 and 0.95 for Site 1 and Site 2 respectively). Kinetic dissociation experiments show that /sup 3/H-E/sub 2/17G binding is reversible and reveal two components (K/sub -1/'s = 1.4 and 0.024 min/sup -1/) to the dissociation process confirming the existence of multiple sites. The rate of association of /sup 3/H-E/sub 2/17G binding with plasma membranes is very rapid. Na/sup +/ is not required for binding of /sup 3/H-E/sub 2/17G. Ligands which selectively bind to Site 1 have been identified: these are bile acids, ouabain and testosterone glucuronide. The inhibition of /sup 3/H-E/sub 2/17G binding by organic anions provided evidence suggesting that Site 2 represents a hepatic organic anion carrier that is not shared by bile acids.
- Research Organization:
- Kentucky Univ., Lexington (USA)
- OSTI ID:
- 6985771
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANIONS
MEMBRANE TRANSPORT
ESTRADIOL
BIOCHEMICAL REACTION KINETICS
LIVER
PLASMA CELLS
ORGANIC COMPOUNDS
BILE ACIDS
CELL MEMBRANES
EXPERIMENTAL DATA
GLUCURONIDE CONJUGATES
INHIBITION
LIGANDS
OUABAIN
RATS
TESTOSTERONE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANDROGENS
ANDROSTANES
ANIMAL CELLS
ANIMALS
BODY
CARBOHYDRATES
CARBOXYLIC ACIDS
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CHARGED PARTICLES
CONNECTIVE TISSUE CELLS
DATA
DIGESTIVE SYSTEM
DRUGS
ESTRANES
ESTROGENS
GLANDS
GLYCOSIDES
HORMONES
HYDROXY COMPOUNDS
INFORMATION
IONS
ISOTOPE APPLICATIONS
KETONES
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
METABOLITES
NUMERICAL DATA
ORGANIC ACIDS
ORGANS
REACTION KINETICS
RODENTS
SOMATIC CELLS
STEROID HORMONES
STEROIDS
STEROLS
STROPHANTHINS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques