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Biomedical subjects

H G Friesen

Publications and source records attributed to H G Friesen.

At least 55 records · Page 3Linked to original sources
PubMed1991

Prolactin deficiency in rheumatoid arthritis.

Prolactin and growth hormone were determined from the sera of 48 patients with rheumatoid arthritis (RA) and 23 controls by radioimmunoassay and by the Nb2 lymphoma proliferation bioassay. A highly significant deficiency was found in the bioactivity of circulating prolactin (PRL) in patients with RA, whereas immunoactive PRL was near normal. Only age matched male patients showed significantly lower serum PRL levels by radioimmunoassay. Patients with RA with anemia and high reticulocyte counts had bioactivity of PRL elevated and those with anemia and low reticulocyte counts had a decreased bioactivity of PRL when compared to patients without anemia. Prolactin isolated from the sera of 5 patients with RA showed decreased bioactivity in comparison with PRL separated from 5 sex matched controls. Serum factors capable of enhancing or inhibiting the response of Nb2 cells to ovine PRL were also discovered. Our results indicate that RA is associated with PRL deficiency.

Anemia↗
PubMed1990

Cross-linking of G-proteins to the prolactin receptor in rat NB2 lymphoma cells.

In Nb2 cell membranes, two guanine nucleotide-binding protein (G-protein) species (Mr 43.5 and 46.5 kD) were [32P]-ADP-ribosylated by cholera toxin, while a single protein (Mr 41.5 kD) was [32P]-ADP-ribosylated by pertussis toxin. Immunostaining indicated two immunoreactive prolactin (PRL) receptor moieties of 56 and 64 kD. Cross-linking with ethylene glyco bis[succinimidyl-succinate] (mol. length of 16.1 A) generated a high mol. wt., [32P]-ADP-ribosylated band of 140-160 kD which also showed immunoreactivity with antiserum to the PRL receptor. Other cross-linkers with shorter molecular lengths (8.6 - 11.4 A) were ineffective. These findings indicate that the Nb2 lactogen receptor is complexed with G-proteins and provide evidence for the role of G-proteins in mediating PRL-stimulated mitognesis in Nb2 cells.

Adenosine Diphosphate Ribose↗
PubMed1990

Human prolactin gene expression. The use of an alternative noncoding exon in decidua and the IM-9-P3 lymphoblast cell line.

The prolactin (PRL) gene is normally expressed in the anterior pituitary lactotrope and the decidualized stromal cell of the human endometrium. We have recently described the ectopic expression of the human PRL gene in a B-lymphoblastoid cell line, IM-9-P. The IM-9-P and decidual PRL mRNAs are approximately 150 nucleotides longer than the pituitary transcript. The protein coding sequence of the IM-9-P and decidual PRL cDNAs is identical to the pituitary PRL message, and the 3'-untranslated region (UTR) exhibited a 7-14-nucleotide elongation. The 5'-UTR of IM-9-P and decidual PRL cDNAs revealed an extension of 41 base pairs upstream of the normal transcription start site for the human pituitary PRL gene. This is preceded by an additional sequence that is not homologous to the DNA found 5' to the pituitary PRL cap site. Decidual and IM-9-P PRL mRNAs possess identical 5' ends having 5'-UTRs of 83-263 nucleotides longer than that of the pituitary mRNA. The decidual/IM-9-P-specific segment of the 5'-UTR is located as a new 5'-noncoding exon 5-7 kilobase pairs upstream of the human pituitary PRL gene, exon 1. The clonal IM-9-P3 cell line provides a unique and easily manageable resource with which to study decidual specific PRL gene transcription.

Base Sequence↗
PubMed1990

In-gel ligand blotting with 125I-heparin for detection of heparin-binding growth factors.

125I-labeled heparin was used to detect basic fibroblast growth factor (bFGF) in crude tumor cell extracts after separation by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. 125I-labeled heparin bound avidly to native recombinant bFGF immobilized on nitrocellulose and eluted with 1.5-2.0 M NaCl. However, Western transfer of bFGF to nitrocellulose after SDS-polyacrylamide gel electrophoresis destroyed heparin-binding ability. In contrast, bFGF was detected by incubation of the polyacrylamide gels directly with 125I-labeled heparin in a gel overly technique. Heparin affinity and NaCl elution pattern from bFGF in gel were similar to those observed for native bFGF spotted on nitrocellulose. This procedure permitted detection of bFGF in crude extracts of a human astrocytoma cell line. In view of the rapid growth of the heparin-binding fibroblast growth factor gene family, this technique should prove useful for the rapid and sensitive detection of other heparin-binding growth factors.

Blotting, Western↗
PubMed1990

The role of G-proteins in the mitogenesis of rat lactogen-dependent and lactogen-independent Nb2 lymphoma cells.

The expression of guanine nucleotide-binding proteins (G-proteins) was compared in two clonal lines of rat Nb2 node lymphoma cells, the lactogen-dependent Nb2-11C line and the lactogen-independent Nb2-Sp (spontaneous) line. Both cell lines expressed mRNA transcripts for the G-protein species Gs alpha [1.85 kilobases (kb)], Gi2 alpha (2.35 kb), Go alpha (4.1-4.5 kb), and Gi3 alpha (3.5 kb). Gi1 alpha was not detected. ADP ribosylation in the presence of activated cholera or pertussis toxins and [32P]NAD demonstrated the presence of G-proteins in the membrane fractions of both lines. The cholera toxin substrates consisted of two proteins (mol wt, 46.5 and 43.5 kD), while a single protein (mol wt, 41.5 kD) was ADP ribosylated by pertussis toxin. Surprisingly, the cholera toxin-sensitive proteins (Gs) were at least 20-fold less abundant in the Nb2-Sp cells than in the Nb2-11C cells. Since Gs and Gi2 are associated with the adenylate cyclase system and the regulation of intracellular cAMP, the effects of the cAMP analog, (Bu)2cAMP (dbcAMP), on Nb2-11C and Nb2-Sp cell growth were examined. dbcAMP (100 microM) completely inhibited the growth of lactogen-dependent Nb2-11C cells. The inhibitory effect of dbcAMP was exerted at an early point in the cell cycle, as it also inhibited PRL-stimulated c-myc expression measured 3 h after addition of the mitogen. In contrast, dbcAMP had only minor inhibitory effects on lactogen-independent Nb2-Sp cells, increasing their doubling time from 20 to 30 h and slightly reducing their density at confluence. The inhibitory effect of dbcAMP on both cell lines was reversible. Nb2-11C cells resumed growth after a lag period of approximately 3 days. The recovered cells did not arise from selection of a cAMP-resistant subpopulation, since both they and normal untreated Nb2-11C cells remained equally sensitive to dbcAMP. Similarly, Nb2-Sp cells resumed their normal doubling time upon removal of dbcAMP. The observation that the lactogen-independent Nb2-Sp cell line contained 20-fold less cholera toxin-sensitive Gs protein provides circumstantial evidence that dysfunction of the adenylate cyclase system may be implicated in the autonomous growth of these cells. This possibility is strengthened by the observation that Nb2-Sp cells are markedly less sensitive than the Nb2-11C clone to the growth inhibitory effects of an exogenous cAMP analog.

Adenosine Diphosphate Ribose↗
PubMed1990

Molecular cloning and expression of rat placental lactogen-I complementary deoxyribonucleic acid.

A full-length cDNA clone for rat placental lactogen I (rPL-I) has been isolated from a phage lambda gt11 library containing cDNA synthesized from day 11 rat placental mRNA. By Northern blot analysis the rPL-I cDNA clone hybridizes to a 1.0-kilobase placental mRNA and appears as early as day 10 of gestation. Maximal expression of this mRNA was observed in day 11 and 12 placenta, and faint hybridization of the rPL-I cDNA was also detected in day 18 to term placenta. In contrast, the mouse clone hybridized to mRNA for mouse PL-I (mPL-I) only in day 10 mouse placenta (9). In vitro translation of rPL-I mRNA produced by transcription of the cDNA template yielded a 27-kDa polypeptide the size of the expected precursor protein which was immunoprecipitated by a monoclonal antibody to rPL-I. The rPL-I cDNA nucleotide sequence has been determined. The sequence is very similar to that for mPL-I and contains an open reading frame encoding a polypeptide of 230 amino acids compared to 224 for mPL-I. Comparison of the predicted primary translation product of rPL-I mRNA with that of mPL-I mRNA revealed that rPL-I shares 73% identity to mPL-I at the amino acid level. The predicted rPL-I protein shares 41% amino acid identity with rPL-II precursor, 24% with rat prolactin-like protein A, 26% with rat prolactin-like protein B, and 31% with rat PRL. In situ hybridization studies indicated that mRNA for rPL-I was present in a few rapidly dividing cells as early as day 8 of gestation, and by day 9 could be localized to giant cells which surround the conceptus.

Amino Acid Sequence↗
PubMed1990

Expression of insulin-like growth factor-I and insulin-like growth factor-binding protein-1 in the rat uterus during decidualization.

Decidualization of the uterus involves proliferation and differentiation of uterine cells. The effects of decidualization on uterine expression of insulin-like growth factor-I (IGF-I) and IGF-binding protein-1 (IGFBP-1) have been examined in the hypophysectomized-ovariectomized (hypox-ovx) rat and the pituitary-intact (ovx) rat. Decidualization was induced by uterine stimulation of animals treated with a combination of 17 beta-estradiol and progesterone. The patterns of change in uterine IGF-I mRNA and IGFBP-1 mRNA abundance were similar to hypox-ovx rats, hypox-ovx rats replaced with GH and T4, and ovx rats. The changes in IGF-I mRNA abundance were temporally related to 17 beta-estradiol injections. IGFBP-1 mRNA was undetectable early in the decidualization process and reached maximal levels on day 6. Mechanical separation of the deciduoma tissue from the underlying myometrium revealed that the deciduoma tissue was depleted in IGF-I mRNA, while the majority of the IGFBP-1 was located in the deciduoma tissue. The in situ hybridization technique was used to localize IGF-I and IGFBP-1 mRNA in the decidualized uterus. The majority of the IGF-I expression was localized to the outer stroma and smooth muscle cell layer, whereas IGFBP-1 mRNA was detected in uterine epithelial cells and stromal glands. These experiments demonstrated that uterine IGF-I and IGFBP-1 expression during the process of decidualization are pituitary independent. Furthermore, our observations support the hypothesis that the expression of IGFBP-1, a protein capable of inhibiting the mitogenic activity of IGF-I, in deciduoma tissue may inhibit paracrine IGF-1 actin and allow for the differentiation of stromal tissue.

Animals↗
PubMed1990

Expression of rat prolactin-like protein B in deciduoma of pseudopregnant rat and in decidua during early pregnancy.

The rat PRL-like protein-B (rPLP-B) complementary DNA (cDNA), originally cloned from a late term placental library, hybridizes to transcripts in the deciduoma tissue artificially produced in pseudopregnant rats. The expression of rPLP-B in deciduoma is first observed 48 h (pseudopregnancy day 7) after the deciduogenic stimulus and increases to a maximum by 96-120 h (pseudopregnancy day 9-10). In situ hybridization studies show that rPLP-B hybridizes specifically to the antimesometrial cells of deciduoma tissue in day 9 pseudopregnant rats and to the homologous cells of the decidua that surround the embryo-trophoblastic structure at day 9 of pregnancy. A temporal study on the expression of rPLP-B during pregnancy shows that rPLP-B is concomitantly expressed by the decidual cells of maternal origin and the cytotrophoblast of fetal origin around day 13 of pregnancy.

Animals↗
PubMed1990

Circulating fibroblast growth factor-like substance in familial multiple endocrine neoplasia type 1.

Basic fibroblast growth factor (bFGF) is a potent endothelial cell mitogen found in a variety of normal and tumor tissues. Basic FGF lacks a classical signal sequence, and it is not clear how it is released from cells. bFGF or bFGF-like activity has not been previously demonstrated in plasma. In an earlier study we showed increased mitogenic activity for parathyroid-derived epithelial and mesenchymal cells in plasma of subjects with familial multiple endocrine neoplasia type 1 (FMEN1). In the present study we examined the growth-promoting activity of normal and FMEN1 plasmas [applied to heparin-Sepharose (HS) columns] in parathyroid-derived cloned endothelial cells. FMEN1 plasma HS-adsorbed activity exceeded normal plasma HS-adsorbed activity in 6 of 8 FMEN1 plasma samples. Peak (FMEN1 plasma) HS-adsorbed activity eluted with 0.1-0.3 M NaCl, was completely neutralized by specific antibodies against bFGF, and had an apparent mol wt of 110 kD. Active fractions from FMEN1 plasma prepared by gel filtration in 7 M urea displayed apparent mol wt of about 14-16 kD and showed increased apparent affinity for HS; recovered activity appeared principally in the 3.0-M NaCl eluate. Using a sensitive two-site immunoradiometric assay for bFGF we found 0.4 ng/mL bFGF-like immunoreactivity in the highly purified 3.0-M NaCl eluate from a HS column to which the active components from gel filtration of FMEN1 plasma in 7 M urea were applied. These results imply that bFGF or closely related factors circulate in FMEN1.

Adult↗
PubMed1990

Presence of galanin-like immunoreactivity in nontumorous corticotrophs and corticotroph adenomas of the human pituitary.

Galanin is a 29-amino acid neuropeptide widely distributed in the central nervous system. Galanin-like immunoreactivity (galanin-LI) was investigated in 23 nontumorous human adenohypophyses and 27 pituitary adenomas. Galanin-LI was demonstrated by immunohistochemistry on formalin-fixed paraffin-embedded sections, using the avidin-biotin-peroxidase complex method. All 23 nontumorous pituitaries showed the presence of galanin-positive cells which were similar to the corticotrophs in shape, size, histological features, and distribution. Immunoreactivity based on the study of mirror sections was found to be present in the cytoplasm of corticotrophs, indicating that galanin-LI colocalizes with ACTH. Crooke's cells and basophilic cells spreading to the posterior lobe (basophil invasion) were also positive for galanin. No galanin-LI was seen in lactotrophs of the human pituitaries, including 4 estrogen-treated men and 4 pregnant women. Varying numbers of tumor cells in 13 of 18 corticotroph adenomas were positive for galanin. Galanin-LI and ACTH were coexpressed in the cytoplasm of the same adenoma cells. In 19 pituitary adenomas composed of cells other than corticotrophs, no galanin-LI was noted. This study is the first report providing evidence of the presence of galanin-LI in corticotrophs of the human pituitary.

Adenoma↗
PubMed1990

Messenger RNA stabilization accounts for elevated basic fibroblast growth factor transcript levels in a human astrocytoma cell line.

Basic fibroblast growth factor (bFGF) is a potent autocrine and paracrine mitogen for cells of mesodermal origin. Although the protein is present in substantial amounts in a variety of tissues, the level of mRNA is undetectable in most normal tissues. This has led to speculation that bFGF mRNA is very unstable, but the half-life of this mRNA has not been described. A number of mRNAs encoding growth factors and growth-related proteins are known to be short-lived and posttranscriptionally regulated. In the present study we have examined the half-life of bFGF mRNA in two human tumor cell lines, which contain high (U87-MG) and low (T98-G) steady state bFGF mRNA levels. The half-life of bFGF mRNA, determined after transcriptional arrest with actinomycin-D, was approximately 10 min in T98-G cells, but was extended to 120 min in the presence of cycloheximide. In contrast, bFGF transcripts in U87-MG cells were very stable with a half-life considerably greater than 5 h. This was not attributable to a general stabilization of mRNA in the U87-MG line, since the half-life of c-myc mRNA in the two cell lines was similar (10 and 15 min in T98-G and U87-MG, respectively). Cycloheximide had no effect on the steady state level of bFGF in U87-MG cells. These findings suggest that posttranscriptional processes play an important role in the regulation of bFGF transcript levels and demonstrate that loss of posttranscriptional regulation could contribute to elevated bFGF expression in some tumors.

Astrocytoma↗
PubMed1989

Estrogen induction of galanin synthesis in the rat anterior pituitary gland demonstrated by in situ hybridization and immunohistochemistry.

The distribution of galanin messenger (mRNA) and galanin-like immunoreactivity (Gal-LI) in the anterior and posterior pituitaries of control and estrogen-implanted female rats was determined by in situ hybridization and immunohistochemical methods. In control ovariectomized animals galanin mRNA was undetectable in the posterior, intermediate and anterior pituitary. However, 4 days after implantation with 10 mg of diethylstilbestrol, galanin mRNA was clearly present in the anterior pituitary, but not in the posterior or intermediate lobe. By immunohistochemistry Gal-LI was readily visualized and detected in the posterior lobe, but clearly undetectable in cells of the intermediate and anterior pituitary lobes of control animals. After estrogen administration numerous cells exhibiting intense Gal-LI were evident in the anterior lobe, while Gal-LI remained unchanged in the intermediate and posterior lobes. These results indicate that in control animals galanin is stored, but not synthesized, in the posterior pituitary and that after estrogen administration galanin production is substantially increased in the anterior pituitary. We conclude that the expression of galanin in the anterior pituitary is regulated by estrogen and suggest that galanin may be a pituitary hormone.

Animals↗
PubMed1989

Verification of NB2 lymphoma cell bioassay for the measurement of plasma and pituitary prolactin in the Mongolian gerbil (Meriones unguiculatus).

Serum and pituitary glands were taken from male Mongolian gerbils which had received bromocriptine implants, ether stress or no treatment (controls). Pituitary prolactin (Prl) and growth hormone (GH) mRNA were analyzed by Northern hybridization using rat cDNA probes. Pituitary and plasma Prl content were analyzed with the Nb2 lymphoma cell growth bioassay. These assays were sensitive to the decreases in Prl caused by bromocriptine and the elevation of Prl caused by ether stress. The inhibition of pituitary and plasma Prl levels by bromocriptine correlated with a marked inhibition of pituitary Prl mRNA content. In contrast, levels of GH mRNA did not change with treatment, indicating that gerbil GH does not contribute to the lactogenic activity measured in the Nb2 lymphoma cell bioassay. The results indicate that this bioassay is suitable for the measurement of gerbil pituitary and plasma Prl.

Animals↗
PubMed1989

Phorbol ester stimulates prolactin release but reduces prolactin mRNA in the human B-lymphoblastoid cell line IM-9-P3.

The phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) stimulated prolactin (PRL) release from the PRL producing human B-lymphoblastoid cell line IM-9-P3 within 30 min with an EC50 of 5 x 10(-9) M. Increased release was entirely attributable to a loss from intracellular PRL pools. No change in hPRL mRNA was observed during 8 h of exposure to TPA. Prolonged exposure of the cells to 2 x 10(-7) M TPA, however, led to a maximal reduction of hPRL mRNA levels after 24 h and a subsequent recovery by 72 h. Secretory rates followed a corresponding kinetic. The relative abundance of c-myc mRNA was not affected, although a persistent inhibition of cellular proliferation occurred upon chronic exposure to TPA. The addition of dibutyryl cAMP caused a minor transient increase in hPRL secretion by 35% after 1 h.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Prolactin (PRL) mRNA from human decidua differs from pituitary PRL mRNA but resembles the IM-9-P3 lymphoblast PRL transcript.

The expression of the human prolactin (hPRL) gene is normally restricted to the anterior pituitary and the decidualized endometrium of the uterus. The human B-lymphoblastoid cell line IM-9-P3 ectopically expresses a PRL mRNA which is about 150 nucleotides larger than its pituitary counterpart even though the mature protein products appear identical. In the present study we show that human decidual and IM-9-P3 PRL mRNAs are similar in size, both being elongated relative to the pituitary transcript. The size difference persisted after removal of the 3' end poly(A) tract, whereas the PRL precursors synthesized in a cell-free translation system using mRNAs from the three tissues showed identical apparent molecular weights upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The elongation could therefore not be attributed to differences in the protein coding region or in the degree of polyadenylation and is suggested to reside in the 5' untranslated region of the molecule.

Decidua↗
PubMed1989

Primary culture of teleocalcin cells from rainbow trout corpuscles of Stannius: regulation of teleocalcin secretion by calcium.

This report describes a series of studies on the regulation of teleocalcin secretion by primary cultures of rainbow trout corpuscles of Stannius, endocrine glands believed to be unique to bony fishes. Teleocalcin release by these cultured cells was stimulated specifically by calcium in a dose-related fashion. Magnesium did not mimic the effects of added calcium and varying the osmotic pressure had no effect on hormone release. The addition of either ethyleneglycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) or cobalt chloride blocked the stimulatory effects of added calcium, whereas the calcium ionophore A23187 mimicked the effects of calcium on hormone release. Mammalian and piscine pituitary hormones (prolactin, growth hormone and gonadotrophic hormone) had no effect on teleocalcin secretion. Inconclusive results were obtained with the calcium channel blockers, verapamil and nifedipine. The results are discussed in relation to calcium-regulated secretion of calcitonin and parathyroid hormone, as well as the known physiological effects of teleocalcin in fish.

Animals↗