Radioimmunoassay and metabolism of the catechol estrogen 2-hydroxyestradiol
Plasma levels of 2-hydroxyestradiol (2-OHE/sub 2/) were measured using a new RIA procedure. Values were below the detection limit of the assay (<10 pg/ml), except in the third trimester of pregnancy, when they rose to approximately 15 pg/ml. The infusion of 130 ..mu..g/h purified 2-OHE/sub 2/ elevated its plasma concentration to 155 pg/ml, consistent with a plasma MCR (MCR/sub p) of approximately 20,000 liters/day. The infusion of (/sup 3/H)2-OHE/sub 2/ to equilibrium and chromatographic separation of the extracted plasma metabolites yielded an MCR/sub p/ of about 13,000 liters/day; the major plasma metabolite comigrated with 2-methoxyestradiol, and (/sup 3/H)delta-methoxyestrone was also formed. The MCR/sub p/ of 2-OHE/sub 2/ is approximately half that of 2-hydroxyestrone (2-OHE)/sub 1/), but much higher than those of other steroids. As is true for 2-OHE/sub 1/ the clearance of 2-OHE/sub 2/ must occur primarily in the blood compartment. Together, the measured MCR/sub p/ values and estrogen receptor affinities of 2-OHE/sub 2/ and 2-OHE/sub 1/ predict a relative potency for effects upon gonadotropin secretion which is close to that observed in vivo.
- Research Organization:
- National Institutes of Health, Bethesda, MD
- OSTI ID:
- 5800531
- Journal Information:
- J. Clin. Endocrinol. Metab.; (United States), Journal Name: J. Clin. Endocrinol. Metab.; (United States) Vol. 54:1; ISSN JCEMA
- Country of Publication:
- United States
- Language:
- English
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550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD PLASMA
BODY FLUIDS
DATA
ESTRADIOL
ESTRANES
ESTROGENS
EXPERIMENTAL DATA
HORMONES
HYDROXY COMPOUNDS
HYDROXYL RADICALS
IN VITRO
INFORMATION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MATERIALS
METABOLISM
METABOLITES
NUMERICAL DATA
ORGANIC COMPOUNDS
RADICALS
RADIOASSAY
RADIOIMMUNOASSAY
REACTION KINETICS
STEROID HORMONES
STEROIDS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
UPTAKE