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Biomedical subjects

K Pollow

Publications and source records attributed to K Pollow.

At least 91 records · Page 5Linked to original sources
PubMed1983

Synthesis of biotin-labelled dexamethasone derivatives. Novel hormone-affinity probes.

A new, general methodology for 'sandwich' affinity chromatography of steroid hormone receptors is proposed, the part purification of the human spleen tumor glucocorticoid receptor is quoted as an illustration. 9-Fluoro-16 alpha-methyl-11 beta, 17-dihydroxy-1,4-androstadiene-3-one-17 beta-carboxylic acid was coupled to biotin using pentamethylenediamine (BioDex 1) as a spacer. The bifunctional derivative binds to glucocorticoid receptors and avidin-Sepharose and efficiently protects the glucocorticoid receptor against inactivation when previously added during homogenisation. We have standardized the capacity and optimum conditions for elution of receptor-BioDex-1 complexes which are bound to avidin-Sepharose. Receptor purification of several thousand fold can be obtained with good yield.

Affinity Labels↗
PubMed1983

16 alpha-iodo-3,17 beta-estradiol: a stable ligand for estrogen receptor determinations in tissues with high 17 beta-hydroxysteroid dehydrogenase activity.

Recently, the successful synthesis of radioiodinated 16 alpha-iodo-3,17 beta-estradiol-[125I] [125I]E2 was reported [1]. This new ligand has similar binding characteristics to the estrogen receptor (ER) [2-5] as the currently used tritium labeled estradiol [3H]E2. However, it offers several advantageous features: (a) high specific activity (theoretically 2,000 Ci/mmol) [1]; (b) minor problems with radioactive waste due to its short half life and (c) the possibility of simultaneous determination of ER and progesterone receptors (PgR) by double labeling with [125I]E2 and [3H]R5020 [6, 7]. As we are presently trying to determine ER and PgR in human placental cytosols we were interested in the stability of different labeled estrogens under the conditions of ER-assay. Placental cytosols [8] as well as cytosols of other tissues such as endometrium [9, 10], ovary [11] or mammary carcinomas [12] have been reported to contain significant amounts of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity. Conversion of labeled estradiol to estrone during incubation for ER-quantification would diminish the amount of labeled estradiol thus leading to errors in ER-concentrations, as estrone has only about 10% of estradiol's binding activity [13].

17-Hydroxysteroid Dehydrogenases↗
PubMed1983

[Pregnancy and hyperprolactinemia].

After endocrinological and radiological evaluation of a hyperprolactinemia 13 patients became pregnant under bromocriptine therapy. In two of these patients a selective adenomectomy was performed by the transphenoidal route because of a prolactin (PRL) secreting adenoma. In 12 patients the pregnancy was not complicated. The serum PRL levels were different but mostly in a normal range. The control of x-ray and visual field in patients with a rapid increase of the PRL levels did not result in a tumor recurrence. After a normal course of the serum PRL concentrations one patient with a microadenoma developed suddenly a chiasma syndrome in the 31th week of gestation. The further evaluation resulted in a pituitary tumor with suprasellar extension. The discrepancy between the radiological result and the normal serum PRL levels was explained by a hemorrhage into the adenoma. After the operation the chiasma syndrome was reversible within a short period. Altogether, the course of the pregnancies was not complicated. We did not see fetal malformations. Post partum the sella x-ray of all patients did not reveal any significant changes so far.

Adenoma↗
PubMed1983

Methyl 17 beta-carboxyester derivatives of natural and synthetic glucocorticoids: correlation between receptor binding and inhibition of in vitro phytohaemagglutinin-induced lymphocyte blastogenesis.

Several methyl 17 beta-carboxyester derivatives of natural and fluorinated glucocorticoids were synthesized in order to compare their potency to compete for [3H]dexamethasone binding sites in human spleen tumour cytosols (as a source of large quantities of white blood cells) with their potency to inhibit phytohaemagglutinin-induced blastogenesis of normal human peripheral lymphocytes. The 17 beta-carboxylic acids neither show binding activity nor inhibition of blastogenesis. Methylation partially restores the binding capacity and the intensity of this effect depends on the kind of ring substitutions. The sequence of binding potency is identical compared to that of parent steroids and was found to be in the following order: desoxymethasone greater than dexamethasone greater than corticosterone greater than cortisol greater than progesterone greater than 17-hydroxyprogesterone. The phytohaemagglutinin-induced stimulation of [3H]thymidine incorporation resembles the order of binding potency. The methyl 17 beta-carboxyester derivatives of progesterone, 17-hydroxyprogesterone and betamethasone are inactive. The N-benzyl 17 beta-carboxamide analogs of dexamethasone and betamethasone behave like their corresponding carboxyesters, suggesting an important influence of the side chain conformation of 17 beta-carboxyl derivatives on glucocorticoid receptor binding.

Binding, Competitive↗
PubMed1983

Comparison of [3H]oestradiol and [125I]oestradiol as ligands for oestrogen receptor determination.

The newly available ligand [16 alpha-125I]3,17 beta-oestradiol was investigated for its suitability for routine oestrogen receptor determinations. Unlabeled 16 alpha-iodo-oestradiol was synthesized. No difference in the relative binding affinity to human uterine oestrogen receptor could be demonstrated, but unlabeled as well as labeled 16 alpha-iodo-oestradiol do not bind to serum sex hormone binding globulin. At 0--4 degrees C [3H]oestradiol reaches, when incubated with oestrogen receptor its equilibrium after 3 h, [125I]oestradiol after 9 h. In 100 human mammary tumour cytosols oestrogen receptor concentrations were determined using either [3H]oestradiol or [125I]oestradiol. The mean Kd-values obtained were 0.5 +/- 0.3 nmol/l using [3H]oestradiol and 0.42 +/- 0.25 nmol/l for [125I]oestradiol. For the linear regression (independent variable [3H]oestradiol, dependent variable [125I]oestradiol) the following sample estimates were obtained: n = 100, r = 0.982, yi = 3.04 + 1.00035 x. For a 0.95 probability of confidence it can be stated that the sample estimates are indeed comparable according to the criteria of the two ligands.

Binding, Competitive↗
PubMed1982

Steroid hormone receptors in human melanoma.

Human melanomas were investigated for the presence of high-affinity estrogen-, gestagen-, and glucocorticoid-binding proteins. A statistically significant difference was found for mean estrogen receptor (ER) concentrations in melanomas of male versus female origin: female origin 37.6 (0-107) fmol/mg protein, male origin 3.9 (0-8.3) fmol/mg protein. No significant difference between sexes was found for gestragen receptors: 41.5 (0-194) fmol/mg protein for melanomas of female origin versus 99 (0-362) fmol/mg protein for male. Sucrose density gradient analyses revealed specific binding for both receptor types in the 4-5 S region as well as in the 8 S region. The binding affinities were in the same order of magnitude as reported for receptors found in typical steroid target organs. No significant difference in receptor values depending on sex was found for the glucocorticoid receptor: 19.2 (0-43) fmol/mg protein.

Centrifugation, Density Gradient↗
PubMed1982

Estradiol and progesterone binding components in the cytosol of normal human fallopian tubes.

The in vitro binding of labeled estradiol and R5020 to receptor proteins from human fallopian tube cytoplasmic fractions has been studied. Both compounds give rise to two separate peaks in density gradient analysis experiments under low ionic strength conditions: a "8 S" steroid-hormone-specific peak and a "4 S" peak accounted for by non-specific binding. The receptor molecules were further characterized by a competition studies, electrophoretic technique and gel chromatography. The receptor content for both steroid hormones varied throughout the menstrual cycle. The estradiol and progesterone receptor concentration were highest during the proliferative phase and were very significantly lower in the second half of the menstrual cycle. Furthermore measurement of both receptors in the cytosol revealed differences among the anatomical segments of the fallopian tube. The highest estradiol and progesterone binding could be detected in the ampullary region, significantly lower levels of estradiol and progesterone receptor were seen in the infundibulum and the isthmus.

Binding, Competitive↗
PubMed1982

Estradiol and progesterone receptor concentrations and 17 beta-hydroxysteroid-dehydrogenase activity in estrogen-progestin stimulated endometrium of women with gonadal dysgenesis.

Four hypergonadotrophic women between 25 and 37 years of age with gonadal dysgenesis were treated sequentially with estrogens and a progestin. The hormonal environment induced by this therapy was similar to that of ovulating women, as demonstrated by serum levels of estradiol, endometrial histology and pituitary gonadotropin secretion before and after LH-RH double stimulation. The concentrations of estradiol and progesterone receptors (ER and PR) and the activity of the 17 beta-hydroxysteroid-dehydrogenase (17 beta-HSD) were determined in endometrial curettings obtained from the above patients at 5 different days of their 28-day artificial cycles. The results were correlated to the histology of the endometrium and the serum concentrations of estradiol at the corresponding days of the cycle. The cytoplasmic ER and PR concentrations in the endometrium were 3-6 times higher during the estrogen than progestin phase of the induced endometrial cycle. For the activity of the 17 beta-HSD, the contrary was the case, being 6-10 fold higher during the progestin phase. A 22-day administration of estrogens only did not lead to a rise in enzyme activity or decrease in receptor content as observed under progestin influence after day 14. Since ER and PR concentrations and 17 beta-HSD activities were similar to those in the endometrium of normally ovulating women, these results confirm experimentally the present concept concerning the dependence of the cytoplasmic ER and PR content and 17 beta-HSD activity on female sex hormone action.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1982

Synthesis of a new disulfide affinity adsorbent for purification of human uterine progesterone receptor.

For purification of the human uterine progesterone receptor, an affinity adsorbent was synthesized in which the specific ligand (16 alpha-ethyl-3-oxo-19nor-androst-4-ene 17 beta-carboxylic acid) was bound to derivatized celulose using a disulfide-group-containing spacer. The purified receptor protein, isolated by reductive cleavage of the disulfide bond, bound the synthetic gestagen R5020 with high affinity (Kd 12.2 nmol/l). The affinity gel was highly efficient. A 24000-fold purification of progesterone receptor with a recovery of 40% could be achieved in a single step within 6 h. By means of dodecyl sulphate/polyacrylamide gel electrophoresis two main polypeptides with molecular weights of about 43000 and 108000 could be demonstrated.

Adsorption↗
PubMed1982

The effects of chlorotrianisene (Tace) of kinetics of 3H-testosterone metabolism in patients with carcinoma of the prostate.

Alterations in the metabolism of testosterone and plasma levels of testosterone, luteinising hormone (LH), follicle stimulating hormone (FSH), prolactin and oestradiol were studied in 6 patients with newly diagnosed prostatic carcinoma before and during treatment with chlorotrianisene at a daily dosage of 48 mg for 14 days. Parameters of plasma kinetics were determined according to the single injection technique and the 2-compartment model, and the plasma hormones by radioimmunoassay. Chlorotrianisene altered neither plasma levels of testosterone, gonadotrophins, prolactin and oestradiol, nor metabolic clearance rate, production rate and other kinetic parameters of testosterone. Thus the beneficial effects which have been reported previously cannot be explained by suppression of peripheral testosterone metabolism.

Aged↗
PubMed1981

In vivo studies on the antiandrogenic effects of cimetidine versus cyproterone acetate in rats.

To investigate the antiandrogenic action of cimetidine in vivo, prostatic androgen uptake and metabolism, spermatogenesis, morphology of the prostate and testes, and plasma hormone levels were studied using Sprague-Dawley rats, and the results were compared with the effects of cyproterone acetate or castration. Cimetidine and cyproterone acetate caused significant reduction in the weights of the ventral prostate and testes. The changes of ventral prostate were accompanied by a dose-related epithelial atrophy. No adverse effect on spermatogenesis was observed after treatment with cimetidine at daily doses of 50 mg/kg or cyproterone acetate of 10 mg/kg. Although cimetidine treatment induced a significant decrease in plasma testosterone levels, the uptake of testosterone-3H and its conversion to DHT of the ventral prostate were not inhibited by cimetidine.

Androgen Antagonists↗
PubMed1981

A comparison of cytoplasmic and nuclear estradiol and progesterone receptors in human fallopian tube and endometrial tissue.

Quantitative and qualitative aspects of the in vitro binding of 3H-estradiol and 3H-progesterone to receptor components from human endometrium and fallopian tube cytoplasmic and nuclear fractions were studied. The steroid binding macromolecules formed in vitro could be extracted from nuclei by 0.4 M KCl and detected by glycerol gradient centrifugation. Both estradiol- and progesterone-binding compounds formed only one peak (under high ionic strength conditions) with a sedimentation coefficient of about 4-5 S. The number of cytoplasmic and nuclear binding sites for both estradiol and R5020 varied dramatically throughout the menstrual cycle: the estradiol and progesterone receptor concentrations were highest during the proliferative phase and were very significantly lower in the second half of the menstrual cycle. Furthermore, measurement of both receptors in the cytosol revealed differences among the anatomic segments of the fallopian tube. The highest estradiol and progesterone binding could be detected in the ampullary region; significantly lower levels of estradiol and progesterone receptors were seen in the infundibulum and the isthmus.

Cell Nucleus↗