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V Isomaa

Publications and source records attributed to V Isomaa.

At least 37 records · Page 2Linked to original sources
PubMed1992

Immunohistochemical study of the human 17 beta-hydroxysteroid dehydrogenase and steroid receptors in endometrial adenocarcinoma.

17 beta-Hydroxysteroid dehydrogenase (17HSD) and estrogen (ER) and progestin (PR) receptors were analyzed immunohistochemically in tissue specimens of 66 patients with endometrial adenocarcinoma. Plasma steroid concentrations were correlated to immunohistochemical data. 17HSD was detected in 48% of the specimens and was stained in the cytoplasm of epithelial cells. The tissues were characterized by a heterogeneous staining pattern for 17HSD. In some patients, intensively stained epithelial cell clusters were seen, indicating that local factors were responsible for the expression of the protein. Poorly differentiated adenocarcinoma specimens tended to have no 17HSD more frequently than did well or moderately differentiated tissues. ER and PR were detectable in 24% and 28% of patients, respectively, and were localized in the nuclei of epithelial and stromal cells. There was a significant correlation between 17HSD and PR staining and an inverse correlation between plasma progesterone concentrations and 17HSD staining. This is contrary to the data obtained with normal endometrium. The main reason for this inverse relation between endometrial 17HSD staining and plasma progesterone concentrations was that, in some postmenopausal patients with low plasma progesterone concentrations, intense staining for 17HSD was detectable in the endometrial carcinoma specimens. This indicates a major difference in the regulation of 17HSD expression in endometrial adenocarcinomas, compared with normal tissues of premenopausal women.

17-Hydroxysteroid Dehydrogenases↗
PubMed1992

Immunological analysis of 17 beta-hydroxysteroid dehydrogenase in benign and malignant human breast tissue.

The expression of 17 beta-hydroxysteroid dehydrogenase (17-HSD) enzyme protein was studied in benign and malignant human breast tissue using the time-resolved immunofluorometric assay (IFMA), immunoblotting and immunohistochemistry. The presence and distribution of estrogen and progestin receptors was also analyzed immunohistochemically. Cytosolic 17-HSD concentrations in malignant breast specimens were highly variable (less than or equal to 0.2-311 ng/mg protein). As was previously found for the placental enzyme, the molecular weight of the 17-HSD expressed in malignant breast tissue was 35 kDa, estimated following polyacrylamide gel electrophoresis and immunoblotting. The cellular distribution of 17-HSD was further studied by immunohistochemistry. Immunostaining for 17-HSD was observed in 71% of the benign breast lesions (fibroadenomas and cases of mastopathia chronica) and in 47% of the cancer specimens (intra-ductal carcinomas, invasive ductal carcinomas). In benign lesions, the staining was exclusively localized in the cytoplasm of epithelial cells, with no immunoreactivity in the stromal cells. The staining in the cancer specimens was also detected only in the cytoplasm of malignant epithelial cells. A strong or moderate expression of 17-HSD was related to the presence of PR in the specimen (chi 2 = 4.657, p = 0.031). However, the expression of PR was not a prerequisite for expression of 17-HSD in all the cancer specimens. Our data suggest that, in addition to the reported regulation of 17-HSD by progestins, other factors are also involved in this process in breast tissue.

17-Hydroxysteroid Dehydrogenases↗
PubMed1992

Immunohistochemical detection of human estrogen receptor with region D-specific antipeptide antibodies.

To study the possibility of using antipeptide antibodies for the immunohistochemical determination of human estrogen receptors (ER), three peptides corresponding to the putative major antigenic regions of the human ER (Met12-Leu26, or ERP1; Thr227-Gln267, or ERP2; Leu256-Gly275, or ERP3) were used to produce site-specific rabbit polyclonal antipeptide antisera. High titer antibodies were obtained against all the peptides used, as judged by time-resolved fluoroimmunoassay. The antibodies against region D (ERP3) specifically immunoprecipitated the ER proteins in vitro, as did the antiERP2 antibodies to a much smaller extent. With one of the region D-specific antibodies (antiERP3 Ab2) ER could also be immunohistochemically detected. When benign and malignant human breast and normal endometrial tissues were used, the immunohistochemical staining observed with these antipeptide antibodies correlated well with the staining obtained with an established method. Thus, the results reported here show that this part of region D in ER is a potential antigenic epitope for the production of site-specific antibodies against ER. Antipeptide antibodies produced against this region can be used to immunolocalize the ER in various normal and pathological human tissues.

Breast Neoplasms↗
PubMed1992

Bovine uterine, cervical and ovarian androgen receptor concentrations. Correlation with estrogen and progesterone receptor concentrations.

Bovine cytosol androgen receptor (ARC) concentrations were examined simultaneously in various regions of the uterus and in ovarian tissues of cows, and were related to cytosol estrogen (ERC) and progesterone receptor (PRC) concentrations and circulating steroid levels. ERC concentrations were 3-7-fold and PRC concentrations 13-29-fold those of ARC in bovine endometrial and myometrial tissues. When serum progesterone levels were low, both endometrial and myometrial ARC, endometrial ERC, and endometrial and myometrial PRC concentrations were higher (p < 0.05) than those observed during higher progesterone concentrations. Because serum 5 alpha-dihydrotestosterone (5 alpha-DHT) concentrations were higher during the luteal phase, it is possible that ARC was down-regulated by this natural ligand at this phase of the cycle. There were no differences between uterine horns in endometrial or myometrial ARC concentrations. Bovine cervical and ovarian stromal tissue also contained ARC, and the concentrations were about the same as in the endometrium and the myometrium. The relative binding affinities (RBAs) of some steroid hormones towards ARC in vitro were: the synthetic compound R1881 (146%), 5 alpha-dihydrotestosterone (100%), testosterone (75%) while estradiol-17 beta, progesterone and dexamethasone had lower RBAs (2, < 1, < 1% respectively). Cytosol androgen receptor concentrations correlated significantly with cytosol progesterone (PRC) and estrogen receptor (ERC) concentrations, both in the endometrium and myometrium. These data show that androgens, such as 5 alpha-DHT, may participate the endocrine regulation of bovine reproductive tissues.

Animals↗
PubMed1991

Immunohistochemical localization of 17 beta-hydroxysteroid dehydrogenase in the human endometrium during the menstrual cycle.

Immunoaffinity-purified polyclonal anti-rabbit antibody against human placental 17 beta-hydroxysteroid dehydrogenase (17HSD) was used to localize 17HSD in frozen sections of 21 human endometrial tissue specimens, taken at different stages of the menstrual cycle, and in the human placenta. The presence and distribution of estrogen and progesterone receptors were also analyzed in endometrial specimens using commercial immunohistochemical techniques. In addition, 17HSD was localized by immunoelectron microscopy in the endometrium and the placenta. In the endometrium, immunostaining of 17HSD appeared in the cytoplasm of surface epithelial and gland cells during the early and midluteal phase. During the late luteal phase, it gradually disappeared. No immunostaining was observed in the endometrium during the follicular phase of the menstrual cycle. The changes in staining intensity of 17HSD were associated with changes in the concentration of serum progesterone as judged by radioimmunoassay. An apparent inverse correlation between 17HSD expression and the concentrations of estrogen and progesterone receptors was observed. These results strongly support the concept that progesterone induces an increase in the amount of 17HSD, in the glandular and surface epithelial cells of the human endometrium. In the human term placenta, 17HSD immunostaining was detected exclusively in the cytoplasm of syncytiotrophoblasts. In immunoelectron microscopic studies of the endometrium and placenta, 17HSD staining was observed in the cytoplasm and it was associated with cytoplasmic membranes unrelated to the endoplasmic reticulum.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

Progestin induction of 17 beta-hydroxysteroid dehydrogenase enzyme protein in the T-47D human breast-cancer cell line.

Steroid regulation of 17 beta-hydroxysteroid dehydrogenase (17-HSD) was studied in the T-47D human breast-cancer cell line, using a radioimmunoassay. In addition, 3 mRNA species (2.4, 1.4, and 0.9 kb) specific for the enzyme were shown to be present in these cells. All the synthetic progestins tested (ORG 2058, R5020, medroxyprogesterone acetate) significantly increased the immunoreactive enzyme protein concentration, while other types of steroids, such as testosterone, oestradiol and dexamethasone, were ineffective. The progestin-specific induction of 17-HSD was dose-related and was maximum in about 5 days. An antiprogestin, RU 486, when used in combination with synthetic progestins, blocked the progestin-induced increase of 17-HSD concentration very effectively. A good correlation was observed in the different experiments between the enzyme activity and the immunoreactive 17-HSD concentration. We conclude that progestins induce 17-HSD in T-47D cells and that the induction occurs via an increased accumulation of enzyme protein.

Breast Neoplasms↗
PubMed1990

Immunological measurement of human 17 beta-hydroxysteroid dehydrogenase.

Human placental 17 beta-hydroxysteroid dehydrogenase (17-HSD) was purified to apparent homogeneity using ammonium sulfate precipitation and chromatography on Red-Agarose and DEAE-Sepharose columns. Electrophoresis on polyacrylamide gels under denaturing conditions and using silver staining showed a single protein with an apparent molecular weight of 37,800. Antibodies to the purified protein were raised in rabbits and were found by immunoblotting to be specific to 17-HSD. A sensitive radioimmunoassay was established using 125I-labeled 17-HSD as a tracer, an appropriate dilution of the antibody, and a kaolin-coupled double antibody for separating the antibody-bound and free fractions. The detection limit of the assay was approximately 150 pg/tube (1.5 micrograms/l). The cytosol fraction (105,000 g) of term placental tissue contained approximately 0.7 mg of 17-HSD per gram of protein, and the concentrations of 17-HSD measured by immunoassay and enzymatic activity proved to be strictly parallel in different partly purified placental preparations. The supernatants from centrifugations of human endometrial homogenates at 800 g and 105,000 g (after detergent treatment) displayed cross-reactivity with the antibody. The mean concentration of the cross-reacting substance in the radioimmunoassay was 14.1 micrograms/g protein (range 2-62.3) in specimens taken on different days in the cycle. These concentrations showed a significant correlation with the 17-HSD activities measured in the endometrial specimens (r = 0.722, P less than 0.001, n = 21). Mean concentrations of substance were 8.3 micrograms/g protein in endometrial specimens taken during the follicular phase (days 4-12, n = 8) and 22.9 micrograms/g protein during the luteal phase (days 16-22, n = 6) were obtained using the radioimmunoassay. There was excellent parallelism between the competition curves for [125I]iodo-17-HSD with purified 17-HSD standards and placental and endometrial homogenate dilutions. These data strongly suggest that the substance measured in the endometrial specimens was 17-HSD.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

The gene for 17 beta-hydroxysteroid dehydrogenase maps to human chromosome 17, bands q12-q21, and shows an RFLP with ScaI.

The gene encoding human 17 beta-hydroxysteroid dehydrogenase (17-HSD; EC 1.1.1.62) is assigned to chromosome 17 by Southern blotting analyses of panels of human x rodent somatic cell hybrids and independently to 17q12-q21 using chromosomal in situ hybridization. A search for physical linkage between 17-HSD and the proto-oncogenes. THRA1 and ERBB2 (both reported to be located in this region of chromosome 17) was performed by pulsed-field gel electrophoresis (PFGE) using several rare-cutting restriction endonucleases. Because all three genes hybridized to DNA fragments of different lengths it seems unlikely that the gene for 17-HSD is located very close to THRA1 and ERBB2. Further evidence for this assumption was obtained from the absence of any coamplification of the 17-HSD gene in 9 breast tumors with amplification of the ERBB2 gene. Analyses of Southern blots of ScaI-digested DNAs from unrelated individuals from Northern Finland revealed a relatively infrequent diallelic restriction fragment length polymorphism, the allele frequencies of which were 0.04 (A1) and 0.96 (A2).

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

Bovine steroid hormone and SHBG concentrations postpartum and during the oestrous cycle.

Changes in consecutive estimates of milk progesterone concentrations and serum steroid hormone and sex hormone-binding globulin (SHBG) concentrations in the postpartum period were examined in Finnish Ayrshire and Friesian dairy cows which were divided according to feeding into a hay group and a silage group. Milk progesterone concentrations rose above 10 nmol/l, indicating the start of ovarian luteal activity, slightly earlier in the silage group (28.4 +/- 8.7 (S.D.) days, n = 19) than in the hay group (33.4 +/- 10.3, n = 28) after calving. Likewise, the first normal oestrous cycles began slightly earlier in cows fed with silage. On the other hand, no differences in the beginning of ovarian luteal activity were observed between the breeds. Serum oestradiol-17 beta, oestrone, testosterone, 5 alpha-dihydrotestosterone (5 alpha-DHT), pregnenolone and progesterone concentrations were fairly unchanged during postpartum anoestrus after uterine involution and before ovarian cyclic activity. After first ovulation, considerable increases in milk and serum progesterone concentrations were observed. The increase was accompanied by elevations in serum pregnenolone and 5 alpha-DHT concentrations. In the late luteal phase, progesterone, 5 alpha-DHT and pregnenolone concentrations rapidly declined, leading to low hormone levels in pro-oestrus. Thereafter, serum pregnenolone and 5 alpha-DHT concentrations slightly increased during the follicular phase. On the other hand, oestradiol-17 beta concentrations were elevated in pro-oestrus and decreased after that, being lowest at met-oestrous. Serum testosterone concentrations appeared to be unchanged during postpartum anoestrus and over the oestrous cycle. Serum SHBG concentrations were unchanged during postpartum anoestrus and over the oestrous cycle, as well as in pregnant animals. The serum SHBG concentrations were about double those found in women with normal menstrual cycles, whereas oestradiol concentrations were much lower. At present, it cannot be explained how the biological effects of oestradiol become evident under such conditions.

Anestrus↗
PubMed1988

Complete amino acid sequence of human placental 17 beta-hydroxysteroid dehydrogenase deduced from cDNA.

cDNA clones for 17 beta-hydroxysteroid dehydrogenase (17-HSD; EC 1.1.1.62) were isolated from a placental lambda gt11 expression library using polyclonal antibodies against placental 17-HSD. The largest cDNA contained 1325 nucleotides, consisting of a short 5'-noncoding segment, a coding segment of 987 nucleotides terminated by a TAA codon, and a 329 nucleotide long 3'-noncoding segment. The open reading frame encoded a polypeptide of 327 amino acid residues with a predicted Mr of 34853. The amino acid sequence of 23 N-terminal amino acids determined from purified 17-HSD agreed with the sequence deduced from cDNA. The deduced amino acid sequence also contained two peptides previously characterized from the proposed catalytic area of placental 17-HSD.

17-Hydroxysteroid Dehydrogenases↗
PubMed1987

Evidence for an androgen receptor in porcine Leydig cells.

Cytosol and nuclear androgen receptor concentrations were measured in freshly prepared and cultured Leydig cells of immature pig testis with exchange assays using [3H]methyltrienolone as labelled ligand. Androgen receptors in Leydig cells had high affinity for [3H]methyltrienolone and steroid binding specificity typical of an androgen receptor. The mean receptor concentrations were 76 fmol/mg protein and 210 fmol/mg DNA for cytosol and nuclei, respectively. In sucrose gradients, cytosol androgen receptors sedimented in the 4 S region. The cells maintained androgen receptors under culture conditions. Exposure of cultured cells to [3H]methyltrienolone (10 nmol/l) resulted in accumulation of androgen receptors in the nuclei with maximal uptake by 1 h. We conclude that methyltrienolone binding sites with characteristics of androgen receptors were identified in both cytosol and nuclei of porcine Leydig cells.

Animals↗
PubMed1986

The predictive value of steroid hormone receptor analysis in breast, endometrial and ovarian cancer.

The predictive value of female sex steroid, estrogen and progesterone, receptor (ER and PR, respectively) assays in breast, endometrial and ovarian cancer is reviewed with emphasis on comparative aspects of these malignant tumors in relation to their hormone dependency. The endocrine etiology of these three tumor types seems to be at least partly different, and so is the expression of these receptors in normal and malignant tissues of the breast, endometrium and ovary. There is a tendency for decreased receptor concentrations and disappearance of these receptors in association with advancement of these malignancies. There is also a decrease in the presence and concentrations of ER and PR in relation to loss of differentiation in breast and endometrial cancer. Receptor analyses have an established position in the selection of patients with advanced breast cancer for endocrine treatment, and they give promise of a similar application in endometrial cancer and in endometrioid cancer of the ovary. It is not clear whether the disease-free interval is related to the presence or concentrations of ER or PR as such in the tumor tissue. There is better survival in breast cancer patients with receptor-positive tumors, which might be due to a response to endocrine treatment. The same seems to be true for patients with endometrial cancer. Future progress in the application of female sex steroid receptor analyses in breast, endometrial and ovarian cancer needs additional controlled clinical trials and more highly developed receptor assays.

Breast Neoplasms↗
PubMed1985

Effect of gestrinone in endometriosis tissue and endometrium.

The effects of gestrinone (R 2323) on endometrial and endometriosis tissue concentrations of cytosol estrogen and progestin receptors and the activity of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) were investigated in 11 patients operated on because of suspected external endometriosis. Serum concentrations of luteinizing hormone, follicle-stimulating hormone, estradiol (E2), progesterone, testosterone (T), and sex-hormone-binding globulin (SHBG) were also investigated. After one control cycle, the patients received 2.5 mg of oral gestrinone twice weekly from the fifth day of the first treatment cycle until the eighth day of the second treatment cycle, the day of operation being day 10. Treatment with gestrinone decreased serum concentrations of T during the second treatment cycle and effected a major decrease in SHBG during both treatment cycles, resulting in highly increased free T and free E2 indices. The effects of gestrinone on the endometrium, a decrease in estrogen and progestin receptors, and induction of 17 beta-HSD are characteristic progestin actions. These parameters remained unchanged in endometriosis tissue. Our data indicate that gestrinone has effects that are typical of androgens and progestins in patients with endometriosis.

17-Hydroxysteroid Dehydrogenases↗
PubMed1985

Nuclear androgen receptors in different stages of the seminiferous epithelial cycle and the interstitial tissue of rat testis.

Testicular androgen receptors were measured with a recently developed exchange assay using [3H]methyltrienolone from samples of interstitial tissue, whole seminiferous tubules, and segments of tubules in different stages of the cycle of the seminiferous epithelium. The hexylene glycol method was used to isolate nuclei and pyridoxal 5'-phosphate for extraction of the androgen receptors. This method proved superior to other techniques employed by our own and other laboratories. As a consequence, higher levels of androgen receptors were detected in seminiferous tubules than previously reported. Androgen receptors in seminiferous tubules and interstitial tissue had high affinity for methyltrienolone (Kd = approximately 3 nM) and steroid binding specificity similar to that of these receptors in other tissues. The concentration of nuclear androgen receptors in whole seminiferous tubules was 670 +/- 100 fmol/mg DNA (mean +/- SE), while that of the interstitial tissue was 1070 +/- 295 fmol/mg DNA. Tubules in stages IX-XII and XIII-I of the epithelial cycle contained significantly more nuclear androgen receptors (900 +/- 170 and 805 +/- 125 fmol/mg DNA, respectively) than those in stages II-VI and VII-VIII (485 +/- 95 and 485 +/- 65 fmol/mg DNA, respectively). These results suggest that there are local differences in androgen receptor concentration along the length of the seminiferous tubule. A high concentration of nuclear androgen receptors was also present in interstitial tissue. Androgen receptors were measurable in cytosol prepared from interstitial tissue, but such measurements were obscured in cytosol from tubules, because of a high capacity binding protein for the 3H-labeled ligand. We conclude that nuclear androgen receptors can be measured in various testicular compartments, including different stages of the seminiferous tubules, using an exchange assay that maximizes recovery. The concentration of nuclear androgen receptors in the tubules varies with the cycle of the seminiferous epithelium.

Animals↗
PubMed1981

In vitro binding to an in vivo effect on the cytosol and nuclear progesterone receptors of various progestins, and their relationship to synthesis of uteroglobin in rabbit uterus.

In vitro binding affinities of various progestins to cytosol and nuclear progesterone receptors of rabbit uterus were determined and correlated with the biological potency of these steroids. In addition, cytosol and nuclear progesterone receptor levels were measured after a 5-day administration of different progestins (0.5 mg/kg daily) with variable biologic activities. The receptor levels were compared with the biological response; the induction of uteroglobin synthesis. Cytosol and nuclear progesterone receptors had identical steroid binding properties (r = 0.98). The correlation between the in vitro binding affinity (cytosol or nuclear) and the in vivo biologic activity of the steroids was good (r = 0.73). After a 5-day treatment with progestins, the nuclear receptor concentration correlated n an inverse manner (r = -0.84) with the uterine fluid uteroglobin concentration. A similar, but slightly weaker correlation (r = -0.81) was also found for the cytosol receptor content and uteroglobin secretion. These data indicate that not only nuclear, but also cytosol progesterone receptor levels decrease in the rabbit uterus during chronic hormone action. Decline in the nuclear progesterone receptor content seemed to occur during treatment with all progestational steroids, while only progestins with high biological potency were capable of decreasing the cytosol receptor content.

Animals↗