Radioimmunoassay for 2-Methoxyoestrone in Human Plasma

Abstract

A bovine serum albumin conjugate of 2-methoxyoestrone was used for the preparation of highly specific antibodies in rabbits. Cross-reactivity for catecholoestrogens and monophenolic steroids was below 0.3 %. Only 2-methoxyoestradiol cross-reacted with 44 %. An assay procedure for the determination of unconjugated and conjugated 2-methoxyoestrone in human plasma is described. The following mean plasma concentrations (pg/ml) were found (unconjugated/conjugated): children 61/1130, young men 74/1320, elderly men 109/1260, cycling women 131/1040, post-menopausal women 102/1420, and pregnant women 3980/5850.

Concentrations of 2-methoxyoestrogens in human serum measured by a heterologous immunoassay with an 125I-labelled ligand

“…The radioimmunological method described hitherto utilizes tritium labelled radioligands, with high specific radioactivities not yet available com¬ mercially (Emons et al 1979).…”

“…The radioimmunological method described hitherto utilizes tritium labelled radioligands, with high specific radioactivities not yet available com¬ mercially (Emons et al 1979). Regarding the in¬ creasing problems of waste disposal of 3H-radioactivity and organic solvents including the high cost we preferred the use of 125I-labelled radioligands.…”

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Abstract1

. Therefore in addition to the measurement of 2-hydroxyoestrogens (Berg et al 1982) the 2-methoxyoestrogens should be meas¬ ured for a sufficient description of the production and excretion rates of 2-substituted oestrogens.The radioimmunological method described hitherto utilizes tritium labelled radioligands, with high specific radioactivities not yet available com¬ mercially (Emons et al 1979).

Antibodies raised against 2-methoxyoestradiol-17\g=b\-hemi-succinyl-BSA served as binding protein and 2-methoxyoestrone -17cmo -[125I]iodohistamine served as 125I-labelled ligand.…”

Hypocholesterolemic Effect of Long-Term Continuous Administration of 2-Methoxyestriol in Dietary Hypercholesterolemic Rats

“…As for catecholestrogen 2-monomethyl ethers, the daily urinary excretion of 2-methoxyestrone in late pregnancy was 145-1,150 (450) 1u g [17] ; and that of 2-(and 3-)-McOE3, 50-250 ,u g [18,19], being considerably lower than that of classic estrogen. In contrast, the blood level of unconjugated 2-methoxyestrone was equivalent to, or slightly lower than the classic estrogen level; 180 pg/ml in the ovulatory phase, 100-150 pg/ml in the follicular and luteal phases, and 3.98 ng/ml during the 21st 30th weeks of gestation [18,19]. These findings indicate that catecholestrogen 2-monomethyl ethers have important physiological roles in lipid metabolism, as does classic estrogen.…”

“…The blood concentrations of unconj ugated 2-hydroxyestrone and 2-hydroxyestradiol, which had been thought to be considerably high, were recently found to be considerably low, 1/5-1/20 of the classic estrogen level in both non-pregnant and pregnant women [15,16]. As for catecholestrogen 2-monomethyl ethers, the daily urinary excretion of 2-methoxyestrone in late pregnancy was 145-1,150 (450) 1u g [17] ; and that of 2-(and 3-)-McOE3, 50-250 ,u g [18,19], being considerably lower than that of classic estrogen. In contrast, the blood level of unconjugated 2-methoxyestrone was equivalent to, or slightly lower than the classic estrogen level; 180 pg/ml in the ovulatory phase, 100-150 pg/ml in the follicular and luteal phases, and 3.98 ng/ml during the 21st 30th weeks of gestation [18,19].…”