Radioimmunoassay system for norethisterone using 3H- and 125I-labelled radioligands.
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A mixture of 2-3H and 4-14C-mestranol was administered orally to five women and 2-3H-mestranol alone to one woman. Reactions involving position 2 were extensive as judged by liberation of 3H into body water (14-45% of the dose). 17alpha-Ethynylestradiol, 2-hydroxy-17alpha-ethynylestradiol, 2-methoxy-17alpha-ethynylestradiol, 2-hydroxy-17alpha-ethynylestradiol 3-methyl ether and 16geta-hydroxy-17alpha-ethynylestradiol were measured in the "glucuronide" and pH1 fractions and mestranol, D-homoestrone-17a and D-homoestradiol-17abeta were also measured in the "glucuronide" fraction frum the urine to two of the women by reverse isotope dilution. Radioactive 2-methoxyestradiol accounted for less than 0.011% of the 14C dose in the "glucuronide" fraction of one of the women, consistent with the extent of de-ethynylation previously reported (Steroids, 25, 343 (1975).
An accurate sensitive method for the assay of D-norgestrel in human milk is described. The steroid is isolated from an ether extract of milk by Sephadex LH 20 chromatography in the system iso-octane-benzene-methanol (70:20:10 v/v). The radioimmunoassay utilises a specific antibody produced in rabbits against D-'norgestrel 3-(O-carboxymethyl) - oxime coupled to bovine serum albumin with D-norgestrel 3-(0-carboxymethyl) -oxime/ [125I]-iodohistamine conjugate as radioligand. Accuracy, sensitivity and blank value are satisfactory. Milk samples were obtained from three subjects treated with 30 microgram/day D-norgestrel, treatment commencing two weeks following parturition. Significant amounts of D-norgestrel were found, ranging between 92-135 pg/ml milk at the end of the first two-week treatment regimen. In two of three subjects, lower, but significant concentrations (53 pg and 35 pg/ml respectively) of steroid were found at the end of four weeks treatment. In the third subject, D-norgestrel could not be detected at this time. As a check on the specificity of the assay, three samples were submitted to additional chromatographic purification on alumina thin layer in the system benzene-cyclohexane-ethanol (70:27:3 v/v). Although this additional chromatographic step yielded somewhat lower values, agreement between the respective sets of results was good. The significance and implications of these findings are discussed.
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A randomized study, comparing serum medroxyprogesterone concentrations by the oral and intramuscular routes, was performed on 22 patients with persistent or recurrent endometrial adenocarcinoma by six institutions of the Gynecologic Oncology Group. The oral group (11 patients) received cutaneous Provera (medroxyprogesterone), 50 mg three times a day, and the intramuscular group (11 patients) received 300 mg of Depo-Provera (medroxyprogesterone) weekly for at least 2 months. Serum levels were evaluated at 0, 2, 4, 6, 8, 10, and 12 hours after administration and every day for the first week and weekly thereafter for 8 weeks. The mean serum levels (nanograms per milliliter) of medroxyprogesterone in the oral group were consistently higher than the corresponding mean levels of the intramuscular group. In addition, from the first through eighth weeks, the measurements (medians) for the oral group were statistically higher than those for the intramuscular group. Although the study indicates a significant increase in serum levels achieved by the oral route, the follow-up period of patients under study is too early to evaluate its clinical effectiveness as compared to the intramuscular route.
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Following the subcutaneous administration of estriol-6,7-3H to rats, biliary metabolites were identified and quantitated. Approximately 70% of the metabolites were excreted in the form of "glucosiduronate" conjugates. 3,17beta-Dihydroxy-2-methoxy-1,3,5(10)-estratrien-16-one was the major metabolite in this conjugate fraction. Significant amounts of 3,17beta-dihydroxy-1,3,5(10)-estratrien-16-one and 2,3,17beta-trihydroxy-1,3,5(10)-estratrien-16-one, as well as smaller quantities of 1,3,5(10)-estratriene-2,316alpha,17beta, tetrol and 2-methoxy-1,3,5(10)-estratriene-3, 16alpha, 17beta-triol, were also found. In 17alpha-ethinylestradiol-treated animals, the rate of excretion of radioactivity and the proportion of 16-oxo-17beta-ol metabolites found in the "glucosiduronate" fraction were reduced.
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Parachor is an additive constitutive property of a molecule and is related to the molar volume and the surface tension. The parachor of a steroid can be calculated from its constituent atoms and bonds. The parachor of a biologically active molecule is related to the ability of that molecule to permeate hydrophobic regions of cells, especially cellular membranes. An examination of the parachor values of a large number of steroids shows that these values are correlated with a number of different biological activities, from independent sources. The ability of steroids to release lysosomal enzymes from isolated lysosomes in vitro is inversely related to the parachor of the steroid. A similar relationship holds for the release of lysosomal beta-glucoronidase (EC 3.2.1.31) from isolated lysosomes of rat preputial gland following in vivo administration of steroids. The relative anti-inflammatory potencies of steroids by several assay methods are directly proportional to their parachors. The relative ability of corticosteroids to uncouple oxidative phosphorylation and to swell isolated mitochondria in vitro show a direct proportionality with the steroidal parachor. The percutaneous absorptions of steroids show good correlation with parachors, stratum corneum-water partition coefficients and amylcaproate-water partition coefficients; but not with hexadecane-water partition coefficients. The application of parachor as a structure-activity correlation parameter in drug design is likely to yield useful information. The advantages and limitations of the calculated parachor method are discussed.
Today, ENT is a popular synthetic progesteron for clinical use, and is well known to have some estrogenic activity. Estradiol-17beta (E2) or 17alpha-ethynyl estradiol (EE2) binding to the specific protein in the nuclear fraction of hypothalamus were examined by 3H-E2 exchange assay reported by Anderson. The possible mode of the estrogenic actions of ENT are as follows: 1) Conversion of ENT to EE2. 2) Estrogenic of ENT per se without changing the chemical structure. 3) Conversion of ENT to other estrogenic compounds except for EE2. In this experiment, 3H-ENT or 3H-testosterone (3H-T) was incubated with human placental microsomes and NADPH generating system for 1 hr at 37 degrees C, 3H-delta4AD, 3H-T and 3H-ENT were incubated also with homogenates of rat hypothalamus under the same conditions. Isolation and purification of the metabolites were performed by using phenolic separation and paper chromatography. Identification of EE2, a metabolite of ENT, was established by measuring the radiochemical homogenity with the authentic standard on paper chromatography. In another experiment where alkali was not used during the extraction procedure to avoid making artificial products, the conversion rate of ENT to EE2 was measured. This experimental data indicated that ENT was converted to 1beta-OH-ENT and to EE2 by human placental microsomes. The former compound was easily converted to EE2 in the presence of NaOH or by incubation with bile. In the incubation with hypothalamic preparation neither aromatization nor 1beta-hydroxylation of delta4AD, T and ENT were detected. In the exchange assays of E2 receptor, the animals were killed 1 hr after the administration of 25 mug of various steroids. The hypothalamic nuclear fraction was incubated with various 3H-steroids for 30 min at 37 degrees C. After washing this nuclear pellet, the radioactivity was counted. Administration of E2 in vivo resulted in the increase of the amount of 3H-EE2 bound to the nuclear fraction in vitro. But only a small increase of binding was observed in the similar experiment with 3H-ENT. 3H-EE2 was exchanged more abundantly after ENT administration than after EE2 injection. From the above results, it was concluded that the estrogenic effect of ENT is attributed to the EE2 converted in vivo. In addition, a possibility was proposed that ENT or its metabolites other than EE2 could regulate some step in the mechanism of estrogen action.
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Oestradiol-decanoate, dissolved in arachis oil and orally administered to rodents, produces oestrogenic effects. Compared on a molecular basis the ester has 0.1-1.0 times the activity of ethinyl oestradiol, dependent on the species and the parameter studied. The effects of oestradiol-decanoate are less or absent when the oil is omitted. It is likely that absorption of the steroid ester takes place via the intestinal lymphatics in conjunction with the oil.