A novel radioimmunoassay of allopregnanolone.

A radioimmunoassay for determination of 3 alpha-hydroxy-5 alpha-pregnan-20-one (allopregnanolone) in serum or plasma has been developed and evaluated. The method employs rabbit antiserum to 3 alpha-hydroxy-5 alpha-pregnane-11,20-dione-11-O-carboxymethyloxime bovine serum-albumin conjugate and tritiated radioligand. The main cross-reactant interfering in the assay, progesterone, is eliminated by permanganate oxidation. Two assay variants were compared, with and without a micro-column chromatography. The simplified variant appeared to be reliable enough for determination of allopregnanolone in normally menstruating women at luteal phase, whereas the column-chromatography step is necessary when analyzing samples of expected low analyte concentration as in women in follicular phase, postmenopausal women, or in men. The levels of allopregnanolone in healthy women correlated excellently with progesterone in agreement with previous findings.

Pharmacological effects of 2- and 4-methyloestradiol as a probe to test the biological importance of 2- and 4-hydroxylation of oestrogens (catecholoestrogen-formation).

2-Methyloestradiol, 4-hydroxy-2-methyloestradiol and 4-methyloestradiol were synthesized and infused sc into long-term ovariectomized rats by means of osmotic minipumps. The effects on uterine growth and gonadotrophin release were tested and compared to oestradiol or vehicle alone. 2-Methyloestradiol and 4-hydroxy-2-methyloestradiol, steroids in which the 2-hydroxylation is selectively blocked, definitely increased uterine weight (dry and wet), decreased morning LH and increased evening LH serum levels. 4-Methyloestradiol, a compound which cannot be 4-hydroxylated in vivo, was inactive in the model used. It is assumed that 4-hydroxylation constitutes an essential step in the expression of oestrogenicity of primary oestrogens, whereas 2-hydroxylation does not.

Radioimmunoassay for 4-hydroxyestrone 4-methyl ether in human urine.

4-Hydroxyestrone 4-methyl ether (4-OHE1 4-Me) was converted to its 17-(O-carboxymethyl)oxime and then coupled to bovine serum albumin. The injection of this steroid-protein conjugate into rabbits induced the formation of antibodies with high specificity and affinity for 4-OHE1 4-Me. With this antiserum a radioimmunoassay was developed which allowed the measurement of 4-OHE1 4-Me with a lower limit of detection of 6 pg/tube. Using a simple and practicable method for the hydrolysis and purification of urine, the excretion rates of 4-OHE1 4-Me were reliably measured in healthy human subjects: male children 0.1 microgram/24 h, female children 0.2 micrograms/24 h, men (20-45 years) 0.7 micrograms/24 h, men (greater than 50 years) 0.5 micrograms/24 h, women, follic. 0.5 micrograms/24 h, periov. 0.6 micrograms/24 h, luteal 0.6 micrograms/24 h, women pregn., first trim. 2.3 micrograms/24 h, sec. trim. 2.9 micrograms/24 h, third trim. 5 micrograms/24 h, women postmenop. 0.5 micrograms/24 h. These urinary excretion rates of 4-OHE1 4-Me are significantly lower than those of 4-hydroxyestrone. Comparing the ratios 4-OHE1 4-Me/4-hydroxyestrone with those of 2-hydroxyestrone 2-methyl ether/2-hydroxyestrone, it becomes obvious that endogenous 4-hydroxyestrogens are methylated in vivo to a much lesser extent than the isomeric 2-hydroxyestrogens, a finding which could partly explain why 4-hydroxyestrogens have higher biologic potencies than their 2-hydroxylated isomers

Synthesis of [2H8] estradiol, [2H7] estrone, [2H6] 2-hydroxyestrone and [2H6] 4-hydroxyestrone as internal standards for selected ion monitoring.

The synthesis of [2H8] estradiol, [2H7] estrone, [2H6] 2-hydroxyestrone and [2H6] 4-hydroxyestrone from estrone (as a source) is described. The high isotopical purity renders the labelled compounds as suitable carriers and internal standards for quantitative gas chromatography - mass spectrometry. The content of protonium-form (i.e. natural) estrogens in the labelled derivatives ranged from 0.12% to 2.58%. The performance of these compounds in quantitative assays using selected ion monitoring has been established; and this allows the determination of estrogens from biological material in the lower picogram range.

Synthesis of pyrogallolestrogens (2,3,4-trihydroxy-1,3,5(10)-estratrienes) and their methyl ethers.

The preparation of 2,4-dihydroxyestrone, 2,4-dihydroxyestradiol-17beta and their methyl ethers (14 compounds) is described. The structures were established by nuclear magnetic resonance, infrared and mass spectra as well as by elemental analyses, microchemical reactions, alternative synthetic routes and by their chromatographic properties.

[Metabolism of retro-progesterone and 17-hydroxy-retro-progesterone]. / Untersuchungen über den Stoffwechsel von retro-Progesteron und 17-Hydroxy-reto-Progesteron

In comparative studes, the metabolism of retro-progesterone (9 beta,10alpha-pregn-4-ene-3, 20-dinoe) and 17-hydrozy-retro-progesterone (17-hydroxy-9 beta, 10 alpha-prgn-4-ene-3, 20-dione) as well as of progesterone and 17-hydroxy progesterone was investigated. The microsomal fraction from rat tests served as enzmye preparation. Whereas progesterone was metablised to 17-hydroxy-progesterone, testosterone and androstendion, retno-progesterone did not yield the corresponding reaction products. 16 alpha-Hydroxy-retro progresterone was found to be the main metabolite of retro-progesterone and identified by gas-liquid chromatopgray/mass spectrometry. In contrast to 17-hydroxy-progesterone, no transformation of 17-hudroxy-retro-progesterone to C19-steriods was observed. From these experiments, it can beconcluded that C21 -retro-steriods are not attacked by the 17alpha-hydrozylase and the C17-C20-desmolase of mammalian origin.

The isolation of 6-alpha-hydroxyoestrone from the urine of pregnant women.

1. In view of previous experiments in vitro and in vivo, in which 6-hydroxylation of phenolic steroids by various tissues was demonstrated, an attempt was made to isolate 6-hydroxy oestrogens from the urine of pregnant women. 2. During this work it was found that free 6alpha- as well as 6beta-hydroxylated oestrogens were extremely unstable under acidic conditions (pH <3); it was therefore necessary to establish experimental conditions under which no rearrangement of the hydroxyl group would take place. 3. By avoiding acid steps during the experimental procedures, a ketonic-phenolic fraction was obtained from enzymically hydrolysed late-pregnancy urine that was subjected to paper chromatography in various systems. 4. By using similar methods on a large scale and partition chromatography on Celite columns, a crystalline material was obtained from 1001. of late-pregnancy urine that was identified as 6alpha-hydroxyoestrone by various chemical reactions and by infrared spectroscopy.