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Journal of Steroid Biochemistry

N H Simberg, J T Murai, P K Siiteri
The in vitro binding affinities of toremifene (TOR), 4-hydroxy toremifene (4-OH-TOR) and several other metabolites for the rat uterine cytosolic estrogen receptor were compared with those of tamoxifen (TAM) and 4-hydroxy tamoxifen (4-OH-TAM). Only small differences were observed and the binding affinities of both 4-hydroxy metabolites were similar to that of estradiol (E2). Uterine uptake and subcellular distribution of [3H]TOR and [3H]TAM were then compared at 1, 8 and 72 h after administration to castrated rats...
June 22, 1990: Journal of Steroid Biochemistry
L Kangas
New compounds were synthesized with the aim to develop new anti-estrogenic antitumor drugs. The biological properties of the molecules were screened by (1) estrogen receptor (ER) binding, (2) effect on MCF-7 cells, (3) uterotrophic effect and inhibition of estradiol induced uterotropic effect and (4) antitumor effect in DMBA induced rat mammary cancer. One of the molecules, Fc-1157a = toremifene, exhibited the following characteristics: competitive inhibition of [3H]estradiol binding to ER (IC50 = 0.3 mumol/l), inhibition of MCF-7 cell growth in a concentration-dependent manner and cell-killing effect at higher than 3 mumol/l concentrations...
June 22, 1990: Journal of Steroid Biochemistry
E R Barnea, S Avigdor
The estrogen phenol A-ring metabolism was investigated in the first trimester placenta using radioenzymatic techniques. In untested explants cultured for 16 h, estrogen hydroxylase (EH) but not catechol-O-methyl transferase (COMT) activity was increased significantly 1.8-fold (P less than 0.05). Cultures made in the presence of chemoprotectors, 25 microM of 1-phenylazo-2-naphthol (Sudan I) and coumarin but not 2(3)-tert-butyl-4-hydroxyanisole (BHA) caused a significant increase in EH activity, 1.8- and 2.2-fold, respectively (P less than 0...
February 1990: Journal of Steroid Biochemistry
C Chakraborty, Y M Huet-Hudson, S K Dey
Microsomal oestradiol-2/4-hydroxylase (OE-2/4-H) and cytosolic catechol-O-methyltransferase (COMT) (EC activity in the uteri of pregnant and pseudopregnant rabbits during the periimplantation period were studied. The apparent Km for the 4-hydroxylation of oestradiol (3.18 microM) was considerably less than for the 2-hydroxylation reaction (13.36 microM), whereas the Vmax were almost equal. This suggests that 4-hydroxyoestradiol (4-OH-OE2) is the predominant product of OE-2/4-H in the rabbit uterus...
January 1990: Journal of Steroid Biochemistry
M Chambon, H Rochefort, H J Vial, D Chalbos
Using electron microscopy, in the human breast cancer cell line T47D, the synthetic progestin R5020, and 5 alpha-dihydrotestosterone were shown to increase significantly the number of lipid droplets per cell section compared to control cells or estradiol- and dexamethasone-treated cells. Lipid accumulation, as measured by Oil Red O dying and by [2-14C]acetate incorporation, was observed at concentrations as low as 10 pM R5020 and 1 nM 5 alpha-dihydrotestosterone, and was always more abundant after progestin treatment...
November 1989: Journal of Steroid Biochemistry
C M Klinge, D T Knox, R A Bambara, S Zain, R Hilf
Interaction of [3H]4-hydroxytamoxifen-charged estrogen receptor [( 3H]AER) with nuclei was compared to that of [3H]17 beta-estradiol-charged estrogen receptor [( 3H]ER) in vitro. Specificity of [3H]AER binding was demonstrated since more than 90% of [3H]AER binding was displaced by ten-fold excess estradiol-charged ER. For R3230AC tumors, the number of [3H]AER binding sites was approximately 40% lower than the number of [3H]ER binding sites. There were no differences in affinity of binding of these receptors complexes (Kd range 0...
September 1989: Journal of Steroid Biochemistry
G S Prins
In order to understand the hormonal regulation of androgen receptors (AR) in the separate lobes of the rat prostate gland, the present study examined AR levels in the ventral, dorsal and lateral prostate lobes as a function of androgen withdrawal to complete prostatic regression and subsequent testosterone replacement. In the intact rat, the 3 prostate lobes contained significantly different amounts of androgen binding sites. Mean number of total cellular AR in the ventral, dorsal and lateral lobes was 7370, 1690, and 1015 fm/mg DNA, respectively...
September 1989: Journal of Steroid Biochemistry
J L Thomas, R P Myers, R C Strickler
In human placenta, 3 beta-hydroxy-5-ene-steroid dehydrogenase and steroid 5----4-ene-isomerase, an enzyme complex found in microsomes and mitochondria, synthesizes progesterone from pregnenolone and androstenedione from fetal dehydroepiandrosterone sulfate. The dehydrogenase and isomerase activities of the mitochondrial enzyme were copurified (733-fold) using sequential cholate solubilization, ion exchange chromatography (DEAE-Toyopearl 650S), and hydroxylapatite chromatography (Bio-Gel HT). Enzyme homogeneity was demonstrated by a single protein band in SDS-polyacrylamide gel electrophoresis (monomeric Mr = 41,000), gel filtration at constant specific enzyme activity (Mr = 77,000), and a single NH2-terminal sequence...
August 1989: Journal of Steroid Biochemistry
C H Van Aswegen, R H Purdy, J L Wittliff
The binding of catechol estrogens, epoxyenones and methoxyestrogens was evaluated using estrogen receptors in cytosol prepared from human breast cancers. The relative affinity of 2-hydroxyestradiol, a metabolite formed in vitro from estradiol-17 beta by breast cancer cells, was indistinguishable from that of estradiol-17 beta. 4-Hydroxyestradiol, which is also a metabolite of estradiol-17 beta, associated with the estrogen receptor with a relative affinity approximately 1.5-fold greater than that of estradiol-17 beta...
April 1989: Journal of Steroid Biochemistry
B Bouillard, V Albaladejo, M O Joly-Pharaboz, Y Morel, J Andre
UNLABELLED: Estrogen receptors (ER) of the MtTF4 tumor whose growth is inhibited by estradiol (E2) were analyzed and compared to those of tissues whose growth is stimulated by E2 (uterus and pituitary gland). Cytosol prepared in buffer containing protease inhibitors was incubated with [3H]tamoxifen aziridine ([3H]TAZ) in the presence or absence of non-radioactive competitor. The labeled proteins were precipitated, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in denaturing conditions and detected by fluorography...
January 1989: Journal of Steroid Biochemistry
D A Sullivan, L E Hann
The objective of the current investigation was to explore the processes underlying the androgen control of tear IgA and to determine whether hormone exposure also modifies tear IgG content. In addition, studies evaluated the impact of diabetes on the androgen regulation of secretory immunity in the eye. Tears and lacrimal glands were collected from age-matched, adult male rats, which had undergone hypophysectomy, selective ablation of the anterior pituitary, streptozotocin-induced diabetes, sham-surgery and/or orchiectomy and had been exposed to vehicle or physiological amounts of testosterone for varying periods of time...
1989: Journal of Steroid Biochemistry
A E Wakeling
Pure and partial agonist antioestrogens, exemplified by ICI 164,384 and tamoxifen or 4-hydroxytamoxifen (4'-OHT) respectively, differ in their capacity to inhibit the growth of MCF-7 human breast cancer cells. Under basal conditions which maintain but do not permit proliferation of MCF-7 cells, growth rate was enhanced by oestradiol, Phenol Red, insulin and 4'-OHT but not by ICI 164,384. Oestradiol and insulin together enhanced cell growth rate synergistically. 4'-OHT, but not ICI 164,384, similarly increased insulin-stimulated cell growth in the absence of oestradiol...
1989: Journal of Steroid Biochemistry
E M Dax, N S Pilotte, W H Adler, J E Nagel, W R Lange
We investigated effects of 9-ene-tetrahydrocannabinol (THC) on endocrine and immunological function. Seventeen male volunteers entered into a double blind, randomized study to receive oral THC (10 mg t.i.d. for 3 days and on the morning of the fourth day) or placebo, after at least 2 weeks of abstinence. Plasma prolactin, ACTH, cortisol, luteinizing hormone and testosterone were not altered during or after THC, compared with baseline concentrations. Tests of lymphocyte function showed no differences compared to baseline between THC and placebo groups...
1989: Journal of Steroid Biochemistry
W de Boer, J Bolt
The nuclear estrogen receptor from calf uterus was used to investigate the possible relationship between receptor transformation (4S to 5S) and receptor activation (DNA binding). Receptors extracted from nuclei after exposure of uterine tissue tc [3H]estradiol sedimented at 5.2S, the characteristic value of the transformed receptor. After storage at -20 degrees C the receptor sedimented at 4.0S, indicating conversion of the 5S form into the non-transformed 4S form. Upon reincubation at 28 degrees C the 4S form transformed into the 5S form following second-order kinetics...
December 1988: Journal of Steroid Biochemistry
J L Thomas, E A Berko, A Faustino, R P Myers, R C Strickler
In human pregnancy, placental 3 beta-hydroxy-5-ene-steroid dehydrogenase and steroid 5----4-ene-isomerase produce progesterone from pregnenolone and metabolize fetal dehydroepiandrosterone sulfate to androstenedione, an estrogen precursor. The enzyme complex was solubilized from human placental microsomes using the anionic detergent, sodium cholate. Purification (500-fold, 3.9% yield) was achieved by ion exchange chromatography (Fractogel-TSK DEAE 650-S) followed by hydroxylapatite chromatography (Bio-Gel HT)...
November 1988: Journal of Steroid Biochemistry
B Cypriani, C Tabacik, B Descomps, A Crastes de Paulet
The effects of estradiol (E2), 4-hydroxy-tamoxifen (OH-Tam), and LY117018 on cholesterogenesis were investigated in two human breast cancer cell lines (MCF-7 and BT20), and in rat hepatoma (HTC) and fibroblastic (NRK-49F) cell lines. It was found that 10(-10) M E2 stimulated and 10(-8) M OH-Tam inhibited cholesterol synthesis in the estrogen-sensitive MCF-7 cell line. The OH-Tam effect occurred in less than 15 min whereas E2 only stimulated after 8 h. The inhibition of cholesterol synthesis was not reversed by E2...
November 1988: Journal of Steroid Biochemistry
C Chouvet, E Vicard, L Frappart, N Falette, M F Lefebvre, S Saez
The antiestrogenic activities of Tamoxifen have been well documented and this molecule has been successfully used in the treatment of hormone dependent breast cancer. In the present experiments we demonstrate that 4-hydroxy-Tamoxifen (OH-TAM) is able to reduce the growth of the BT-20 cell line which is devoid of estrogen and progesterone receptors. Various parameters have been investigated in growth studies under control conditions and in the presence of OH-TAM. Cell numerations, [3H]thymidine incorporation per cell or per microgram of DNA have shown that OH-TAM reduces the growth rate in proportion to its concentration from 10(-9) M to 10(-6) M...
October 1988: Journal of Steroid Biochemistry
B W Ennis, W E Stumpf
The in vivo binding of antiestrogen in nuclei within the uterine stromal, epithelial and myometrial tissue compartments was compared to that of estrogen 2-48 h after injection. Tissue binding and retention of radioactivity was also studied. Immature rats were injected s.c. with 0.36 microgram [3H]hydroxytamoxifen [( 3H]TAM(OH] or 0.24 microgram [3H]estradiol [( 3H]E2) in oil. At 2, 4, 8, 12, 24 and 48 h after injection, uteri were processed for thaw-mount autoradiography and, along with other tissues, for liquid scintillation counting...
October 1988: Journal of Steroid Biochemistry
G Parmar, M G Elder, J O White
The oestrogen receptor (ER) present in human breast cancer cytosol was resolved by high performance size exclusion chromatography into a high molecular weight form (300 kDa) either alone or together with a lower molecular weight species (60 kDa). In tumours that contained the 60 kDa species there was a significant increase both in ER activation, determined by binding to oligo(dT)-cellulose, and the concentration of progesterone receptor (PR). Despite cytosolic ER being a potential homogenisation artefact, qualitative differences observed in vitro may reflect aspects of tumour biology in vivo...
October 1988: Journal of Steroid Biochemistry
J L Borgna, J Scali
Diethylpyrocarbonate differentially inhibited the specific binding, in lamb uterine cytosol, of estradiol (inhibition approximately 90% with 4 mM reagent) and 4-hydroxytamoxifen (inhibition approximately less than 50% with 4-16 mM reagent), a potent triphenylethylene antiestrogen. Saturation analysis experiments indicated that the effects of diethylpyrocarbonate were due to progressive but differing decreases in the concentration of binding sites for the two ligands, with no apparent change in the affinity constants...
October 1988: Journal of Steroid Biochemistry
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