Effects of leptin replacement on hypothalamic-pituitary growth hormone axis function and circulating ghrelin levels in ob/ob mice

2007 ◽  
Vol 292 (3) ◽  
pp. E891-E899 ◽  
Author(s):  
Raul M. Luque ◽  
Zhi H. Huang ◽  
Bhumik Shah ◽  
Theodore Mazzone ◽  
Rhonda D. Kineman
Keyword(s):  
Growth Hormone ◽  
Food Intake ◽  
Statistical Significance ◽  
Mrna Levels ◽  
Ghrelin Receptor ◽  
Positive Effects ◽  
In Vivo Effects ◽  
The Impact

Leptin-deficient obese mice ( ob/ob) have decreased circulating growth hormone (GH) and pituitary GH and ghrelin receptor (GHS-R) mRNA levels, whereas hypothalamic GH-releasing hormone (GHRH) and somatostatin (SST) expression do not differ from lean controls. Given the fact that GH is suppressed in diet-induced obesity (a state of hyperleptinemia), it remains to be determined whether the absence of leptin contributes to changes in the GH axis of ob/ob mice. Therefore, to study the impact of leptin replacement on the hypothalamic-pituitary GH axis of ob/ob mice, leptin was infused for 7 days (sc), resulting in circulating leptin levels that were similar to wild-type controls (∼1 ng/ml). Leptin treatment reduced food intake, body weight, and circulating insulin while elevating circulating n-octanoyl ghrelin concentrations. Leptin treatment did not alter hypothalamic GHRH, SST, or GHS-R mRNA levels compared with vehicle-treated controls. However, leptin significantly increased pituitary GH and GHRH-R expression and tended to enhance circulating GH levels, but this latter effect did not reach statistical significance. In vitro, leptin (1 ng/ml, 24 h) did not affect pituitary GH, GHRH-R, or GHS-R mRNA but did enhance GH release. The in vivo effects of leptin on circulating hormone and pituitary mRNA levels were not replicated by pair feeding ob/ob mice to match the food intake of leptin-treated mice. However, leptin did prevent the fall in hypothalamic GHRH mRNA and circulating IGF-I levels observed in pair-fed mice. These results demonstrate that leptin replacement has positive effects on multiple levels of GH axis function in ob/ob mice.

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.

Periodic interactions of GH-releasing factor and somatostatin can augment GH release in vitro

1987 ◽  
Vol 253 (5) ◽  
pp. E508-E514
Author(s):  
J. Weiss ◽  
M. J. Cronin ◽  
M. O. Thorner
Keyword(s):  
Growth Hormone ◽  
Human Growth Hormone ◽  
Human Growth ◽  
Male Rat ◽  
Base Line ◽  
Additive Effects ◽  
Growth Hormone Releasing Factor ◽  
The Impact

Growth hormone (GH) is secreted as pulses in vivo. To understand the signals governing this periodicity, we have established a perifusion-based model of pulsatile GH release. Male rat anterior pituitaries were dispersed and perifused with pulses of human growth hormone-releasing factor-(1--40) (GHRF), with or without a continuous or discontinuous somatostatin tonus. An experiment was composed of a 1-h base-line collection followed by four 3-h cycles; each contained single or paired 10-min infusion(s) of 3 nM GHRF. In testing the impact of somatostatin, the protocol was identical except that 0.3 nM somatostatin was added 30 min into the base-line period and then was either continued throughout the study or withdrawn during the periods of GHRF infusion. GH base lines with somatostatin were lower than vehicle base lines (P less than 0.05). GHRF pulses generated consistent peaks of GH release between 200 and 300 ng. min-1. (10(7) cells)-1, and these peaks were not altered by continuous somatostatin. In contrast, withdrawal of somatostatin during GHRF administration elicited markedly higher GH peaks (P less than 0.05) and more total GH release (P less than 0.05). This response could not be accounted for by the additive effects of GHRF and somatostatin withdrawal.

Additive effects of cortisol and growth hormone on regional and systemic lipolysis in humans

2004 ◽  
Vol 286 (3) ◽  
pp. E488-E494 ◽  
Author(s):  
C. B. Djurhuus ◽  
C. H. Gravholt ◽  
S. Nielsen ◽  
S. B. Pedersen ◽  
N. Møller ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Adipose Tissue ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Additive Effects ◽  
Subcutaneous Adipose ◽  
In Vivo Effects ◽  
Circulating Levels

Growth hormone (GH) and cortisol are important to ensure energy supplies during fasting and stress. In vitro experiments have raised the question whether GH and cortisol mutually potentiate lipolysis. In the present study, combined in vivo effects of GH and cortisol on adipose and muscle tissue were explored. Seven lean males were examined four times over 510 min. Microdialysis catheters were inserted in the vastus lateralis muscle and in the subcutaneous adipose tissue of the thigh and abdomen. A pancreatic-pituitary clamp was maintained with somatostatin infusion and replacement of GH, insulin, and glucagon at baseline levels. At t = 150 min, administration was performed of NaCl (I), a 2 μg·kg-1·min-1hydrocortisone infusion (II), a 200-μg bolus of GH (III), or a combination of II and III (IV). Systemic free fatty acid (FFA) turnover was estimated by [9,10-3H]palmitate appearance. Circulating levels of glucose, insulin, and glucagon were comparable in I-IV. GH levels were similar in I and II (0.50 ± 0.08 μg/l, mean ± SE). Peak levels during III and IV were ∼9 μg/l. Cortisol levels rose to ∼900 nmol/l in II and IV. Systemic (i.e., palmitate fluxes, s-FFA, s-glycerol) and regional (interstitial adipose tissue and skeletal muscle) markers of lipolysis increased in response to both II and III. In IV, they were higher and equal to the isolated additive effects of the two hormones. In conclusion, we find that GH and cortisol stimulate systemic and regional lipolysis independently and in an additive manner when coadministered. On the basis of previous studies, we speculate that the mode of action is mediated though different pathways.

Effect of the ADAPT strategy on dormant CD133+ colon cancer stem cells (CSC) and molecular complete remission measured by peripheral blood mononuclear (PBMC) CD133 mRNA.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e14153-e14153
Author(s):  
Edward H. Lin ◽  
Yu Xiazhen ◽  
Xi C He ◽  
Xifeng Wu ◽  
Yang Xie ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Median Survival ◽  
Treatment Protocol ◽  
Mrna Levels ◽  
Peripheral Blood Mononuclear ◽  
Colon Cells ◽  
Ca Ix ◽  
The Impact

e14153 Background: The median survival for patients with unresectable metastatic colorectal cancer (CRC) is ~2 years with modern chemotherapy which yields only 5-10% complete responses (CR) including metastasectomy. Recurrences after CR are very common thanks to presence of dormant CSC that are best targeted by our proposed two-step ADAPT strategy: activate from dormancy and potentiate targeting. We examine this strategy in various CRC models and reviewed the impact on stemess including CD133 mRNA, a circulating CSC marker that predict colon cancer relapse. Methods: Different CRC models (in vitro and in vivo) were interrogated similar to clinical ADAPT treatment protocol using capecitabine (or 5FU) plus celecoxib. We also conducted IRB approved retrospective review of unresectable metastatic CRC patients treated ADAPT therapy and in those who also had PBMC CD133 mRNA measured. Results: Contrary to 5FU, which eliminates proliferating CRC cells via apoptosis but also stimulates stemness, celecoxib preferentially deplete CD133+ colon cells and exert potent stemness inhibition via rapid tumor necrosis by perturbing hypoxia and energy metabolism via CA-IX. Following response to first-line chemotherapy, ADAPT strategy plus radiation improved CR or near CR rate to 49/126 (40%) in unresectable CRC patients whose median survival had reached 92.7 months (95% CI, 53.5 months - not reached). Paradoxically, none surgical CR patients (n= 16) enjoyed 100% 5-year relapse free survival compared to 42% of surgical patients (p = 0.04). The PBMC CD133 mRNA in five long-term CR patients were 0.0024, 0.29, 0.5, 0.56, 2.96 respectively, all below previously reported cutoff value of 4.79 for recurrence and far below CD133 mRNA levels (28, 375, 3997, 15662, 83240) in none CR patients. Conclusions: ADAPT plus radiation preferentially targets colon CSC via hypoxia/CA-IX and improves clinical CR rate and molecular CR as measured by PBMC CD133 mRNA. We are actively interrogating the effects of ADAPT strategies in a phase II study funded by Gateway in CRC patients and in genetic CRC animal models.

The PPARγ agonist rosiglitazone enhances rat brown adipose tissue lipogenesis from glucose without altering glucose uptake

2009 ◽  
Vol 296 (5) ◽  
pp. R1327-R1335 ◽  
Author(s):  
William T. Festuccia ◽  
Pierre-Gilles Blanchard ◽  
Véronique Turcotte ◽  
Mathieu Laplante ◽  
Meltem Sariahmetoglu ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Glucose Uptake ◽  
Mrna Levels ◽  
Pparγ Agonist ◽  
Brown Adipose ◽  
Lipin 1 ◽  
The Impact

We investigated the mechanisms whereby peroxisome proliferator-activated receptor-γ (PPARγ) agonism affects glucose and lipid metabolism in brown adipose tissue (BAT) by studying the impact of PPARγ activation on BAT glucose uptake and metabolism, lipogenesis, and mRNA levels plus activities of enzymes involved in triacylglycerol (TAG) synthesis. Interscapular BAT of rats treated or not with rosiglitazone (15 mg·kg−1·day−1, 7 days) was evaluated in vivo for glucose uptake and lipogenesis and in vitro for glucose metabolism, gene expression, and activities of glycerolphosphate acyltransferase (GPAT), phosphatidate phosphatase-1 (PAP or lipin-1), and diacylglycerol acyltransferase (DGAT). Rosiglitazone increased BAT mass without affecting whole tissue glucose uptake. BAT glycogen content (−80%), its synthesis from glucose (−50%), and mRNA levels of UDP-glucose pyrophosphorylase (−40%), which generates UDP-linked glucose for glycogen synthesis, were all reduced by rosiglitazone. In contrast, BAT TAG-glycerol synthesis in vivo and glucose incorporation into TAG-glycerol in vitro were stimulated by the agonist along with the activities and mRNA levels of glycerol 3-phosphate-generating phosphoenolpyruvate carboxykinase and glycerokinase. Furthermore, rosiglitazone markedly increased the activities of GPAT and DGAT but not those of lipin-1-mediated PAP-1, enzymes involved in the sequential acylation of glycerol 3-phosphate and TAG synthesis. Because an adequate supply of fatty acids is essential for BAT nonshivering thermogenesis, the enhanced ability of BAT to synthesize TAG under PPARγ activation may constitute an important mechanism by which lipid substrates are stored in preparation for an eventual thermogenic activation.

The impact of hypoxia on plasminogen activator type-1 protein and mRNA levels in rat DS sarcoma in vitro and in vivo

2001 ◽  
Vol 37 ◽  
pp. S127
Author(s):  
M. Weinmann ◽  
O. Thews ◽  
T. Schröder ◽  
L. Plasswilm ◽  
P. Vaupel
Keyword(s):  
Plasminogen Activator ◽  
Mrna Levels ◽  
The Impact

Laboratory studies of the impact of calcite on in vitro and in vivo effects of coal dust: A potential preventive agent for coal workers' pneumoconiosis?

2012 ◽  
Vol 56 (3) ◽  
pp. 292-299 ◽  
Author(s):  
Meena Aladdin ◽  
Jinlong Jian ◽  
Qing Yang ◽  
Lung-Chi Chen ◽  
Robert B. Finkelman ◽  
...  
Keyword(s):  
Coal Dust ◽  
Laboratory Studies ◽  
Coal Workers Pneumoconiosis ◽  
Coal Workers ◽  
In Vivo Effects ◽  
The Impact

scholarly journals Trans-Activator Binding Site Context in RCNMV Modulates Subgenomic mRNA Transcription

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2252
Author(s):  
Jennifer S. H. Im ◽  
Laura R. Newburn ◽  
Gregory Kent ◽  
K. Andrew White
Keyword(s):  
Binding Site ◽  
Rna Structure ◽  
Red Clover ◽  
Mrna Levels ◽  
Mrna Transcription ◽  
Base Pairing ◽  
Independent Manner ◽  
The Impact

Many positive-sense RNA viruses transcribe subgenomic (sg) mRNAs during infections that template the translation of a subset of viral proteins. Red clover necrotic mosaic virus (RCNMV) expresses its capsid protein through the transcription of a sg mRNA from RNA1 genome segment. This transcription event is activated by an RNA structure formed by base pairing between a trans-activator (TA) in RNA2 and a trans-activator binding site (TABS) in RNA1. In this study, the impact of the structural context of the TABS in RNA1 on the TA–TABS interaction and sg mRNA transcription was investigated using in vitro and in vivo approaches. The results (i) generated RNA secondary structure models for the TA and TABS, (ii) revealed that the TABS is partially base paired with proximal upstream sequences, which limits TA access, (iii) demonstrated that the aforementioned intra-RNA1 base pairing involving the TABS modulates the TA–TABS interaction in vitro and sg mRNA levels during infections, and (iv) revealed that the TABS in RNA1 can be modified to mediate sg mRNA transcription in a TA-independent manner. These findings advance our understanding of transcriptional regulation in RCNMV and provide novel insights into the origin of the TA–TABS interaction.

scholarly journals Bisphenol A increases hydrogen peroxide generation by thyrocytes both in vivo and in vitro

2018 ◽  
Vol 7 (11) ◽  
pp. 1196-1207 ◽  
Author(s):  
Maurício Martins da Silva ◽  
Lueni Lopes Felix Xavier ◽  
Carlos Frederico Lima Gonçalves ◽  
Ana Paula Santos-Silva ◽  
Francisca Diana Paiva-Melo ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Bisphenol A ◽  
Thyroid Cell ◽  
Mrna Levels ◽  
Iodide Uptake ◽  
Hydrogen Peroxide Generation ◽  
Rat Thyroid ◽  
The Impact

Bisphenol A (BPA) is the most common monomer in polycarbonate plastics and an endocrine disruptor. Though some effects of BPA on thyroid hormone (TH) synthesis and action have been described, the impact of this compound on thyroid H2O2 generation remains elusive. H2O2 is a reactive oxygen species (ROS), which could have deleterious effect on thyrocytes if in excess. Therefore, herein we aimed at evaluating the effect of BPA exposition both in vivo and in vitro on H2O2 generation in thyrocytes, besides other essential steps for TH synthesis. Female Wistar rats were treated with vehicle (control) or BPA 40 mg/kg BW for 15 days, by gavage. We then evaluated thyroid iodide uptake, mediated by sodium-iodide symporter (NIS), thyroperoxidase (TPO) and dual oxidase (DOUX) activities (H2O2 generation). Hydrogen peroxide generation was increased, while iodide uptake and TPO activity were reduced by BPA exposition. We have also incubated the rat thyroid cell line PCCL3 with 10−9 M BPA and evaluated Nis and Duox mRNA levels, besides H2O2 generation. Similar to that found in vivo, BPA treatment also led to increased H2O2 generation in PCCL3. Nis mRNA levels were reduced and Duox2 mRNA levels were increased in BPA-exposed cells. To evaluate the importance of oxidative stress on BPA-induced Nis reduction, PCCL3 was treated with BPA in association to N-acetylcysteine, an antioxidant, which reversed the effect of BPA on Nis. Our data suggest that BPA increases ROS production in thyrocytes, what could lead to oxidative damage thus possibly predisposing to thyroid disease.

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