High-affinity binding of (/sup 3/H)estradiol-17 beta by an estrogen receptor in the liver of the turtle

Journal Article · Wed Jun 01 00:00:00 EDT 1988 · Gen. Comp. Endocrinol.; (United States)

DOI:https://doi.org/10.1016/0016-6480(88)90112-8· OSTI ID:6736318

Ho, S M; Fehrer, S; Yu, M; Liang, L C; Press, D

Specific (3H)estradiol-17 beta ((3H)E2) binding activity (EBA) with characteristics of an estrogen receptor (ER) was demonstrated in cytosols and nuclear extracts of the female turtle, Chrysemys picta. Three different receptor assays (dextran-coated charcoal assay, hydroxylapatite batch procedure, and DNA-cellulose chromatography) were evaluated in terms of their applicability in analyzing large numbers of samples. For the measurement of cytosolic EBA, the hydroxylapatite batch procedure was found to be the most reliable assay. On the other hand, the dextran-coated charcoal assay was found to be the most appropriate method for the measurement of nuclear EBA. Turtle hepatic EBA binds (3H)E2 with high affinity (cytosolic, 17.4 +/- 2.8 X 10(9) M-1; nuclear, 17.7 +/- 1.9 X 10(9) M-1), limited capacity (cytosolic, 133.7 +/- 4.6 fmol/g tissue; nuclear, 81.1 +/- 9.0 fmol/g tissue), and strict steroid specificity. The EBA bound natural estrogens (E2, estrone, estriol) as well as the nonsteroidal estrogen, diethylstilbestrol, but exhibited little affinity for androgens, progesterone, or corticosterone. The turtle hepatic EBA resembled mammalian and avian ERs in terms of binding characteristics; however, unlike mammalian and avian ERs it was shown to be heat-labile. Incubation at 30 degrees caused rapid loss of (3H)E2 binding activity in both cytosolic and nuclear fractions. The exchange between (3H)E2 and the endogenously bound estrogen was slow at 4 and 15 degrees, but the exchange process was facilitated in the presence of the chaotropic salt, NaSCN. Establishment of quantitation methods for both cytosolic and nuclear forms of EBA will enable future investigation of the mechanism and regulation of estrogen action in the liver of this turtle species.

• Research Organization: Tufts Univ., Medford, MA (USA)
• OSTI ID: 6736318
• Journal Information: Gen. Comp. Endocrinol.; (United States), Vol. 70:3
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ESTRADIOL
BIOCHEMICAL REACTION KINETICS
ESTROGENS
RECEPTORS
AFFINITY
BIOASSAY
LIGANDS
LIVER
THIOCYANATES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TURTLES
ANIMALS
ANTITHYROID DRUGS
BODY
CARBONIC ACID DERIVATIVES
DIGESTIVE SYSTEM
DRUGS
ESTRANES
GLANDS
HORMONE ANTAGONISTS
HORMONES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MEMBRANE PROTEINS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PROTEINS
REACTION KINETICS
REPTILES
STEROID HORMONES
STEROIDS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques