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At least 145 records · Page 8Linked to original sources
PubMed1976

Biliary metabolites of estriol in the rat.

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.

Animals↗
PubMed1975

Anti-inflammatory steroids, lysosomal stabilization and parachor.

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.

Androgens↗
PubMed1975

[The experimental studies on the estrogenic activities of 17alpha-ethynyl-17beta-hydroxy-19-norandrost-4-en-3-one (ENT) (author's transl)].

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.

Androstenedione↗
PubMed1977

Oestrogenic activity of oestradiol-decanoate after oral administration to rodents.

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.

Administration, Oral↗
PubMed1979

Plasma medroxyprogesterone acetate levels following intramuscular or oral administration in patients with endometrial adenocarcinoma.

The concentration of medroxyprogesterone acetate (MPA) in plasma samples taken 24 h after intramuscular or oral administration of 100 mg daily doses of the drug to patients with endometrial adenocarcinoma was measured by radioimmunoassay. In general, a plasma level of about 4 ng/ml was found 24 h after the dose, independent of the route of drug administration. However, in three of the patients to whom intramuscular MPA was given, considerably higher values were found. A maximal plasma level was achieved three hours after ingestion of 100 mg MPA. This was followed by a rapid decline to 20-25% of the peak value after about 12 h. A rather small day-to-day intraindividual variation was found in daily blood samples taken just before administration of the next dose. However, considerable differences were found between individuals and it is concluded that this variation in plasma levels may be reflected in the clinical efficacy of the treatment. Thus further studies in which plasma values and clinical effectiveness are correlated seem to be indicated.

Adenocarcinoma↗
PubMed1975

Microbiological hydroxylation of norethisterone.

Hydroxylation of norethisterone by a large number of fungi has been investigated. 1alpha-Hydroxy-, 6beta-hydroxy-, 10beta-hydroxy-, 10beta,11beta-dihydroxy-15alpha-and 15beta-hydroxy-derivatives were formed from norethisterone. The microbiological dehydrogenation of 10beta-hydroxy-norethisterone resulting in 10beta,17beta-dihydroxy-17-ethynyl-1,4-estradien-3-one was also observed. The structure of transformation products was established by chemical and spectroscopical methods.

Chemical Phenomena↗
PubMedDate not supplied

Radioimmunoassay of norethindrone (17 alpha-ethynyl-17 beta-hydroxy-4-estren-3-one) and ethynyl-estradiol (17 alpha-ethynyl-1,3,5, (10)-estratien-3, 17 beta-diol). Application to human plasma determination of norethindrone after oral administration of this steroid.

The experiment conditions for the evaluation of Norethindrone (17 alpha-Ethynyl-17 beta-hydroxy-4-estren-3-one, NET) and Ethynyl-estradiol (17 alpha-ethynyl-1, 3, 5 (10) estratrien-3, 17 beta-diol, EE) by radioimmunoassay are described. A minimal quantity of 25 pg of these two steroids could be evaluated using different reduced metabolites of NET, very little cross reaction is observed with 200 pg of these metabolites. No effect was observed with estradiol for the EE-antiserum. The NET-antiserum was used to evaluate this steroid and ethynodiol diacetate after oral administration to female volunteers. Maximal values in the plasma (2-3% of the administered dose) was found between 1-3 h after administration and at 24 h a concentration of 0.1-0.3% still remained in the plasma.

Administration, Oral↗