scholarly journals Peptide YY (PYY)3–36 modulates thyrotropin secretion in rats

2006 ◽  
Vol 191 (2) ◽  
pp. 459-463 ◽  
Author(s):  
K J Oliveira ◽  
G S M Paula ◽  
R H Costa-e-Sousa ◽  
L L Souza ◽  
D C Moraes ◽  
...  
Keyword(s):  
Peptide Yy ◽  
Significant Rise ◽  
Gonadotropin Secretion ◽  
Gut Hormone ◽  
Pituitary Glands ◽  
Thyroid Axis ◽  
Dose Dependent Decrease ◽  
Serum Tsh

Peptide YY (PYY)3-36 is a gut-derived hormone, with a proposed role in central mediation of postprandial satiety signals, as well as in long-term energy balance. In addition, recently, the ability of the hormone to regulate gonadotropin secretion, acting at pituitary and at hypothalamus has been reported. Here, we examined PYY3-36 effects on thyrotropin (TSH) secretion, both in vitro and in vivo. PYY3-36-incubated rat pituitary glands showed a dose-dependent decrease in TSH release, with 44 and 62% reduction at 10−8 and 10−6 M (P < 0.05 and P < 0.001 respectively), and no alteration in TSH response to thyrotropin-releasing hormone. In vivo, PYY3-36 i.p. single injection in the doses of 3 or 30 cg/kg body weight, administered to rats fed ad libitum, was not able to change serum TSH after 15 or 30 min. However, in fasted rats, PYY3-36 at both doses elicited a significant rise (approximately twofold increase, P < 0.05) in serum TSH observed 15 min after the hormone injection. PYY3-36 treatment did not modify significantly serum T4, T3, or leptin. Therefore, in the present paper, we have demonstrated that the gut hormone PYY3-36 acts directly on the pituitary gland to inhibit TSH release, and in the fasting situation, in vivo, when serum PYY3-36 is reduced, the activity of thyroid axis is reduced as well. In such a situation, systemically injected PYY3-36 was able to acutely activate the thyrotrope axis, suggesting a new role for PYY3-36 as a regulator of the hypothalamic–pituitary–thyroid axis.

Anti-thrombotic Effect of a PAI-1 Inhibitor in Rats Given Endotoxin

1996 ◽  
Vol 75 (01) ◽  
pp. 118-126 ◽  
Author(s):  
T Abrahamsson ◽  
V Nerme ◽  
M Strömqvist ◽  
B Åkerblom ◽  
A Legnehed ◽  
...  
Keyword(s):  
Plasminogen Activator Inhibitor ◽  
Rat Plasma ◽  
Clot Lysis ◽  
Fibrin Deposition ◽  
Plasminogen Activator Inhibitor 1 ◽  
Fab Fragment ◽  
Dose Dependent Decrease ◽  
Pai 1

SummaryThe aim of this study was to investigate the anti-thrombotic effects of an inhibitor of the plasminogen activator inhibitor-1 (PAI-1) in rats given endotoxin. In studies in vitro, PRAP-1, a Fab-fragment of a polyclonal antibody against human PAI-1, was shown to inhibit PAI-1 activity in rat plasma as well as to stimulate clot-lysis of the euglobulin fraction derived from rat plasma. Endotoxin administered to anaesthetised rats produced a marked increase in plasma PAI-1 activity. To study fibrin formation and lysis in vivo after intravenous (i. v.) injection of the coagulant enzyme batroxobin, 125I-fibrinogen was administered to the animals. The thrombi formed by batroxobin were rapidly lysed in control animals, while the rate of lysis was markedly attenuated in rats given endotoxin. PRAP-1 was administered i.v. (bolus + infusion) to rats given endotoxin and batroxobin and the PAI-1 inhibitor caused a dose-dependent decrease in the 125I-fibrin deposition in the lungs. An immunohistochemical technique was used to confirm this decrease in density of fibrin clots in the tissue. Furthermore, PRAP-1 decreased plasma PAI-1 activity in the rats and this reduction was correlated to the decrease in lung 125I-fibrin deposition at the corresponding time point. It is concluded that in this experimental model the PAI-1 antibody PRAP-1 may indeed inhibit thrombosis in animals exposed to endotoxin.

scholarly journals 64Cu-ATSM/64Cu-Cl2 and their relationship to hypoxia in glioblastoma: a preclinical study

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Elodie A. Pérès ◽  
Jérôme Toutain ◽  
Louis-Paul Paty ◽  
Didier Divoux ◽  
Méziane Ibazizène ◽  
...  
Keyword(s):  
Ex Vivo ◽  
In Vitro Study ◽  
Tumor Location ◽  
Preclinical Study ◽  
Significant Rise ◽  
Lower Oxygen ◽  
Cu Complexes ◽  
Ex Vivo Study

Abstract Background Diacetyl-bis(N4-methylthiosemicarbazone), labeled with 64Cu (64Cu-ATSM) has been suggested as a promising tracer for imaging hypoxia. However, various controversial studies highlighted potential pitfalls that may disable its use as a selective hypoxic marker. They also highlighted that the results may be tumor location dependent. Here, we first analyzed uptake of Cu-ATSM and its less lipophilic counterpart Cu-Cl2 in the tumor over time in an orthotopic glioblastoma model. An in vitro study was also conducted to investigate the hypoxia-dependent copper uptake in tumor cells. We then further performed a comprehensive ex vivo study to compare 64Cu uptake to hypoxic markers, specific cellular reactions, and also transporter expression. Methods μPET was performed 14 days (18F-FMISO), 15 days (64Cu-ATSM and 64Cu-Cl2), and 16 days (64Cu-ATSM and 64Cu-Cl2) after C6 cell inoculation. Thereafter, the brains were withdrawn for further autoradiography and immunohistochemistry. C6 cells were also grown in hypoxic workstation to analyze cellular uptake of Cu complexes in different oxygen levels. Results In vivo results showed that Cu-ASTM and Cu-Cl2 accumulated in hypoxic areas of the tumors. Cu-ATSM also stained, to a lesser extent, non-hypoxic regions, such as regions of astrogliosis, with high expression of copper transporters and in particular DMT-1 and CTR1, and also characterized by the expression of elevated astrogliosis. In vitro results show that 64Cu-ATSM showed an increase in the uptake only in severe hypoxia at 0.5 and 0.2% of oxygen while for 64Cu-Cl2, the cell retention was significantly increased at 5% and 1% of oxygen with no significant rise at lower oxygen percentages. Conclusion In the present study, we show that Cu-complexes undoubtedly accumulate in hypoxic areas of the tumors. This uptake may be the reflection of a direct dependency to a redox metabolism and also a reflection of hypoxic-induced overexpression of transporters. We also show that Cu-ATSM also stained non-hypoxic regions such as astrogliosis.

scholarly journals Effects of Bacterial CLPB Protein Fragments on Food Intake and PYY Secretion

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2223
Author(s):  
Manon Dominique ◽  
Nicolas Lucas ◽  
Romain Legrand ◽  
Illona-Marie Bouleté ◽  
Christine Bôle-Feysot ◽  
...  
Keyword(s):  
Food Intake ◽  
Peptide Yy ◽  
Molecular Mimicry ◽  
Potential Effect ◽  
In Vivo Studies ◽  
Sprague Dawley ◽  
E Coli ◽  
In Vivo Effects

CLPB (Caseinolytic peptidase B) protein is a conformational mimetic of α-MSH, an anorectic hormone. Previous in vivo studies have already shown the potential effect of CLPB protein on food intake and on the production of peptide YY (PYY) by injection of E. coli wild type (WT) or E. coli ΔClpB. However, until now, no study has shown its direct effect on food intake. Furthermore, this protein can fragment naturally. Therefore, the aim of this study was (i) to evaluate the in vitro effects of CLPB fragments on PYY production; and (ii) to test the in vivo effects of a CLPB fragment sharing molecular mimicry with α-MSH (CLPB25) compared to natural fragments of the CLPB protein (CLPB96). To do that, a primary culture of intestinal mucosal cells from male Sprague–Dawley rats was incubated with proteins extracted from E. coli WT and ΔCLPB after fragmentation with trypsin or after a heat treatment of the CLPB protein. PYY secretion was measured by ELISA. CLPB fragments were analyzed by Western Blot using anti-α-MSH antibodies. In vivo effects of the CLPB protein on food intake were evaluated by intraperitoneal injections in male C57Bl/6 and ob/ob mice using the BioDAQ® system. The natural CLPB96 fragmentation increased PYY production in vitro and significantly decreased cumulative food intake from 2 h in C57Bl/6 and ob/ob mice on the contrary to CLPB25. Therefore, the anorexigenic effect of CLPB is likely the consequence of enhanced PYY secretion.

A Detailed Examination of the in vivo and in vitro Effects of ACTH on Gonadotropin Secretion in the Adult Rat

1985 ◽  
Vol 40 (4) ◽  
pp. 297-302 ◽  
Author(s):  
David R. Mann ◽  
Diane Evans ◽  
Festus Edoimioya ◽  
Freja Kamel ◽  
George M. Butterstein
Keyword(s):  
Detailed Examination ◽  
Gonadotropin Secretion ◽  
Adult Rat ◽  
In Vitro Effects

Effect of Estrogen on Melanocortin-3 Receptor mRNA Expression in Mouse Pituitary Glands in vivo and in vitro

2004 ◽  
Vol 80 (3) ◽  
pp. 143-151 ◽  
Author(s):  
Ryusei Matsumura ◽  
Sakae Takeuchi ◽  
Sumio Takahashi
Keyword(s):  
Mrna Expression ◽  
Receptor Mrna ◽  
Pituitary Glands ◽  
Mouse Pituitary

In-vivo and in-vitro secretion of prolactin by lactating rat adenohypophyses as a function of intracellular age

1984 ◽  
Vol 101 (1) ◽  
pp. 27-32 ◽  
Author(s):  
F. Mena ◽  
G. Martínez-Escalera ◽  
C. Clapp ◽  
C. E. Grosvenor
Keyword(s):  
Pituitary Gland ◽  
Incubation Period ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Pituitary Glands ◽  
H 26

ABSTRACT Adenohypophysial prolactin of lactating rats was pulse-labelled by [3H]leucine injected i.v. at the time of removal of the pups. The [3H]prolactin concentration in the pituitary gland, analysed by polyacrylamide-gel electrophoresis, progressively fell as the time from labelling to removal of the pituitary gland increased from 8 to 24 h, which suggests that there was a loss of hormone as it aged within the gland. Suckling effectively provoked the depletion–transformation of total and [3H]prolactin (extracted at pH 7·2) when applied after 8 h but not when applied after either 16 or 24 h after removing the pups. In rats whose pups were removed for 8 h, suckling also depleted–transformed [3H]prolactin labelled 4 h, but not that labelled 1 h before suckling. The pituitary glands of other lactating rats were labelled with [3H]leucine injected i.v. at various times before removing the glands and incubating them in medium 199. The secretion into the medium of [3H]prolactin labelled either 4, 8, 16 or 24 h beforehand was maximal during the first 30 min then declined from 30 to 240 min of incubation. However, secretion of prolactin labelled 1 h and 10 min beforehand reached a maximum after 0·5–1 h and 2 h of incubation respectively, then remained constant during the remainder of the 4-h incubation period. The total 4-h secretion of [3H]prolactin was greatest (65% of preincubation concentration) from those glands labelled 4 h before in contrast to those labelled 10 min (15%) or 1 (38%), 8 (34%), 16 (18%) or 24 h (26%) before incubation. Taken together, these data suggest that prolactin synthesized 4 h earlier is more likely to be released in response to physiological stimuli than is more recently formed prolactin or prolactin which has remained in the pituitary gland for 16 h or longer. J. Endocr. (1984) 101, 27–32

scholarly journals Derivation of macaque trophoblast stem cells

2020 ◽  
Author(s):  
Jenna Kropp Schmidt ◽  
Michael G. Meyer ◽  
Gregory J. Wiepz ◽  
Lindsey N. Block ◽  
Brittany M. Dusek ◽  
...  
Keyword(s):  
Stem Cells ◽  
Culture Media ◽  
Syncytium Formation ◽  
First Trimester ◽  
Gonadotropin Secretion ◽  
Trophoblast Stem Cells ◽  
Trophoblast Stem ◽  
Mhc Class I Molecule

AbstractNonhuman primates are excellent models for studying human placentation as experimental manipulations in vitro can be translated to in vivo pregnancy. Our objective was to develop macaque trophoblast stem cells (TSC) as an in vitro platform for future assessment of primate trophoblast development and function. Macaque TSC lines were generated by isolating first trimester placental villous cytotrophoblasts followed by culture in TSC medium to “reprogram” the cells to a proliferative state. TSCs grew as mononuclear colonies, whereas upon induction of syncytiotrophoblast (ST) differentiation multinuclear structures appeared, indicative of syncytium formation. Chorionic gonadotropin secretion was >4,000-fold higher in ST culture media compared to TSC media. Characteristic trophoblast hallmarks were defined in TSCs and ST including expression of C19MC miRNAs and macaque placental nonclassical MHC class I molecule, Mamu-AG. TSC differentiation to extravillous trophoblasts (EVTs) with or without the ALK-5 inhibitor A83-01 resulted in differing morphologies but similar expression of Mamu-AG and CD56 as assessed by flow cytometry, hence further refinement of relevant EVT markers is needed. Our preliminary characterization of macaque TSCs suggests that these cells represent a proliferative, self-renewing TSC population capable of differentiating to STs in vitro thereby establishing an experimental model of primate placentation.

scholarly journals DEVELOPMENT OF RITONAVIR LOADED NANOPARTICLES: IN VITRO AND IN VIVO CHARACTERIZATION

2018 ◽  
Vol 11 (3) ◽  
pp. 284
Author(s):  
Pravin S Patil ◽  
Shashikant C Dhawale
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Dissolution Rate ◽  
Drug Carrier ◽  
Entrapment Efficiency ◽  
Significant Rise ◽  
Scanning Calorimetry ◽  
In Vitro Drug Release

 Objective: The purpose of the present investigation was to develop a nanosuspension to improve dissolution rate and oral bioavailability of ritonavir.Methods: Extended-release ritonavir loaded nanoparticles were prepared using the polymeric system by nanoprecipitation technique. Further, the effect of Eudragit RL100 (polymeric matrix) and polyvinyl alcohol (surfactant) was investigated on particle size and distribution, drug content, entrapment efficiency, and in vitro drug release from nanosuspension where a strong influence of polymeric contents was observed. Drug-excipient compatibility and amorphous nature of drug in prepared nanoparticles were confirmed by Fourier transform infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffraction studies, respectively.Results: Hydrophobic portions of Eudragit RL100 could result in enhanced encapsulation efficiency. However, increase in polymer and surfactant contents lead to enlarged particle size proportionately as confirmed by transmission electron microscopy. Nanosuspension showed a significant rise in dissolution rate with complete in vitro drug release as well as higher bioavailability in rats compared to the pure drug.Conclusion: The nanoprecipitation technique used in present research could be further explored for the development of different antiretroviral drug carrier therapeutics.

scholarly journals Microfluidics in male reproduction: is ex vivo culture of primate testis tissue a future strategy for ART or toxicology research?

2020 ◽  
Vol 26 (3) ◽  
pp. 179-192 ◽  
Author(s):  
Swati Sharma ◽  
Bastien Venzac ◽  
Thomas Burgers ◽  
Séverine Le Gac ◽  
Stefan Schlatt
Keyword(s):  
Male Infertility ◽  
Functional Organization ◽  
Ex Vivo ◽  
Significant Rise ◽  
Male Reproduction ◽  
Potential Applications ◽  
On Chip ◽  
Bio Engineering

Abstract The significant rise in male infertility disorders over the years has led to extensive research efforts to recapitulate the process of male gametogenesis in vitro and to identify essential mechanisms involved in spermatogenesis, notably for clinical applications. A promising technology to bridge this research gap is organ-on-chip (OoC) technology, which has gradually transformed the research landscape in ART and offers new opportunities to develop advanced in vitro culture systems. With exquisite control on a cell or tissue microenvironment, customized organ-specific structures can be fabricated in in vitro OoC platforms, which can also simulate the effect of in vivo vascularization. Dynamic cultures using microfluidic devices enable us to create stimulatory effect and non-stimulatory culture conditions. Noteworthy is that recent studies demonstrated the potential of continuous perfusion in OoC systems using ex vivo mouse testis tissues. Here we review the existing literature and potential applications of such OoC systems for male reproduction in combination with novel bio-engineering and analytical tools. We first introduce OoC technology and highlight the opportunities offered in reproductive biology in general. In the subsequent section, we discuss the complex structural and functional organization of the testis and the role of the vasculature-associated testicular niche and fluid dynamics in modulating testis function. Next, we review significant technological breakthroughs in achieving in vitro spermatogenesis in various species and discuss the evidence from microfluidics-based testes culture studies in mouse. Lastly, we discuss a roadmap for the potential applications of the proposed testis-on-chip culture system in the field of primate male infertility, ART and reproductive toxicology.

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