bluuebunny/crossref_metadata_2025_split huggingface dataset:
A possible role for D8/PSF-A-like sequences in lactotroph versus somatotroph expression of the human prolactin gene
Authors: Leite V , Cardoso E A , Bock M E , Sobrinho L G , Cattini P A 
Published: December 2004

Abstract
The transcription factor GHF-1/Pit-1 is essential for the expression of GH and prolactin (PRL) by somatotrophs and lactotrophs respectively. However, PRL is not expressed in mature somatotrophs despite the presence of GHF-1/Pit-1. A possible mechanism is the presence of a somatotroph-specific repressor in the 5′-flanking sequences of the PRL gene. The region −3500/−1750 of the human (h) PRL gene is associated with negative regulatory activity and contains an element, designated D8, that resembles repressor PSF-A sequences which are located in the distal upstream region of placental members of the human GH family. An internal deletion of D8 sequences resulted in a significant stimulation of promoter activity in somatotroph GC (P<0·005) and somatolactotroph-like GH3 and GH4C1 cells (P<0·05), but not lactotroph-like 235–1 cells after gene transfer. However, D8 binding was observed by nuclease protection with lactotroph- as well as somatotroph-like cell nuclear protein. Although proteins that bind to the D8 element appear ubiquitous, this element does yield tissuespecific complexes in mobility shift assays. Further, competition studies do not suggest an interaction between GHF-1/Pit-1 and D8 proteins. The hPRL D8 element was inserted upstream of a thymidine kinase promoter and used to transfect pituitary and non-pituitary HeLa cells, to assess intrinsic repressor activity and/or promoter specificity. Although no repression was observed, a significant ninefold increase in expression was observed in HeLa cells (P<0·001) which was at least twofold greater than observed in any of the pituitary cell lines tested. These results implicate D8 in the somatotroph-specific repression of hPRL; however, they also suggest that D8 can act as a stimulator as well as a repressor, depending on the interaction of a ubiquitous D8 factor forming promoter and cell-specific complexes with other elements/factors.
Journal of Endocrinology (1996) 149, 473–483
New insights into zonal differentiation of adrenal autotransplants in the rat: an immunohistochemical study
Authors: Vendeira P , Pignatelli D , Neves D , Magalhães M M , Magalhães M C , Ho M M , Vinson G P 
Published: December 2004

Abstract
Adrenal gland autotransplantation, an interesting model of adrenal regeneration, provides the reconstruction of distinct functional and morphological zonae. An immunohistochemical study of the adrenal gland of adult male rats after autotransplantation and endothelin-1 (ET-1) stimulation was carried out. The technique involved total adrenalectomy and immediate autotransplantation of small adrenal pieces under the skin of the dorsal region. The animals were killed 90 days after the autotransplantation and 1 h after intravenous ET-1 administration. Sections of recovered adrenal grafts were incubated with IZAb, a monoclonal antibody which interacts with an antigen (IZAg) predominantly found in rat adrenal inner zones. Saline-treated control autotransplanted animals showed IZAb immunostaining in almost all adrenocortical tissue, with the exception of small clusters of cells beneath the capsule. ET-1-treated animals exhibited an extended zone devoid of immunostaining and located in the subcapsular area. In addition, ET-1-stimulated animals showed significant increases in aldosterone as well as corticosterone concentrations in plasma. These results revealed that ET-1 stimulated the development of an extended subcapsular zone lacking IZAg expression, an effect that suggests its role in zona glomerulosa induction in these animals.
Journal of Endocrinology (1996) 149, 497–502
Molecular forms of GnRH in three model fishes: rockfish, medaka and zebrafish
Authors: Powell J F F , Krueckl S L , Collins P M , Sherwood N M 
Published: December 2004

Abstract
Three species of fish have become important in the study of reproduction and development. Rockfish are a model for developmental studies of live-bearing perch-like fish, whereas medaka and zebrafish are models for developmental and genetic studies. The forms of GnRH are identified in the brains of each of these fish and in the pituitary of the rockfish to investigate the role of GnRH in reproduction. Here, we report that grass rockfish (Sebastes rastrelliger) have three forms of GnRH in brain extracts as determined by HPLC elution position and RIA. These forms are identified as sea bream GnRH, chicken GnRH-II and salmon GnRH. In contrast, only two forms of GnRH were detected in brain extracts of medaka (Oryzias latipes) and zebrafish (Brachydanio rerio): salmon GnRH and chicken GnRH-II. Rockfish is distinct from medaka and zebrafish in that the most abundant form of GnRH in the rockfish pituitary is sea bream GnRH, whereas this form is absent in the other two fishes. The identification of sea bream GnRH in the rockfish brain and pituitary extracts indicates that the phylogenetic emergence of sea bream GnRH is earlier than the order Perciformes.
Journal of Endocrinology (1996) 150, 17–23
Trophoblastic giant cells of the mouse placenta contain calbindin-D9k but not the vitamin D receptor
Authors: Shamley D R , Veale G , Pettifor J M , Buffenstein R 
Published: December 2004

Abstract
The effects of vitamin D deficiency on the ontogeny of calcium-binding proteins (CaBPs) and the vitamin D receptor (VDR) in the placenta and yolk sac of the mouse were examined. Maternal vitamin D status did not affect the time of appearance of CaBP-D9k (9 kDa) in the yolk sac endoderm or trophoblastic giant cells (TGCs) of the placenta. VDRs were undetectable in TGCs and yolk sac endoderm, but were present in the intraplacental yolk sac. Since yolk sac endoderm and TGCs contain CaBP but not VDR, it is unlikely that CaBP synthesis and/or activity in these cells is controlled by vitamin D. The TGCs, therefore, may be involved in vitamin D-independent transplacental transfer of calcium.
Journal of Endocrinology (1996) 150, 25–32
Recombinant FSH-induced follicle development in immature rats treated with an LHRH antagonist: a direct effect of RU486 on follicular atresia
Authors: Uilenbroek J Th J , Kramer P , van Leeuwen E C M , Karels B , Timmerman M A , de Jong F H , de Leeuw R 
Published: December 2004

Abstract
To investigate whether the progesterone antagonist RU486 has a direct effect on ovarian function, it was administered to immature female rats rendered hypogonadotrophic by administration of an LHRH antagonist and in which follicle development was stimulated by recombinant human FSH (recFSH).
In the first experiments the effects of LHRH antagonist and recFSH on follicle growth were evaluated. Female rats of 22 days of age were injected with an LHRH antagonist (Org 30276; 500 μg/100 g body weight) every other day. This treatment resulted in a tenfold decrease in serum LH concentrations and a twofold decrease in serum FSH concentrations at day 30 and caused a reduction in the number and size of antral follicles. Treatment with recFSH (Org 32489) twice daily from day 26 for 4 days in a total dose ranging from 5 to 20 IU/animal increased the number and size of antral follicles in a dose-related manner and resulted after 20 IU recFSH in a tenfold increase in the concentration of inhibin in serum and ovaries at day 30. Once it was established that LHRH antagonist treatment in immature rats could be used to study the effects of gonadotrophins or steroids on follicle function, this animal model was used to study the effects of RU486 on the ovary. RU486 was administered (twice daily for 4 days, 1 mg/injection) to LHRH antagonist-treated rats in which follicular growth and differentation were stimulated by 10 IU recFSH or by 10 IU recFSH plus 0·5 IU human chorionic gonadotrophin (hCG). RU486 had no effect on circulating levels of LH and FSH, but stimulated follicular atresia both in rats treated with recFSH alone and in rats treated with recFSH and hCG. Inhibin concentrations both in serum and ovaries were significantly increased after hCG treatment. RU486, however, did not increase inhibin in the rats treated with recFSH and in those treated with recFSH and hCG.
In summary, the present study has demonstrated that (1) immature rats treated with an LHRH antagonist can be used to study the effects of gonadotrophins and steroids on follicular function and (2) RU486 has a direct stimulatory effect on follicular atresia.
Journal of Endocrinology (1996) 150, 85–92
A study of the luteolytic mechanism of the antiprogesterone RU486 during the late-luteal phase in pseudopregnant rats
Authors: Nakamura Y , Tamura H , Ono M , Shimamura K , Sugino N , Numa F , Ueda K , Kato H 
Published: December 2004

Abstract
The purpose of this study was to examine the possible mechanism through which RU486 induces luteolysis during the late-luteal phase in pseudopregnant (PSP) rats. PSP rats received a subcutaneous injection of RU486 in sesame oil (5 mg/kg body weight) or sesame oil alone once a day between day 9 and day 11 of pseudopregnancy. Serial blood samples were collected on days 5, 9, 10, 11 and 12 and assayed for progesterone content. To examine the possible action of RU486 through a uterine and/or a pituitary (prolactin-dependent) mechanism, PSP rats and chronic hysterectomized PSP rats which had been hysterectomized before PSP induction received a subcutaneous injection of RU486 in sesame oil (5 mg/kg body weight), sesame oil alone, prolactin in 50% polyvinylpyrrolidone (15 IU/day), or RU486 and prolactin once a day between day 9 and day 11 of pseudopregnancy. Serial blood samples were collected on days 5, 9, 10 and 11 and assayed for progesterone content. Blood samples were also collected at 0400 h on day 12 and used for prolactin and progesterone determinations. To examine the direct effect of RU486 on corpus luteum and/or pituitary, hysterectomized rats underwent hypophysectomy and pituitary autotransplantation on dioestrus 1 and received a subcutaneous injection of RU486 in sesame oil or sesame oil alone for 3 days between day 21 and day 23 after surgery. Serial blood samples were collected on days 10, 21, 22, 23 and 24 and assayed for progesterone and prolactin contents.
In ordinary PSP rats, serum progesterone levels were significantly (P<0·01) lower in the RU486-treated group than in the control group (9 ± 1 vs 53 ± 7 ng/ml; mean ± s.e.m.) on day 11. Serum prolactin levels at 0400 h on day 12 of pseudopregnancy were significantly (P<0·05) lower in the RU486-treated group than in the control group (16 ±4 vs 154 ±44 ng/ml; mean ± s.e.m.). The concomitant prolactin treatment reversed the luteolytic effects of RU486 on day 11 of pseudopregnancy. In hysterectomized PSP rats, RU486 also suppressed serum prolactin levels, and the concomitant prolactin treatment again reversed the luteolytic effects of RU486. In hysterectomized rats which were hypophysectomized and pituitary autotransplanted, RU486 treatment did not induce any significant changes in serum progesterone and prolactin levels.
These results indicated that RU486 induced luteolysis during the late-luteal phase in PSP rats by suppressing prolactin secretion via a hypothalamic mechanism.
Journal of Endocrinology (1996) 150, 93–98
GH inhibition of lipogenesis and stimulation of lipolysis in sheep adipose tissue: involvement of protein serine phosphorylation and dephosphorylation and phospholipase C
Authors: Vernon R G 
Published: December 2004

Abstract
The intracellular signalling systems involved in the chronic insulin-antagonistic, anti-lipogenic effects and also the lipolytic effect of GH have been investigated in sheep adipose tissue in an in vitro tissue culture system. During culture, chronic exposure to GH decreased the rate of lipogenesis and prevented the increase in lipogenesis induced by insulin. GH also increased glycerol release into the culture medium. GH had no acute, insulin-like effect on lipogenesis in sheep adipose tissue.
Pretreatment with phorbol ester to down-regulate isoforms of protein kinase C or addition of the protein serine kinase inhibitor staurosporine decreased the anti-lipogenic effect of GH while the protein serine kinase inhibitor H7 eliminated it completely. Pretreatment with phorbol ester or addition of H7 also decreased the insulin-antagonistic effect of GH on lipogenesis. Addition of the protein serine phosphatase inhibitor okadaic acid or the phosphatidyl choline phospholipase C inhibitor D609 both diminished the anti-lipogenic and insulin-antagonistic effects of GH.
Chronic exposure of adipose tissue to GH had no effect on the total activity of acetyl CoA carboxylase or its activation status but it did diminish the increase in activation status induced by insulin. H7 and okadaic acid also diminished the increase in activation status of acetyl CoA carboxylase induced by insulin but did not alter the effect of GH on this variable. Okadaic acid decreased total acetyl CoA carboxylase activity.
Pretreatment with phorbol ester or the addition of H7, staurosporine or okadaic acid increased glycerol release into the culture medium to the same extent as GH itself; the effects of GH and these various agents were not additive.
These studies suggest that the anti-lipogenic, insulin-antagonistic effects of GH involve both protein serine kinases and phosphatases, possibly including one or more isoforms of protein kinase C, and a phosphatidyl choline-specific phospholipase C. Comparison with studies by others on the GH enhancement of preadipocyte differentiation and prolactin stimulation of lipogenesis in mammary tissue suggests involvement of protein kinase C at an early stage in all three systems. In contrast, effects of okadaic acid vary with the system, suggesting the involvement of protein serine phosphatase activity in a late stage of the action of GH. The effects of GH on lipogenesis and lipolysis do not occur via identical mechanisms.
Journal of Endocrinology (1996) 150, 129–140
Regulation of insulin-like growth factor-binding protein-4 protease activity by estrogen and parathyroid hormone in SaOS-2 cells: implications for the pathogenesis of postmenopausal osteoporosis
Authors: Kudo Y , Iwashita M , Itatsu S , Iguchi T , Takeda Y 
Published: December 2004

Abstract
The cellular mechanisms involved in the accelerated bone loss occurring in association with estrogen deprivation as seen following the menopause are not fully understood. Insulin-like growth factor-I (IGF-I) is the local regulator of osteoblasts and one of its binding proteins, insulin-like growth factor-binding protein-4 (IGFBP-4), binds to IGF-I and suppresses biological activity. Previous studies have shown that the binding activity of IGFBP-4 in the conditioned medium of parathyroid hormone (PTH)-treated SaOS-2 osteoblastic-like cells is enhanced twofold and that this PTH-enhanced IGFBP-4 binding activity is abolished by 17β-estradiol. Levels of IGFBP-4 in the conditioned medium have been reported to be regulated not only at the level of production but also at the level of degradation which is catalyzed by a protease that specifically cleaves IGFBP-4. We have, therefore, studied the effects of 17β-estradiol and PTH on IGFBP-4 protease activity using SaOS-2 cells. SaOS-2 cells produce a protease that specifically cleaves IGFBP-4 into two fragments of approximately 18 and 14 kilodaltons. IGFBP-4 protease activity in the conditioned medium from PTH-treated cells was suppressed, while this PTH-induced suppression of protease activity was reversed by the addition of 17β-estradiol to the cultures. IGFBP-4 proteolytic activity was stimulated by IGF-I or IGF-II added exogenously and was inhibited by EDTA or protease inhibitors. IGFBP-4 proteolyzed in the conditioned medium from cells treated with PTH and 17β-estradiol was less effective at inhibiting IGF-I-stimulated [3H]thymidine incorporation into DNA compared with that proteolyzed in the conditioned medium from PTH-treated cells. The simplest explanation is that 17β-estradiol suppressed the inhibitory effect of PTH on osteoblastic activity by inhibiting the PTH-induced suppression of IGFBP-4 protease activity.
Journal of Endocrinology (1996) 150, 223–229
Pituitary and ovarian expression of the endogenous follicle-stimulating hormone (FSH) subunit genes and an FSH β-subunit promoter-driven herpes simplex virus thymidine kinase gene in transgenic mice; specific partial ablation of FSH-producing cells by antiherpes treatment
Authors: Markkula M , Kananen K , Klemi P , Huhtaniemi I 
Published: December 2004

Abstract
The ovarian expression of the endogenous follicle-stimulating hormone β-subunit (FSHβ) and common α-subunit (Cα) genes, and a herpes simplex virus thymidine kinase (tk) transgene, driven by a 2·3 kb bovine FSHβ promoter, was studied in normal and transgenic (tg) mice. tk functions not only as a neutral reporter that enables the study of the promoter function but also as an exogenously inducible toxigene. Reverse transcriptionPCR followed by Southern blot hybridization with a nested probe was used to show the expression of the gene at the mRNA level. Common α-subunit mRNA was detected in the pituitary gland and ovaries of normal adult mice. We have previously detected endogenous FSHβ and tg tk mRNAs in the mouse pituitary, testis and ovary. In this study, the cellular localization of the corresponding proteins was visualized by immunocytochemistry. In normal mouse ovaries a positive reaction with FSHβ and Cα antisera was seen in some of the corpora lutea and most prominently in the interstitial cells. A positive reaction with the tk antiserum was seen in the same cell types of tg mouse ovaries, but not in those of non-tg mice. Cell-ablation-inducing treatment (gancyclovir, 20 mg/kg per day, for 14 days) of tg female mice reduced pituitary FSH concentrations by 52% (P<0·05) but did not affect pituitary LH or plasma gonadotropins compared with non-tg females treated in the same way. A longer period of cell ablation induction (acyclovir 400 mg/kg per day, for 21 days) reduced not only pituitary but also plasma FSH concentrations (55 and 57% respectively; P<0·05) without affecting LH. This treatment also reduced ovarian weight by 38% (P<0·01). In conclusion, our results show first that the endogenous FSHβ and Cα proteins are produced in the mouse ovary. Hence, endogenously synthesized FSH or its subunits may have a role in the paracrine regulation of ovarian function. Secondly, the FSHβ promoter directs the expression of tg tk in the pituitary gonadotrope cells, as shown by specific but partial ablation of FSH-producing cells after induction by gancyclovir and acyclovir. In the ovary, tk protein was localized to the same compartments as the endogenous gonadotropin subunit proteins. This further confirms our finding of ovarian expression of the FSH subunit genes.
Journal of Endocrinology (1996) 150, 265–273
Activation of protein kinase A and protein kinase C mediates the depolarising effect of LH in ovine cumulus-corona cells
Authors: Mattioli M , Barboni B , Gioia L 
Published: December 2004

Abstract
We have studied the changes in membrane potential induced by LH in cumulus and granulosa cells isolated from sheep antral follicles. The investigation was carried out by using a non-invasive technique based on the use of a membrane potential sensitive probe, bis-oxonol. The membrane potential of mural granulosa cells was totally unaffected by LH, while that of cumulus or corona cells showed a marked depolarisation, starting 2–3 min after the addition of the hormone and plateauing after 5–10 min. None of the cells tested reacted to FSH.
In the second part of the experiment the role of protein kinase A (PKA) and protein kinase C (PKC) in mediating the effect of LH was studied. The selective activation of PKA or PKC induced in cumulus-corona cells a rapid hyperpolarisation due to increased Cl and K conductance respectively. By contrast, the simultaneous activation of the two kinases induced a rapid membrane depolarisation due to the progressive decrease in K conductance. The activation of each kinase or their combined stimulation did not induce any change in the membrane potential of mural granulosa cells. These data demonstrated that LH has a depolarising effect regionally circumscribed to cumulus-corona cells and that this depolarisation depends on a reduction of K conductance caused by the activation of PKA and PKC.
Journal of Endocrinology (1996) 150, 445–456
Labour-associated increase in interleukin-1 α release in vitro by human gestational tissues
Authors: Laham N , Brennecke S P , Bendtzen K , Rice G E 
Published: December 2004

Abstract
The aims of this study were to investigate the concentration and release of interleukin-1α (IL-1α) at the time of human term labour, and to study the regulation of IL-1α release from human gestational tissue explants by bacterial endotoxin. Immunoreactive IL-1α concentrations in maternal plasma, amniotic fluid and conditioned media from human amniotic, choriodecidual and placental explants were quantified before and after spontaneous term labour-onset and delivery. Furthermore, the effects of a bacterial endotoxin, lipopolysaccharide (LPS), on the release of IL-1α from human gestational tissue explants over a time course of 24 h (n=3) and LPS concentrations ranging from 10–107 pg/ml (n=3) were investigated. IL-1α concentrations in maternal plasma and amniotic fluid did not change significantly with spontaneous term labour-onset. In contrast, IL-1α was released in detectable amounts from human amniotic and choriodecidual explants only in association with term labour-onset and delivery. Similarly, placental release of IL-1α was increased significantly in explant cultures in association with term labour-onset and delivery. LPS increased IL-1α release significantly only from human placental explants from both term not-in-labour and term after-labour tissues. The data demonstrate differential regulation of IL-1α release from human gestational tissues in association with labour and LPS treatment and the observations support the hypothesis that the labour-associated increase in IL-1α release from the fetal membranes is independent of exposure to bacterial endotoxin.
Journal of Endocrinology (1996) 150, 515–522