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Results for “Progesterone Congeners”

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At least 19 recordsLinked to original sources
PubMed1987

Progesterone derivatives that bind to the digitalis receptor: synthesis of 14 beta-hydroxyprogesterone. A novel steroid with positive inotropic activity.

The synthesis of 14-hydroxy-14 beta-pregn-4-ene-3,20-dione (14 beta-hydroxyprogesterone) is described. This novel steroid is about 10 times more potent than progesterone and one-tenth as potent as ouabagenin in an [3H]ouabain radioligand binding assay and is the first in a series of progesterone congeners that interact at the cardiac glycoside receptor both to possess the C/D cis ring junction and to enhance contractility of isolated cardiac tissue.

Animals↗
PubMed1990

Inhibitory effect of synthetic progestins, 4-MA and cyanoketone on human placental 3 beta-hydroxysteroid dehydrogenase/5----4-ene-isomerase activity.

Human placental 3 beta-hydroxysteroid dehydrogenase/5----4-ene isomerase (3 beta-HSD) purified from human placenta transforms C-21 (pregnenolone and 17 alpha-hydroxy pregnenolone) as well as C-19 (dehydroepiandrosterone and androst-5-ene-3 beta, 17 beta-diol) steroids into the corresponding 3-keto-4-ene-steroids and is thus involved in the biosynthesis of all classes of hormonal steroids. Trilostane, epostane and cyanoketone are potent inhibitors of 3 beta-HSD with Ki values of approximately 50 nM. 4-MA, a well known 5 alpha-reductase inhibitor, is also a potent inhibitor of 3 beta-HSD with a Ki value of 56 nM. Synthetic progestin compounds such as promegestone and RU2323 show relatively strong inhibitory effects with Ki values of 110 and 190 nM, respectively. Cyproterone acetate, a progestin used in the treatment of hirsutism, acne and prostate cancer as well as norgestrel and norethindrone that are widely used as oral contraceptives also inhibit 3 beta-HSD activity at Ki values of 1.5, 1.7 and 2.5 microM, respectively.

3-Hydroxysteroid Dehydrogenases↗
PubMed1978

The effect of progesterone analogues, naturally occurring steroids, and contraceptive progestins on hypothalamic and anterior pituitary delta4-steroid (progesterone) 5alpha-reductase.

The effects of a number of steroids on the conversion of progesterone to 5alpha-dihydroprogesterone by hypothalamic and pituitary progesterone 5alpha-reductase have been investigated. Using enzyme preparations from female rats and 3H-progesterone as substrate, 5alpha-reduced products (5alpha-dihydroprogesterone and 3alpha-hydroxy-5alpha-pregnan-20-one) were analyzed by reverse isotopic dilution analysis. The amount of total 5alpha-reduced products formed was compared in the presence and absence of the test steroid. Derivatives lacking the delta4 and/or the 3-keto moiety were without effect. Corticosterone had no effect. 16beta-Methylprogesterone inhibited progesterone 5alpha-reduction in both tissues by at least 65%, while the 2alpha-, 6alpha-, and 7alpha-methylated derivatives had lesser effects. 3-Oxo-4-pregnene-20beta-carboxaldehyde and 21-fluoroprogesterone were potent inhibitors. 17-Hydroxyprogesterone was a competitive inhibitor (substrate) with Ki's of 0.27 micrometer (pituitary) and 0.29 micrometer (hypothalamus). Medroxyprogesterone exerted little inhibitory effect. Of the 19-nor-steroids examined, only norethindrone appreciably inhibited the 5alpha-reduction. These results suggest that some natural delta4-3-ketosteroids can modify enzymatic activity. Also, inhibitory analogues may be useful for studies on the role of this 5alpha-reduction of progesterone.

3-Hydroxysteroid Dehydrogenases↗
PubMed1978

Synthetic progestins: in vitro potency on human endometrium and specific binding to cytosol receptor.

The relative potency of six commonly used synthetic progestins has been evaluated in an organ culture system for human endometrium. The affinities of these progestins for endometrial progesterone receptor were also evaluated after removing the CBG-like protein by spheroidal hydroxylapatite chromatography. All six progestins induced an increase in tissue glycogen during culture at lower concentrations than did progesterone; only one (medroxyprogesterone acetate) had a relative affinity greater than progesterone. The relative potencies and affinities of the synthetic progestins were found to have the same relative order but to differ in relative magnitude.

Chromatography↗
PubMed1977

Production of antisera against contraceptive steroids.

A four step synthesis of 6-(0-carboxymethyl) oximinoethynylestradiol is reported. This compound, 6-(0-carboxymethyl) oximinomestranol, the 3-(0-carboxymethyl) oximes of norethindrone and norgestrel and the 3-hemisuccinate of ethynylestradiol were synthesized and conjugated with bovine serum albumin. Rabbits were immunized at 3 dose levels of haptene (20, 66 and 200 nmoles) and eight weeks later with a booster containing 66 nmoles of haptene. The antibody titer and association constant of responding rabbits was nearly independent of dose although most antibody production occurred after the booster injection. Antibodies to mestranol crossreacted more than 100 percent with ethynylestradiol and to a small extent with norethindrone and norgestrel.

Animals↗
PubMed1990

Comparison of the physical properties of the nuclear progesterone receptor, bound to antiprogestin RU 486 or progestin ORG 2058, following limited proteolysis.

The susceptibility of the progesterone receptor, liganded either by the antiprogestin RU 486 or by the progestin ORG 2058, to chymotrypsin and trypsin degradation was investigated. The nuclear fraction was isolated from T47D cells previously exposed either to 0.1 microM [3H]RU 486 or to 0.1 microM [3H]ORG 2058. The proteolytic digestion was performed on the micrococcal nuclease hydrolysate. The molecular weights of the receptor fragments were calculated, in high salt buffer, from the sedimentation coefficients determined on a sucrose gradient and from the Stokes radii estimated by gel filtration on an Agarose A-0.5 m column. Micrococcal nuclease solubilized receptor forms with molecular weights of 80,000 and 75,000 for the antiprogestin- or progestin-liganded receptor, respectively. Chymotrypsin degraded these receptor forms to fragments with molecular weights of 23,000 either for the antiprogestin- or progestin-liganded receptor. Similar molecular weights of 23,000 were calculated for the progesterone receptor liganded either by the antiprogestin RU 436 or the progestin ORG 2058 following trypsin cleavage. We conclude that the degradation pattern of the progesterone receptor liganded either by the antiprogestin RU 486 or the progestin ORG 2058 following chymotrypsin or trypsin digestion seems to be similar.

Cell Line↗
PubMed1986

Properties of progestin-binding protein in benign hypertrophic human prostate.

RU 27987 is a new ligand for progesterone receptor and binds in high affinity to nuclei of target tissues of progesterone. Using this compound, progestin-binding components in the benign hypertrophic human prostate were studied, and compared with those examined with R 5020, a conventional ligand, in the study of progesterone receptor. In cytosols, the binding affinity of RU 27987 was higher than that of R 5020, and the number of maximum binding sites for RU 27987 seemed to be large but correlated well with those of R 5020. The binder for RU 27987 sedimented at 8.6 S, and the binding was specific to progestational steroids, indicating that binding properties of this binder in the cytosols are identical to those for R 5020. Although there was no binding with R 5020 in the nuclear extract, a small amount of specific binding with RU 27987 was detected. However, the cytosol bound with RU 27987 was not retained in DNA Sepharose and no specific binder for RU 27987 in the nuclear extract was observed in a sucrose density gradient centrifugation. From these observations, it was assumed that the nuclear binding observed was attributable to contamination of the cytosolic binder. The results obtained in the present study suggest that the progestin-binding component in the benign prostatic hypertrophy is not the progesterone receptor but a high affinity binder for progestins whose physiological role is not clear at present.

Alpha-Globulins↗
PubMed1988

[Progestogen therapy in the treatment of endometrial cancer--clinical results and mechanism of steroid action].

The use of medroxyprogesterone acetate (MPA) in therapy of patients with endometrial cancer has been recently examined by the Japan Gynecological Cancer Treatment Group. The response rate of oral MPA was 23.6% (13/55 evaluables) and the average period up to the onset of response was 15.2 weeks (4-28 wks). The response rate was higher in well-differentiated tumors than in poorly differentiated ones. Although it is well known that steroid hormone action is mediated by steroid hormone receptor, the presence of progesterone receptor in cancer tissue seems to be not absolutely necessary for the responsibility to MPA, a potent progestational compound. The reason was studied, in vitro, in our laboratory by using the technique of human tumor clonogenic assay. In this system, MPA showed a marked suppressive effect on the colony formation of endometrial cancer cells. Similar effects were also observed with progesterone, 17 alpha-hydroxyprogesterone caproate and megestrol acetate. Norethindrone and norgestrel, which are both potent progestational compounds, showed almost no anticancer activity on Ishikawa cell in this in vitro system. It became clear that progestational activity was not always associated with anticancer activity, and norethindrone had no influence on the inhibitory effect of MPA, although norethindrone has a strong affinity for progesterone receptor. Similarly, RU 486, which is known as a potent antiprogestogen agent and has a high affinity to progesterone receptor, did not influence the effect of MPA. These results clearly indicated that the anticancer activity of MPA was not mediated by high affinity low capacity progesterone receptor, and a pharmacological effect must be considered for understanding the effect of MPA on endometrial cancer.

Estrenes↗
PubMedDate not supplied

[Luteal insufficiency and elevation of sex-binding proteins by demegestone].

Demegestone, a norprogesterone derivative, was administered during the luteal phase in 6 normally ovulatory women and in 10 patients with luteal insufficiency. Demegestone decreased the LH surge and the plasma concentrations of estradiol and progesterone in the normally ovulatory women and did not modify the binding capacity of sex steroid binding protein (SBP). In the patients with luteal insufficiency, demegestone increased significantly SBP (0.94 +/- 0.24 vs 1.32 +/- 0.56 micrograms/dl, p less than 0.05) and decreased the free testosterone index (T/SBP) (38.8 +/- 33.3 vs 25.4 +/- 18.5, p less than 0.05). Transcortin, was unchanged during demegestone treatment in both groups of women. The results showed that demegestone did not exercise androgenic activity on SBP conversely to the nortestosterone derivatives which decrease SBP and confirmed that progesterone and norprogesterone derivatives influence positively the regulation of SBP.

Adult↗
PubMed1978

Progesterone receptor in the rat anterior pituitary: effect of estrogen priming and adrenalectomy.

The present study was done to determine if a progesterone receptor is present in rat pituitary. Cytosol was labeled with 3H-progesterone (3HP) or 3H-R5020 (3HR) and subjected to sucrose-glycerol density-gradient centrifugation. Serum progesterone was measured for correlation with progesterone receptor levels. Two 3HP-binding peaks (4S + 6S) were evident in uterine and pituitary cytosols. The 4S peak was eliminated by competition with unlabeled cortisol leaving a single 6S peak (progesterone receptor). Estradiol (E) priming of the male or female rat increased progesterone receptor levels in pituitary cytosol as demonstrated using 3HP and 3HR, and pituitary progesterone receptor bound 3HR with a higher affinity than 3HP. Following adrenalectomy of gonadectomized rats, progesterone receptor levels were increased in pituitary and uterine cytosol of both E-primed and unprimed groups. An inverse relationship was established between serum progesterone and progesterone receptor levels in the uterus and pituitary suggesting that stress-induced adrenal progesterone secretion significantly influences progesterone receptor levels in the rat. These results demonstrate an estrogen-inducible progesterone receptor in the rat pituitary with properties similar to those of the uterine progesterone receptor.

Adrenalectomy↗