scholarly journals Stress hormone masculinizes female morphology and behaviour

2010 ◽  
Vol 7 (1) ◽  
pp. 150-152 ◽  
Author(s):  
Rosemary Knapp ◽  
Edie Marsh-Matthews ◽  
Luanne Vo ◽  
Sarah Rosencrans
Keyword(s):  
Sexual Differentiation ◽  
Sex Steroids ◽  
Full Range ◽  
Reproductive Function ◽  
Morphological Characters ◽  
Sexually Dimorphic ◽  
Dependent Manner ◽  
Stress Hormone ◽  
Naturally Occurring ◽  
Dose Dependent

Sex steroids play major roles in vertebrate sexual differentiation. Unexpectedly, we now find that exposure to elevated levels of the naturally occurring stress hormone cortisol can also masculinize sexually dimorphic morphological characters and behaviour in adult female mosquitofish ( Gambusia affinis ) in a dose-dependent manner. Females masculinized by cortisol developed elongated anal fins with distal tip features similar to those of mature males. Most masculinized females also attempted to copulate when placed with normal females. Although the mechanism of masculinization is currently unknown, we propose a role for an enzyme that both inactivates cortisol and catalyzes the final step in synthesis of a major teleost androgen. This mechanism may also help explain some previously reported effects of stress on sexual development across vertebrate taxa. Our findings underscore the need to understand the full range of chemicals, both naturally occurring hormones and human-produced endocrine disruptors, that can influence sexual differentiation and reproductive function.

scholarly journals Acetylcholinesterase and Butyrylcholinesterase Inhibitory Compounds from Chelidonium Majus (Papaveraceae)

2010 ◽  
Vol 5 (11) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Lucie Cahlíková ◽  
Lubomír Opletal ◽  
Milan Kurfürst ◽  
Kateřina Macáková ◽  
Andrea Kulhánková ◽  
...  
Keyword(s):  
Human Plasma ◽  
Human Blood ◽  
Inhibitory Activity ◽  
Dependent Manner ◽  
Isoquinoline Alkaloids ◽  
Chelidonium Majus ◽  
Aerial Parts ◽  
Naturally Occurring ◽  
Inhibitory Compounds ◽  
Dose Dependent

The roots and aerial parts of Chelidonium majus L. were extracted with EtOH and fractionated using CHCl3 and EtOH. Repeated column chromatography, preparative TLC and crystallization led to the isolation of five isoquinoline alkaloids, stylopine (3), chelidonine (4), homochelidonine (5), protopine (6), and allocryptopine (7), along with two isolation artifacts 6-ethoxydihydrosanguinarine (1) and 6-ethoxydihydrochelerythrine (2). All isolated compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. The isolation artifacts exhibited the highest activity against HuAChE and HuBuChE with IC50 values of 0.83 ± 0.04 μM and 4.20 ± 0.19 μM for 6-ethoxydihydrochelerythrine and 3.25 ± 0.24 μM and 4.51 ± 0.31 μM for 6-ethoxydihydrosanguinarine. The most active of the naturally-occurring alkaloids was chelidonine, which inhibited both HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 26.8 ± 1.2 μM and 31.9 ± 1.4 μM, respectively.

scholarly journals Opposing Roles of Leptin and Ghrelin in the Equine Corpus Luteum Regulation: AnIn VitroStudy

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
António Galvão ◽  
Angela Tramontano ◽  
Maria Rosa Rebordão ◽  
Ana Amaral ◽  
Pedro Pinto Bravo ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Reproductive Function ◽  
Secretory Activity ◽  
Dependent Manner ◽  
Angiogenic Activity ◽  
Metabolic Hormones ◽  
Protein Levels ◽  
Dose Dependent

Metabolic hormones have been associated with reproductive function modulation. Thus, the aim of this study was: (i) to characterize the immunolocalization, mRNA and protein levels of leptin (LEP), Ghrelin (GHR) and respective receptors LEPR and Ghr-R1A, throughout luteal phase; and (ii) to evaluate the role of LEP and GHR on progesterone (P4), prostaglandin (PG) E2and PGF2α, nitric oxide (nitrite), tumor necrosis factor-α(TNF); macrophage migration inhibitory factor (MIF) secretion, and on angiogenic activity (BAEC proliferation), in equine corpus luteum (CL) from early and mid-luteal stages. LEPR expression was decreased in late CL, while GHR/Ghr-R1A system was increased in the same stage. Regarding secretory activity, GHR decreased P4in early CL, but increased PGF2α, nitrite and TNF in mid CL. Conversely, LEP increased P4, PGE2, angiogenic activity, MIF, TNF and nitrite during early CL, in a dose-dependent manner. Thein vitroeffect of LEP on secretory activity was reverted by GHR, when both factors acted together. The present results evidence the presence of LEP and GHR systems in the equine CL. Moreover, we suggest that LEP and GHR play opposing roles in equine CL regulation, with LEP supporting luteal establishment and GHR promoting luteal regression. Finally, a dose-dependent luteotrophic effect of LEP was demonstrated.

The effect of sex steroids on the degradation of LRH by hypothalamic homogenates

1981 ◽  
Vol 98 (3) ◽  
pp. 321-325 ◽  
Author(s):  
Anna C. Tate ◽  
A. D. Swift
Keyword(s):  
Negative Feedback ◽  
Sex Steroids ◽  
Peptidase Activity ◽  
Dependent Manner ◽  
The Mean ◽  
Dose Dependent Increase ◽  
Dose Dependent

Abstract. Extract of hypothalami was prepared which contained peptidase capable of degrading LRH. The degradation of LRH by this extract either alone or under the influence of oestrogens, androgens and cholesterol, when added to the extract was measured. Oestrone, oestradiol and oestriol (1 pg to 100 pg) stimulated mean peptidase activity significantly (P< 0.001) in a dose-dependent manner. Testosterone (0.1 ng to 10 ng) also caused a dose-dependent increase in degradation of LRH, the two highest doses used significantly increasing the mean activity (P < 0.001). Only the highest dose of androstenedione (10 ng) or dehydroepiandrosterone (10 ng) caused a significant increase of the mean LRH degradation (P < 0.05). Neither cholesterol nor dihydrotestosterone increased peptidase activity when added to the extract. It is suggested that it is possible that these peptidase enzymes could occupy a role in the negative feedback of steroids on the hypothalamus.

scholarly journals Naturally occurring human anti-band 3 autoantibodies accelerate clearance of erythrocytes in guinea pigs

Blood ◽  
1995 ◽  
Vol 85 (7) ◽  
pp. 1920-1928 ◽  
Author(s):  
U Giger ◽  
B Sticher ◽  
R Naef ◽  
R Burger ◽  
HU Lutz
Keyword(s):  
Guinea Pigs ◽  
Band 3 ◽  
Complement C3 ◽  
Erythrocyte Membranes ◽  
Dependent Manner ◽  
Band 3 Protein ◽  
Naturally Occurring ◽  
Dose Dependent

A variety of naturally occurring autoantibodies (NOAs) have been found in sera of animals and humans. Although their specific homeostatic role in the clearance of altered or senescent cells has been proposed and in vitro studies support such functions, in vivo evidence has been lacking. We studied the effect of affinity-purified human anti-band 3 NOA on the survival of untreated and diamide-treated erythrocytes in normal and complement C3-deficient guinea pigs. In vitro exposure to diamide, an oxidative agent, severely reduced the erythrocyte deformability and increased the amount of high-molecular-weight forms of band 3 protein and band 3-hemoglobin adducts in erythrocyte membranes, thereby markedly shortening the survival of these cells in vivo. Human anti-band 3 NOA bound in a dose-dependent manner to erythrocytes, and binding increased with exposure to diamide. In normal guinea pigs anti-band 3 NOA significantly accelerated the clearance of erythrocytes that were mildly damaged by iodine surface labeling and of those that were further oxidized by diamide. However, the anti-band 3 effect was transient and small. In contrast, anti-band 3 NOA did not significantly alter erythrocyte survival in functionally C3-deficient guinea pigs, thereby supporting the C3b requirement for anti-band 3 NOA activity. On the other hand, a pretreatment of animals with purified human band 3 protein slowed down the clearance of erythrocytes incubated with IgG depleted of anti-band 3 NOA. These results provide the first in vivo evidence of a role for anti-band 3 NOA in the clearance of erythrocytes.

scholarly journals Lysophosphatidic Acid Stimulates MCP-1 Secretion from C2C12 Myoblast

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Tamotsu Tsukahara ◽  
Hisao Haniu
Keyword(s):  
Lysophosphatidic Acid ◽  
Cell Types ◽  
C2c12 Cells ◽  
C2c12 Myoblast ◽  
Dependent Manner ◽  
Naturally Occurring ◽  
Chemotactic Protein ◽  
Cyclic Phosphatidic Acid ◽  
Cell Migration And Proliferation ◽  
Dose Dependent

Chemokines are regulatory proteins that play an important role in muscle cell migration and proliferation. In this study, C2C12 cells treated with lysophosphatidic acid (LPA) showed an increase in endogenous monocyte chemotactic protein-1 (MCP-1) expression and secretion. LPA is a naturally occurring bioactive lysophospholipid with hormone- and growth-factor-like activities. LPA is produced by activated platelets, cytokine-stimulated leukocytes, and possibly by other cell types. However, the LPA analog cyclic phosphatidic acid (cPA) had no effect on the expression and secretion of MCP-1. LPA, although similar in structure to cPA, had potent inducing effects on MCP-1 expression in C2C12 cells. In this study, we showed that LPA enhanced MCP-1 mRNA expression and protein secretion in a dose-dependent manner. Taken together, these results suggest that LPA enhances MCP-1 secretion in C2C12 cells and thus may play an important role in cell proliferation.

Evaluation of Dose and Route Effects of Platelet Activating Factor-Induced Extravasation in the Guinea Pig

1984 ◽  
Vol 52 (01) ◽  
pp. 034-036 ◽  
Author(s):  
Dean A Handley ◽  
Ronald G Van Valen ◽  
Mary Kay Melden ◽  
Robert N Saunders
Keyword(s):  
Guinea Pig ◽  
Platelet Activating Factor ◽  
The Other ◽  
Plasma Extravasation ◽  
Dependent Manner ◽  
Naturally Occurring ◽  
Protein Rich ◽  
Dose Dependent

SummaryPlatelet-activating factor (PAF) is a naturally occurring lipid that is reported to induce vessel hyperpermeability leading to loss of protein-rich plasma (extravasation). We have quantitated the systemic extravasation effects of synthetic PAF in the guinea pig by monitoring increases in hematocrit. When given intravenously (10-170 ng/kg), PAF produced dose-dependent increases in hematocrit, with maximal hemoconcentration developing in 5-7 min. In leukopenic animals the expected hematocrit increase was reduced by 57%. PAF given intra-arterially produced the dose-dependent changes in hematocrit similar to the intravenous effects of PAF. However, PAF given intraperitoneally (10-2500 μg/kg) was 800-1100-fold less effective than the other routes and hemoconcentration continued for 30-45 min until a maximal hematocrit was observed. These results show that PAF may markedly influence extravasation of plasma in a dose and route-dependent manner.

Effects of Naturally Occurring Polyols and Urea on Mitochondrial F0F1ATPase

2000 ◽  
Vol 55 (5-6) ◽  
pp. 392-398 ◽  
Author(s):  
Adriana dos Passos Lemos ◽  
Carlos E. Peres-Sampaio ◽  
Horácio Guimarães-Motta ◽  
Jerson L. Silva ◽  
José R. Meyer-Fernandes
Keyword(s):  
Atpase Activity ◽  
Direct Interaction ◽  
Dependent Manner ◽  
Urea Denaturation ◽  
Naturally Occurring ◽  
Activation Level ◽  
Activation Rate ◽  
Initial Activation ◽  
Natural Inhibitor ◽  
Dose Dependent

We show that urea inhibits the ATPase activity of MgATP submitochondrial particles (MgATP-SMP) with Ki = 0.7 м, probably as a result of direct interaction with the structure of F0F1-ATPase. Counteracting compounds (sorbitol, mannitol or inositol), despite slightly (10-20% ) inhibiting the ATPase activity, also protect the F0F1 ATPase against denaturation by urea. However, this protection was only observed at low urea concentrations (less than 1.5 м ) , and in the presence of three polyols, the Ki for urea shift from 0.7 м to 1.2 м. Urea also increases the initial activation rate of latent MgATP-SMP in a dose-dependent-manner. However, when the particles (0.5 mg/ml) were preincubated in the presence of 1 м , 2 м or 3 м urea, a decrease in the activation level occurred after 1 h, 30 and 10 min, respectively. At high MgATP-SMP concentration (3 mg/ml) a decrease in activation was observed after 2 h, 1 h and 20 min, respectively. These data indicate that the effect of urea on the activation of MgATP-SMP depends on time, urea and protein concentrations. It was also observed that polyols suppress the activation of latent MgATP-SMP in a dose-dependent manner, and protect the particles against urea denaturation during activation. We suppose that a decrease in membrane mobility promoted by interactions of polyols with phospholipids around the F0F1 ATPase may also increase the compactation of protein structure, explaining the inhibition of natural inhibitor protein of ATPase (IF1) release and the activation of the enzyme.

Effect of the Suppressor of Underreplication (SuUR) Gene on Position-Effect Variegation Silencing in Drosophila melanogaster

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1209-1220
Author(s):  
E S Belyaeva ◽  
L V Boldyreva ◽  
E I Volkova ◽  
R A Nanayev ◽  
A A Alekseyenko ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Position Effect ◽  
Polytene Chromosomes ◽  
Morphological Characters ◽  
Position Effect Variegation ◽  
Dependent Manner ◽  
Dose Dependent ◽  
Suur Protein ◽  
Chromosome Regions ◽  
Suur Gene

Abstract It has been previously shown that the SuUR gene encodes a protein located in intercalary and pericentromeric heterochromatin in Drosophila melanogaster polytene chromosomes. The SuUR mutation suppresses the formation of ectopic contacts and DNA underreplication in polytene chromosomes; SuUR+ in extra doses enhances the expression of these characters. This study demonstrates that heterochromatin-dependent PEV silencing is also influenced by SuUR. The SuUR protein localizes to chromosome regions compacted as a result of PEV; the SuUR mutation suppresses DNA underreplication arising in regions of polytene chromosomes undergoing PEV. The SuUR mutation also suppresses variegation of both adult morphological characters and chromatin compaction observed in rearranged chromosomes. In contrast, SuUR+ in extra doses and its overexpression enhance variegation. Thus, SuUR affects PEV silencing in a dose-dependent manner. However, its effect is expressed weaker than that of the strong modifier Su(var)2-5.

scholarly journals Increased B lymphopoiesis in genetically sex steroid-deficient hypogonadal (hpg) mice.

1994 ◽  
Vol 180 (2) ◽  
pp. 717-720 ◽  
Author(s):  
G Smithson ◽  
W G Beamer ◽  
K L Shultz ◽  
S W Christianson ◽  
L D Shultz ◽  
...  
Keyword(s):  
Sex Steroids ◽  
Reproductive Function ◽  
B Lymphopoiesis ◽  
Estrogen Replacement ◽  
Negative Regulators ◽  
Interleukin 7 ◽  
B Lineage ◽  
B Cell Precursors ◽  
Dose Dependent ◽  
Bone Physiology

Interleukin 7 (IL-7) responsive B lineage precursors were greatly expanded in genetically hypogonadal female (HPG/Bm-hpg/hpg) mice that have a secondary deficiency in gonadal steroidogenesis. Estrogen replacement in these mice resulted in a dose-dependent reduction in B cell precursors. More modest increases were documented in genetically normal mice that were surgically castrated. These findings complement other recent observations that B lymphopoiesis selectively declines in pregnant or estrogen-treated animals. Sex steroids have long been known to influence such disparate processes as bone physiology and tumor growth, in addition to their importance for reproductive function. We now show that these hormones are important negative regulators of B lymphopoiesis.

scholarly journals Serotonin-enhanced hyperactivation of hamster sperm

Reproduction ◽  
2011 ◽  
Vol 142 (2) ◽  
pp. 255-266 ◽  
Author(s):  
Masakatsu Fujinoki
Keyword(s):  
Reproductive Function ◽  
Dependent Manner ◽  
Receptor Antagonists ◽  
Receptor Agonists ◽  
Dose Dependent

The effects of serotonin on reproductive function were examined using hamster spermatozoa. When serotonin at concentrations from 1 fmol/l to 1 μmol/l was added to modified Tyrode's albumin lactate pyruvate (mTALP) medium, hyperactivation was significantly enhanced. Agonists and antagonists of 5-hydroxytryptamine hydrochloride (5-HT) receptors (5-HT2 and 5-HT4 receptors) were added to the medium. Both 5-HT2 and 5-HT4 receptor agonists significantly enhanced hyperactivation, although the effect was greater than the former. However, both 5-HT2 and 5-HT4 receptor antagonists significantly suppressed serotonin-enhanced hyperactivation, with the former suppressing stimulation by a lower concentration of serotonin than the latter. These results indicate that serotonin enhances hyperactivation via 5-HT2 and/or 5-HT4 receptors in a dose-dependent manner.

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