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Biomedical subjects

B Högberg

Publications and source records attributed to B Högberg.

At least 19 recordsLinked to original sources
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

High-affinity binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin in cell nuclei from rat liver.

The intranuclear binding of radioactive 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in rat liver has been studied both in vivo and in vitro. Following the intravenous administration of [1,6-3H]TCDD, a maximum uptake by cell nuclei could be observed at 2 h after injection with a concurrent decrease in the cytosolic uptake. Using linear sucrose density gradient centrifugation, dextran-coated charcoal adsorption assay, DEAE-Sepharose ion-exchange chromatography, competition, enzymatic and saturation studies, a high-affinity binding protein for TCDD in liver cell nuclei could be demonstrated both in vivo and after an exchange in vitro of intravenously administered unlabelled 2,3,7,8- tetrachlorodibenzofuran (TCDBF) for [3H]TCDD. Sucrose density gradient analysis showed a size of 4-5 S for both the cytosolic and nuclear TCDD binding entity. The specific binding of [3H]TCDD to nuclear components was heat labile and saturable and had an equilibrium dissociation constant of 1.05 nM. Based on a differential susceptibility to specific hydrolases, i.e. DNAase, RNAase, trypsin and pronase, the binding entity appears to be a 4-5 S salt-extractable 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 TCDD receptor in rat intestinal mucosa and its possible dietary ligands.

Induction of aryl hydrocarbon hydroxylase (AHH) by polycyclic aromatic hydrocarbons and other inducers such as 2,3,8-tetrachlorodibenzo-p-dioxin (TCDD) is known to occur following binding of the inducer to a soluble receptor protein similar to steroid hormone receptors. This receptor is usually called the TCDD receptor, since TCDD has the highest affinity of all known ligands for the receptor. In the present paper a receptor for TCDD in cytosol from rat intestinal mucosa has been studied, using isoelectric focusing in polyacrylamide gel. This receptor's biochemical properties were found to be similar to those of the TCDD-receptor in rat liver cytosol. The dissociation constant (Kd) of the 3H-TCDD-receptor complex in rat intestinal mucosa was 0.7-3.1 nM, and it was present at a concentration of 70-80 fmol/mg protein. Starvation did not significantly increase the receptor level. The affinities of some potential dietary ligands for the TCDD receptor in rat intestinal mucosa were also studied. Indole-3-carbinol had 1/2,600 of the affinity of TCDD for the receptor protein. Butylated hydroxyanisole (BHA), transstilbene oxide and quercetinpentamethylether competed even more weakly with 3H-TCDD for binding to the receptor. The biological significance of the occurrence of low-affinity ligands of dietary origin for the TCDD receptor is uncertain at the present time.

Animals↗
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

Interaction of the hepatic receptor protein for 2,3,7,8-tetrachlorodibenzo-rho-dioxin with DNA.

2,3,7,8-Tetrachlorodibenzo-rho-dioxin (TCDD) binds to a specific, high-affinity, low-capacity protein in rat liver cytosol. The TCDD-receptor complex is a large molecule with a Stokes radius of 6.6 nm as determined by gel filtration on calibrated columns. The receptor complex sediments at 5.0 S on glycerol gradients. The calculated molecular weight from the physical parameters was 136 000 and the frictional ratio 1.79. The TCDD-receptor complex binds to DNA-cellulose without preceding heat activation or incubation at high ionic strength. The receptor must first bind TCDD before it can interact with DNA. The DNA-binding ability can be removed from the TCDD receptor by limited proteolysis with trypsin. This treatment does not affect the TCDD-binding site of the receptor. The proteolytic fragment of the TCDD-receptor complex containing the TCDD-binding site but not the ability to bind to DNA appears to be approximately the same size as the native receptor, as judged from chromatography of Sepharose CL-6B and glycerol gradient centrifugation.

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

Intracellular localization of estramustine in rat ventral prostate in vitro.

With the aim of studying the mechanism behind the effect of estramustine in the treatment of prostatic carcinoma, the intracellular fate of the drug has been investigated in rat ventral prostate in vitro. Minced tissue was incubated with [3H] estramustine under different conditions, homogenized, and submitted to isopycnic centrifugation on a sucrose gradient using the recently introduced vertical tube rotor. The subcellular localization of the drug was determined by comparison between the distribution of radioactivity in the gradient fractions and the activities of a number of marker enzymes. No metabolism of estramustine occurred as judged by thin-layer chromatography. After incubation of the minced prostate tissue for 1 hour at 30 degrees C with 0.15 microM of [3H] estramustine, most of the drug was recovered in the cytosol fractions which also contained the highest concentrations of the estramustine-binding protein. However, after incubation with 220 microM of estramustine, most drug equilibrated in heavier fractions with high concentrations of N-acetyl-beta-glucosaminidase and cathepsin B, marker enzymes for the lysosomes as well as NADPH:cytochrome c reductase, marker enzyme for the endoplasmic reticulum. Extending the incubation time and increasing the temperature reduced the amount of estramustine equilibrating in the heavy fractions and concomitantly increased the portion localized in the cytosol. During all incubation conditions, very little drug seemed to accumulate in the nuclei since the drug distribution was completely different from that of DNA. This suggests that effects other than interaction with nuclear DNA might be of importance for the cytotoxic effect of estramustine.

Acetylglucosaminidase↗
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

Hormonal effects of different doses of estramustine phosphate (Estracyt) in patients with prostatic carcinoma.

Ten patients with previously untreated prostatic carcinoma were studied to evaluate the hormonal effects of different doses of estramustine phosphate (Estracyt). The drug was given by mouth in increasing doses; during the first month 70 mg daily, during the second 140 mg, during the third 280 mg and during the fourth and following months 560 mg. The following hormonal parameters were studied before the treatment and then once weekly during a period of four months: testosterone, dihydrotestosterone, androstenedione, cortisol, FSH and LH. The levels of the steroids were also re-assessed one to two years later. The patients were also followed clinically at regular intervals. Initial testosterone levels of approximately 20 nmol/l plasma were reduced to approximately 0.6 nmol/l already by the lowest Estracyt dose of 70 mg/day. No further decrease was obtained by a stepwise increase of doses up to 560 mg/day. The plasma levels of dihydrotestosterone, androstenedione, FSH and LH were also reduced significantly following the administration of the lowest daily Estracyt dose and then remained at that low level. Cortisol levels increased steadily during the four months of the study. After longterm treatment the hormonal indices were by and large the same as during the last initial treatment period. Initially, the clinical effect of the treatment was excellent. In 4 patients, however, the therapy had to be discontinued after some time, because of complicating oedema (2 patients) or refractoriness to therapy (2 patients). Three years after initiating the therapy 6 patients still were on Estracyt treatment. All of them were doing well subjectively. In 5 patients the prostatic cancer was in remission or at least stable. In one patient, however, skeletal metastases were progressing. In conclusion, Estracyt was found to possess a maximal hormonal (oestrogenic) effect already in doses far below those usually recommended.

Administration, Oral↗
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↗