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A Pousette

Publications and source records attributed to A Pousette.

At least 109 records · Page 6Linked to original sources
PubMed1985

Further characterization of the estrogen binding macromolecule in human pancreas.

The estrogen binding protein in human pancreas has been purified from pancreatic cytosol by chromatography on Concanavalin-A-Sepharose and hydroxyl-apatite followed by ion-exchange chromatography carried out using a fast-protein liquid chromatography apparatus (FPLC). The purified protein, still able to bind labelled [3H]estradiol, appeared as one single band corresponding to 31 K in SDS-gel electrophoresis. Total amino acid analysis revealed high levels of histidine, glutamic acid and leucine. The capacity of the purified protein to bind estrogens could be increased more than 4-fold by addition of a cytosolic factor, probably being a small peptide, that is present in crude cytosol, but lost during the purification procedure. The iodinated protein does not bind to DNA-cellulose or phosphocellulose, and shows no similarities to estrogen receptor proteins.

Amino Acids↗
PubMed1985

Influence of orchidectomy or oestrogen treatment on serum levels of pregnancy associated alpha 2-glycoprotein and sex hormone binding globulin in patients with prostatic cancer.

Peripheral serum levels of testosterone, immunoreactive oestrogens (E2), FSH, LH, prolactin and growth hormone (hGH) and two steroid-sensitive proteins, 'pregnancy-associated alpha 2-glycoprotein' (alpha 2-PAG) and sex hormone binding globulin (SHBG), were measured in patients with prostatic cancer before treatment and after orchidectomy or during combined oral and intramuscular oestrogen treatment. Following orchidectomy, the serum levels of testosterone and E2 decreased whilst the levels of FSH and LH increased significantly. No changes were noted in the serum levels of alpha 2-PAG, SHBG or prolactin. Oestrogen treatment significantly decreased the serum levels of testosterone, FSH and LH whilst levels of alpha 2-PAG, SHBG and prolactin were increased significantly. Serum levels of hGH during oestrogen treatment were significantly higher than in patients subjected to orchidectomy. These data are at variance with the established dogma of the oestrogen/androgen balance as a physiological regulator or liver protein synthesis, and indicate that factors other than the endogenous steroids may be operative. hGH may play an important role in this respect.

Aged↗
PubMed1984

Inhibition of steroid sulfatase activity by danazol.

The hydrolysis of dehydroepiandrosterone sulfate (DHAS) by human liver cells in culture and the hydrolysis of and formation of estradiol-17 beta (E2) from estrone sulfate (E1S) by human breast tumor preparations in vitro were studies in the presence and absence of danazol. In the latter tissue the effects of medroxyprogesterone acetate (MPA), trilostane, aminoglutethimide (AG) and tamoxifen were tested for comparison. Danazol at concentrations of 10(-6) - 1.4 X 10(-4) M strongly inhibited the hydrolysis of DHAS as well as the hydrolysis of and formation of E2 from E1S. With the exception of a slight inhibitory effect of trilostane upon E1S hydrolysis, the other four drugs did not inhibit the metabolism of E1S. Danazol, at concentrations corresponding to those occurring in vivo during therapy, is a potent inhibitor of steroid sulfatase activity. This may be one of the ways in which the drug affects peripheral and target tissue levels of steroid hormones.

Aminoglutethimide↗
PubMed1983

Adenocarcinoma of the pancreas--a hormone sensitive tumor? A preliminary report on Nolvadex treatment.

There are indications of possible effects of sex hormones on the pancreas. These include reports on steroid receptor proteins in pancreatic tissue, the purification and characterization of a highly specific, high capacity oestrogen binding protein in the human pancreas and capacity of human pancreatic tissue to convert the main peripheral oestrogen, oestrone sulphate, into the terminal biologically active oestradiol-17 beta. Furthermore, experiments in mice have shown accumulation of an anti-oestrogen, tamoxifen, in the pancreas. With this background, we have tried tamoxifen in 14 patients with unresectable adenocarcinoma of the pancreas. The median survival time was 8.5 months and three patients had a remarkably long survival time of 22 months. In a historical control group the median survival time was 2.5 months and no patients survived for more than 21 months. We have therefore started a randomized trial with tamoxifen in patients with unresectable pancreatic cancer. Even if anti-oestrogens are not the optimal form of therapy, other sorts of hormonal manipulation ought to be tried in pancreatic cancer.

Adenocarcinoma↗
PubMed1982

Fractionation of the rat ventral prostate with respect to isolation and exocytosis of the prostatic secretion protein.

The ventral prostate was fractionated into one mitochondrial and three microsomal fractions. The different fractions were characterized morphologically and chemically. An interesting finding was that upon homogenization the endoplasmic reticulum membranes often turned 'inside-out' giving rise to microsomes with ribosomes attached to the inside of the vesicles. The secretion of the prostatic secretion protein was studied by means of isotopic pulse labeling using radioactive leucine. Peak radioactivity in the microsomal fraction was obtained at 2 h after injection with a relatively rapid fall. The radioactivity in the secretory fluid displayed a continuous increase up to 8 h followed by a plateau. When prostatic secretion protein was purified from secretory fluid and microsomes using a Con A-Sepharose column it showed a typical precursor-product relationship with an early peak at 60 min in microsomal prostatic secretion protein followed by a peak in secretory fluid at 4 h. Vinblastine blocked the release of labeled secretion protein into the secretory fluid, a phenomenon characteristic for secretory proteins which are exocytosed by means of fusion between secretory granules and the plasma membrane. Following intravenous injection of [3H]estramustine, accumulation was seen in the secretory fluid. Some estramustine probably binds to newly synthesized prostatic secretion protein and follows the same route of intracellular transport and extracellular discharge as does prostatic secretion protein.

Animals↗
PubMed1982

Influence of pituitary and adrenocortical hormones on prostatic secretion protein, a major protein in rat prostate.

Prostatic secretion protein (PSP) is an androgen-sensitive, quantitatively important protein in rat ventral prostate which has been shown to inhibit the nuclear uptake and decrease the DNA-binding capacity of the androgen-receptor complex. In the present study, the influence of the pituitary, adrenals, and gonads on the concentration of PSP in the prostate was studied. Hypophysectomy decreased the concentration of PSP to about 10% of the control level, an effect similar to that obtained by castration. No effects on prostatic wet weight or PSP concentration were observed following substitution of hypophysectomized rats with human growth hormone, rat prolactin, or rat growth hormone. On the other hand, PSP concentration as well as wet weight of the prostate were normalized in hypophysectomized rats after administration of testosterone propionate. These results are in line with a direct extrahypophyseal effect of androgens on the prostate. Adrenalectomy did not affect the concentration of PSP, nor the wet weight of the prostate. Administration of estramustine decreased the wet weight of the prostate but did not affect the prostatic concentration of PSP in normal rats. Combined treatment with testosterone propionate and estramustine seemed to increase both the wet weight and the concentration of PSP more than administration of testosterone propionate alone. These results indicate a synergistic effect between estramustine and testosterone propionate.

Adrenal Cortex Hormones↗
PubMed1982

The distribution and metabolism of 14C-labelled tamoxifen in spayed female mice.

The distribution and metabolism of 14C-tamoxifen (a non-steroidal triaryl ethylene anti-oestrogen) have been investigated in ovarieectomized mice. The autoradiograms showed accumulation of radioactivity in the liver and the bile as an indication of an excretory pathway, but a rapid and high accumulation was also seen in the lung and the adrenals, organs normally not considered as target organs for tamoxifen. The liver and sebaceous glands could be detected on the autoradiograms up to fourteen days after a single intravenous dose. However, in most organs the amount of retained radioactivity was very low after 24 hours. By using the autoradiograms as a guideline a metabolic study was performed. High concentrations of unmetabolized tamoxifen was detected in the lung and the adrenals as well as in the pancreas. Relatively high amounts of a compound tentatively identified as 4-hydroxy-tamoxifen were present in the pancreas and the liver and there were also indications for the presence of N-desmethyl-tamoxifen in these tissues. These metabolites are considered to possess anti-oestrogenic activity.

Animals↗
PubMed1982

Purification and partial characterization of a 17 beta-estradiol-binding macromolecule in the human pancreas.

Studies have been performed in order to investigate the presence of estrogen-binding proteins in the human pancreas that may provide the biochemical basis for tissue-specific treatment of pancreatic carcinoma with estrogen-based cytotoxic drugs. Using in vitro techniques, an estrogen-binding macromolecule has been purified from pancreatic cytosol. With estradiol a ligand, Kd was calculated to be 1.7 X 10(-7) M, and this protein was found to constitute about 4% of the total protein content in the cytosol. No metabolism of estradiol was detected under the in vitro conditions used. Competition experiments indicated that, besides estradiol, the protein also had some affinity for estrone and estriol but not for testosterone, progesterone, or dexamethasone. The protein was purified to homogeneity using chromatography on concanavalin A and hydroxylapatite followed by preparative polyacrylamide gel electrophoresis. The purified protein, still able to bind, [3H]-estradiol, gave one single protein-staining band when analyzed using different electrophoretic systems. The steroid-protein and did not bind to phosphocellulose or DNA-cellulose and did not show any similarities to steroid receptor proteins. The complex has a Strokes' radius of 52 A and a sedimentation coefficient of 3S. The biological significance of the macromolecule is known, but the protein is probably synthesized in the pancreas since no similar protein could be detected in serum. Studies are now being carried out to investigate whether this novel protein in the human pancreas may interact with complexes between cytotoxic agents and estrogens and provide the basis for tissue-specific treatment of pancreatic carcinoma.

Cell Membrane↗
PubMed1982

Partial characterization and "quantitation" of a human prostatic estramustine-binding protein.

The [3H]estramustine-binding macromolecule in human prostate was partially characterized using a number of chromatographic procedures. Although human estramustine-binding protein (HEMBP) had a marked tendency to aggregate in several systems, a molecular weight of about 54,000 was determined by gel filtration on Sephacryl S-200 Superfine and high-performance liquid chromatography. A sedimentation-coefficient of about 3.6S was obtained for HEMBP when analyzed by sucrose density gradient centrifugation. Isoelectric focusing in polyacrylamide gels indicated an isoelectric point of 4.7 to 4.8, which was in agreement with the elution position of HEMBP following chromatofocusing on Polybuffer Exchanger 94. Furthermore, HEMBP was eluted from diethylaminoethyl-Sepharose with 0.23 M KCl, was retained by concanavalin A-Sepharose (indicating that HEMBP is a glycoprotein), but did not interact with Affi-Gel Blue. Special efforts were concentrated on establishing that HEMBP was a species distinct from human serum albumin. Separation between the [3H]estramustine-labeled HEMBP and the [3H]estramustine-human serum albumin complex was obtained both on sucrose density gradients by chromatography on Affi-Gel Blue, by chromatofocusing, by gel filtration, by isoelectric focusing, and on concanavalin A-Sepharose by affinity chromatography. Twenty-two of 27 human benign hyperplastic prostate cytosol samples were found to contain protein immunochemically similar to estramustine-binding protein (EMBP) purified from rat ventral prostate as determined by the EMBP radioimmunoassay method. Concentrations from 0.2 to 139.6 ng EMBP per mg of total cytosolic protein (mean, 19.3) were determined. Furthermore, four of seven prostatic cancer specimens as well as two of two normal prostatic specimens were also found to contain rat EMBP-immunoreactive material. The unequivocal demonstration of the presence of a HEMBP is of great potential interest in consideration of estramustine phosphate (Estracyt) therapy against prostatic carcinoma. It is not inconceivable that the concentration of HEMBP in the carcinomatous tissue will be of significance in determining the drug uptake in the malignant tissue.

Animals↗
PubMed1981

Analysis of chicken progesterone receptor structure using a spontaneous sheep antibody.

A spontaneous sheep antibody to chick progesterone receptor was characterized and used as a tool to study the receptor structure. The antibody, which is present to some extent in sera from about one-third of the sheep tested, binds to Staphylococcus aureus protein A--Sepharose and therefore appears to be an Igg. It is specific for the chick progesterone receptor and does not react with free progesterone or with any of the other proteins tested, including other receptors and corticosteroid binding globulin. The antibody os nonprecipitating and has a vary low titer (equivalence point = 2.5 pmol of receptor/mL of serum). The interaction of the receptor with the antibody was measured, and an apparent dissociation constant of 2 x 10(-9) M was determined from these studies. The antibody reacts equally well with the two receptor subunits A and B but does not appear to react with the native aggregate form found in the cytosol. Thus, the immunologic site is occluded in the aggregate, and therefore the antibody will be a useful probe for this important region of the proteins. The antibody recognition sites on the receptors were further characterized by analysis of a proteolytic digest of receptors by using an endogenous Ca2+-activated neutral protease. Competition studies using native receptor and receptor digests demonstrated that the antigenic site was not destroyed in the digest and was separated from the hormone binding fragment. We conclude that receptor subunits A and B have a cross-reactive immunologic site on a portion of the molecule other than the hormone binding domain.

Animals↗
PubMed1981

Influence of prostatic secretion protein on uptake of androgen-receptor complex in prostatic cell nuclei.

Prostatic secretion protein (PSP) is a major component of rat prostatic cytosol, and this protein is also found in the prostatic fluid. Purified PSP was found to inhibit the nuclear uptake of the [3H]methyltrienolone-receptor complex in vitro. Furthermore, purified PSP inhibited the binding of this androgen-receptor complex to DNA-cellulose. It is suggested that these effects of PSP may represent an intracellular control system regulating the concentration of PSP. Administration of estramustine, the dephosphorylated metabolite of the anti-cancer drug estramustine phosphate (Estracyt), to rats was found to decrease the weight of the prostate gland but to maintain the concentration of PSP, calculated as mg PSP/mg protein, at a constant level. In contrast, castration or administration of estradiol-17 beta valerate decreased the weight of the prostate gland as well as the concentration of PSP. These findings indicate that the mechanism of action of estramustine is at least partially different from that of estradiol-17 beta. Furthermore, it is suggested that estramustine may exert part of its action through its effects on the concentration of PSP.

Animals↗
PubMed1981

On the presence of prostatic secretion protein in rat seminal fluid.

The copulating plug collected from the tip of the penis from rats immediately after decapitation contains a protein very similar and probably identical to PSP (prostatic secretion protein); this protein has earlier been purified from rat prostatic cytosol and characterized. The protein present in the copulating plug interacts with [3H]estramustine and binds to the antibody raised against rat PSP. The concentration of the protein in the copulating plug is 400 ng/mg of total protein, when measured using the radioimmunoassay technique developed earlier for measurement of PSP in rat prostate. The [3H]estramustine-protein complex formed in a preparation of the copulating plug has an apparent molecular weight of about 50,000 and a sedimentation coefficient of about 3S when analyzed using sucrose density gradient centrifugation. The complex was retained on Concanavalin-A Sepharose indicating that the protein is a glycoprotein. Binding of the complex was also observed on hydroxylapatite and DEAE-Sephadex columns, from which it was eluted at 0.18 M KCl. Light microscope autoradiograms of rat sperms incubated with 125I-labeled PSP indicated that PSP is bound to all parts of the sperms. A macromolecule interacting with the PSP-antibodies is also present in human seminal fluid but at a concentration considerably lower than in rat seminal fluid. The present study shows that a macromolecule probably identical to prostatic secretion protein is present in the copulating plug from the rat. The biological role of this protein in normal male fertility is discussed.

Animals↗
PubMed1981

The presence in rat and human prostate of proteins that bind steroid-cytostatic complexes.

During studies on the uptake and distribution of estramustine phosphate (Estracyt) in the rat, a major protein in the rat ventral prostate was found that binds estramustine, estromustine, and several other steroid nitrogen mustard complexes. This protein, called estramustine-binding protein, shares many physicochemical characteristics with alpha-protein, prostatic-binding protein, and prostatein, each reported to constitute a major steroid-binding protein in the rat ventral prostate. There is every indication that these four names designate one and the same protein, the binding properties of which favor the binding of lipophilic compounds, and which has shown an affinity for estramustine and closely structure-related compounds that is 100- to 1000-fold higher than for the natural steroids. Also, the human prostate has been shown to take up and bind estramustine and estromustine. However, the binding entity (or entities) is still under intense investigation.

Animals↗
PubMed1981

Influence of sex hormones on prostatic secretion protein, a major protein in rat prostate.

Prostatic secretion protein (PSP) or estramustine-binding protein is a major protein in rat ventral prostate. The amount of PSP was measured per mg of cytosolic protein at different ages and after castration or administration of sex hormones. The amount of PSP is relatively low before puberty (25 microgram/mg of protein) but increases at about 28 days of age to about 670 microgram/mg of protein and then decreases to a constant level of about 300 to 400 microgram/mg of protein, which is stable until at least 9 months of age. Following castration, the amount of PSP decreased relatively slowly, but 6 days after castration less than 20% of the original amount of PSP was detected. Treatment with testosterone propionate (1 mg/day) for 2 weeks (starting 2 weeks after castration) restored precastration levels of PSP. It is concluded that PSP is an androgen-sensitive protein, and it is suggested that PSP should be considered as a probe for estimation of androgenic action on the prostate. PSP is similar to the so-called prostatic binding protein as well as to prostatein, and it is quite possible that the three proteins represent one and the same entity.

Aging↗