Developmental Changes in the Pattern of Ghrelin’s Acyl Modification and the Levels of Acyl-Modified Ghrelins in Murine Stomach

Abstract Ghrelin is an acylated peptide hormone secreted primarily from endocrine cells in the stomach. The major active form of ghrelin is a 28-amino acid peptide with an n-octanoyl modification at Ser3 (n-octanoyl ghrelin), which is essential for its activity. In addition to n-octanoyl ghrelin, other forms of ghrelin peptide exist, including des-acyl ghrelin, which lacks an acyl modification, and other minor acylated ghrelin species, such as n-decanoyl ghrelin, whose Ser3 residue is modified by n-decanoic acid. Multiple reports have identified various physiological functions of ghrelin. However, until now, there have been no reports that explore the process of ghrelin acyl modification, and only a few studies have compared the levels of des-acyl, n-octanoyl, and/or other minor populations of acylated ghrelin peptides. In this study we report that the amount of n-octanoyl ghrelin in murine stomachs increases gradually during the suckling period to a maximal level at 3 wk of age and falls sharply after the initiation of weaning. However, the concentration (picomoles per milligram of wet weight tissue) of total ghrelin, which includes des-acyl and all acylated forms of ghrelin peptides with intact C termini in murine stomach, remains unchanged across this suckling-weaning transition. Prematurely weaned mice exhibited a significant decrease in the amount of n-octanoyl or n-decanoyl ghrelin in the stomach. Orally ingested glyceryl trioctanoate, a medium-chain triacylglyceride rich in milk lipids, significantly increased the level of n-octanoyl-modified ghrelin in murine stomach. Fluctuations in the proportion of this biologically active, acyl-modified ghrelin could contribute to or be influenced by the change in energy metabolism during the suckling-weaning transition.

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Role for central ghrelin in food intake and secretion profile of stomach ghrelin in rats

Journal of Endocrinology ◽

10.1677/joe.0.1740283 ◽

2002 ◽

Vol 174 (2) ◽

pp. 283-288 ◽

Cited By ~ 163

Author(s):

N Murakami ◽

T Hayashida ◽

T Kuroiwa ◽

K Nakahara ◽

T Ida ◽

...

Keyword(s):

Body Weight ◽

Food Intake ◽

Body Weight Gain ◽

Intestinal Hormones ◽

Amino Acid Peptide ◽

Secretion Profile ◽

Total Ghrelin ◽

Acyl Ghrelin ◽

Minimum Volumes ◽

Ghrelin Secretion

Ghrelin, a 28-amino-acid peptide, has recently been isolated from the rat stomach as an endogenous ligand for the GH secretagogue receptor. We have reported previously that central or peripheral administration of ghrelin stimulates food intake, and the secretion of GH and gastric acid in rats. In the present study, we investigated how much endogenous centrally released ghrelin is involved in the control of food intake and body weight gain. We also examined the profile of ghrelin secretion from the stomach by RIA using two kinds of anti-ghrelin antiserum, one raised against the N-terminal ([Cys(12)]-ghrelin[1-11]) region and one raised against the C-terminal ([Cys(0)]-ghrelin [13-28]) region of the peptide. The former antibody recognizes specifically ghrelin with n- octanoylated Ser 3 (acyl ghrelin), and does not recognize des-acyl ghrelin. The latter also recognizes des-acyl ghrelin (i.e. total ghrelin). Intracerebroventricular treatment with the anti-ghrelin antiserum against the N-terminal region twice a day for 5 days decreased significantly both daily food intake and body weight. Des-acyl ghrelin levels were significantly higher in the gastric vein than in the trunk. Either fasting for 12 h, administration of gastrin or cholecystokinin resulted in increase of both acyl and des-acyl ghrelin levels. The ghrelin levels exhibited a diurnal pattern, with the bimodal peaks occurring before dark and light periods. These two peaks were consistent with maximum and minimum volumes of gastric content respectively. These results suggest that (1) endogenous centrally released ghrelin participates in the regulation of food intake and body weight, (2) acyl ghrelin is secreted from the stomach, (3) intestinal hormones stimulate ghrelin release from the stomach, and (4) regulation of the diurnal rhythm of ghrelin is complex, since ghrelin secretion is augmented under conditions of both gastric emptying and filling.

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Potential of Bacillus cereus for Producing an Emetic Toxin, Cereulide, in Bakery Products: Quantitative Analysis by Chemical and Biological Methods

Journal of Food Protection ◽

10.4315/0362-028x-66.6.1047 ◽

2003 ◽

Vol 66 (6) ◽

pp. 1047-1054 ◽

Cited By ~ 42

Author(s):

ELINA L. JÄÄSKELÄINEN ◽

MAX M. HÄGGBLOM ◽

MARIA A. ANDERSSON ◽

LIISA VANNE ◽

MIRJA S. SALKINOJA-SALONEN

Keyword(s):

Quantitative Analysis ◽

Bacillus Cereus ◽

Active Form ◽

Food Poisoning ◽

Direct Analysis ◽

Biologically Active ◽

Bakery Products ◽

Chemical Assay ◽

Wet Weight ◽

Biological Methods

A method for the direct quantitative analysis of cereulide, the emetic toxin of Bacillus cereus, in bakery products was developed. The analysis was based on robotized extraction followed by quantitation of cereulide by liquid chromatography–mass spectrometry and an assay of toxicity by the boar sperm motility inhibition test. The bioassay and the chemical assay gave comparable results, demonstrating that the extracted cereulide was in a biologically active form. Cereulide was formed when cereulide-producing B. cereus strains were present at ≥106 CFU/g in products with water activity values of >0.953 and pHs of >5.6. Rice-containing pastries accumulated high contents of cereulide (0.3 to 5.5 μg/g [wet weight]) when stored at nonrefrigeration temperatures (21 to 23°C). Cereulide was not formed in products stored at refrigeration temperatures (4 to 8°C). Cereulide is not inactivated by heating during food processing. Therefore, direct analysis of this toxin in food is preferable to cultivating methods for assessing the risk of food poisoning by emetic B. cereus.

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Hypothalamic Injection of Oxyntomodulin Suppresses Circulating Ghrelin-Like Immunoreactivity

Endocrinology ◽

10.1210/en.2008-0796 ◽

2009 ◽

Vol 150 (8) ◽

pp. 3513-3520 ◽

Cited By ~ 12

Author(s):

Michael Patterson ◽

Kevin G. Murphy ◽

Sejal R. Patel ◽

Neekhil A. Patel ◽

Hannah C. Greenwood ◽

...

Keyword(s):

Lateral Ventricle ◽

Arcuate Nucleus ◽

Gut Hormones ◽

Peptide Hormone ◽

Acylated Ghrelin ◽

Gh Secretion ◽

Final Study ◽

Total Ghrelin ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1

Ghrelin is a gastric peptide that regulates appetite and GH secretion. Circulating ghrelin levels are elevated by fasting and suppressed postprandially. However, the mechanisms regulating circulating ghrelin levels are unclear. Oxyntomodulin is an anorexic peptide hormone released from L cells in the gut. We investigated the effects of intracerebroventricular (icv) administration of oxyntomodulin on circulating ghrelin levels. The icv administration of 1, 3, or 10 nmol oxyntomodulin reduced circulating acylated and total (acylated and des-acylated) ghrelin 60 min after icv injection. Administration of 1 nmol oxyntomodulin directly into the arcuate nucleus of the hypothalamus significantly reduced total and acylated ghrelin levels, and administration of 3 nmol oxyntomodulin into the lateral ventricle induced c-fos mRNA expression in arcuate nucleus neurons expressing the glucagon-like peptide-1 (GLP-1) receptor. In a final study, the reduction in total ghrelin observed after icv injection of 3 nmol oxyntomodulin was blocked by coadministration of the GLP-1 receptor antagonist exendin (9–39). These studies suggest oxyntomodulin reduces peripheral ghrelin levels via GLP-1 receptor-dependent hypothalamic pathways. Postprandial release of anorexic gut hormones may thus act centrally to contribute to the postprandial reduction in circulating ghrelin.

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Ingested Medium-Chain Fatty Acids Are Directly Utilized for the Acyl Modification of Ghrelin

Endocrinology ◽

10.1210/en.2004-0695 ◽

2005 ◽

Vol 146 (5) ◽

pp. 2255-2264 ◽

Cited By ~ 171

Author(s):

Yoshihiro Nishi ◽

Hiroshi Hiejima ◽

Hiroshi Hosoda ◽

Hiroyuki Kaiya ◽

Kenji Mori ◽

...

Keyword(s):

Fatty Acids ◽

Active Form ◽

Carbon Chain ◽

Medium Chain ◽

Medium Chain Fatty Acids ◽

Amino Acid Peptide ◽

Acyl Ghrelin ◽

Chain Lengths ◽

Fuel Preference ◽

Chain Fatty Acids

Abstract Ghrelin, an acylated brain and gut peptide, is primarily produced by endocrine cells of the gastric mucosa for secretion into the circulation. The major active form of ghrelin is a 28-amino-acid peptide containing an n-octanoyl modification at serine that is essential for activity. Studies have identified multiple physiological functions for ghrelin, including GH release, appetite stimulation, and metabolic fuel preference. Until now, there has not been any report detailing the mechanism of ghrelin acyl modification. Here we report that ingestion of either medium-chain fatty acids (MCFAs) or medium-chain triacylglycerols (MCTs) increased the stomach concentrations of acylated ghrelin without changing the total (acyl- and des-acyl-) ghrelin amounts. After ingestion of either MCFAs or MCTs, the carbon chain lengths of the acyl groups attached to nascent ghrelin molecules corresponded to that of the ingested MCFAs or MCTs. Ghrelin peptides modified with n-butyryl or n-palmitoyl groups, however, could not be detected after ingestion of the corresponding short-chain or long-chain fatty acids, respectively. Moreover, n-heptanoyl ghrelin, an unnatural form of ghrelin, could be detected in the stomach of mice after ingestion of either n-heptanoic acid or glyceryl triheptanoate. These findings indicate that ingested medium-chain fatty acids are directly used for the acylation of ghrelin.

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A Pilot Screen of a Novel Peptide Hormone Library Identified Candidate GPR83 Ligands

SLAS DISCOVERY Advancing Life Sciences ◽

10.1177/2472555220934807 ◽

2020 ◽

Vol 25 (9) ◽

pp. 1047-1063

Author(s):

Nathan A. Sallee ◽

Ernestine Lee ◽

Atossa Leffert ◽

Silvia Ramirez ◽

Arthur D. Brace ◽

...

Keyword(s):

Secretory Pathway ◽

Cell Function ◽

Active Form ◽

Peptide Hormone ◽

Biologically Active ◽

Host Cells ◽

Functional Screening ◽

Posttranslational Processing ◽

Regulated Secretory Pathway ◽

G Protein Coupled

The identification of novel peptide hormones by functional screening is challenging because posttranslational processing is frequently required to generate biologically active hormones from inactive precursors. We developed an approach for functional screening of novel potential hormones by expressing them in endocrine host cells competent for posttranslational processing. Candidate preprohormones were selected by bioinformatics analysis, and stable endocrine host cell lines were engineered to express the preprohormones. The production of mature hormones was demonstrated by including the preprohormones insulin and glucagon, which require the regulated secretory pathway for production of the active forms. As proof of concept, we screened a set of G-protein-coupled receptors (GPCRs) and identified protein FAM237A as a specific activator of GPR83, a GPCR implicated in central nervous system and regulatory T-cell function. We identified the active form of FAM237A as a C-terminally cleaved, amidated 9 kDa secreted protein. The related protein FAM237B, which is 64% homologous to FAM237A, demonstrated similar posttranslational modification and activation of GPR83, albeit with reduced potency. These results demonstrate that our approach is capable of identifying and characterizing novel hormones that require processing for activity.

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Ghrelin and acyl ghrelin in preterm infants and maternal blood: relationship with endocrine and anthropometric measures

Acta Endocrinologica ◽

10.1530/eje-07-0410 ◽

2008 ◽

Vol 158 (1) ◽

pp. 27-33 ◽

Cited By ~ 14

Author(s):

Éva Lányi ◽

Ákos Várnagy ◽

Kálmán A Kovács ◽

Tamás Csermely ◽

Mária Szász ◽

...

Keyword(s):

Preterm Infants ◽

Umbilical Vein ◽

Multivariate Regression Analysis ◽

Maternal Blood ◽

Acylated Ghrelin ◽

Anthropometric Measures ◽

Ghrelin Concentration ◽

Anthropometric Features ◽

Total Ghrelin ◽

Acyl Ghrelin

ObjectiveThe objective of the present study was to examine the association of acylated and total ghrelin levels at birth in preterm infants with anthropometric features and with related hormones in infants and their mothers.DesignProspective, descriptive study.MethodsIn total 23 pregnant women and their 26 preterm infants were involved in the study (3 twin pregnancies; gestational age, 25–35 weeks). Maternal and umbilical vein blood samples were taken after the delivery. Serum acylated and total ghrelin, leptin, cortisol, insulin, GH, and glucose were determined.ResultsThe mean level of acylated ghrelin concentration was higher in the maternal than in the cord blood (P<0.01) and there was a significant correlation between the fetal and maternal acylated ghrelin levels (P<0.01). The total ghrelin concentration was higher in neonates than in mothers (P<0.01), but there was no correlation between them. The multivariate regression analysis for fetal acylated and maternal total ghrelin as dependent variables shows that the fetal acylated ghrelin has two independent predictors, the maternal acylated ghrelin (P<0.01) and the fetal cortisol (P<0.05), whereas the maternal total ghrelin has only one independent predictor, the maternal glucose (P<0.05).ConclusionsThese data provide the first evidence that umbilical cord acylated ghrelin concentrations are lower than in maternal blood and support the hypothesis that the acylation process in the fetus is partly affected by cortisol and the placenta may play a role in this process.

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Processing and Characterization of Recombinant von Willebrand Factor Expressed in Different Cell Types Using a Vaccinia Virus Vector

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648398 ◽

1992 ◽

Vol 67 (01) ◽

pp. 154-160 ◽

Cited By ~ 14

Author(s):

P Meulien ◽

M Nishino ◽

C Mazurier ◽

K Dott ◽

G Piétu ◽

...

Keyword(s):

Vaccinia Virus ◽

Von Willebrand Factor ◽

Human Fibroblasts ◽

Active Form ◽

Cell Types ◽

Biologically Active ◽

L Cells ◽

Von Willebrand ◽

Different Cell Types ◽

Willebrand Factor

SummaryThe cloning of the cDNA encoding von Willebrand factor (vWF) has revealed that it is synthesized as a large precursor (pre-pro-vWF) molecule and it is now clear that the prosequence or vWAgll is responsible for the intracellular multimerization of vWF. We have cloned the complete vWF cDNA and expressed it using a recombinant vaccinia virus as vector. We have characterized the structure and function of the recombinant vWF (rvWF) secreted from five different cell types: baby hamster kidney (BHK), Chinese hamster ovary (CHO), human fibroblasts (143B), mouse fibroblasts (L) and primary embryonic chicken cells. Forty-eight hours after infection, the quantity of vWF antigen found in the cell supernatant varied from 3 to 12 U/dl depending on the cell type. By SDS-agarose gel electrophoresis, the percentage of high molecular weight forms of vWF varied from 39 to 49% relative to normal plasma for BHK, CHO, 143B and chicken cells but was less than 10% for L cells. In all cell types, the two anodic subbands of each multimer were missing. The two cathodic subbands were easily detected only in BHK and L cells. By SDS-PAGE of reduced samples, pro-vWF was present in similar quantity to the fully processed vWF subunit in L cells, present in moderate amounts in BHK and CHO and in very low amounts in 143B and chicken cells. rvWF from all cells bound to collagen and to platelets in the presence of ristocetin, the latter showing a high correlation between binding efficiency and degree of multimerization. rvWF from all cells was also shown to bind to purified FVIII and in this case binding appeared to be independent of the degree of multimerization. We conclude that whereas vWF is naturally synthesized only by endothelial cells and megakaryocytes, it can be expressed in a biologically active form from various other cell types.

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Innovative approaches to the correction of chronotrope status of pregnant and lactating women

HEALTH OF WOMAN ◽

10.15574/hw.2016.114.37 ◽

2016 ◽

pp. 37-40

Author(s):

S.I. Zhuk ◽

◽

K.K. Bondarenko ◽

Keyword(s):

Folic Acid ◽

Neural Tube ◽

Active Form ◽

Biologically Active ◽

Lactating Women ◽

Pathological Conditions ◽

Prevention And Treatment ◽

The Impact ◽

High Bioavailability ◽

Key Words Mthfr

Most recent studies show the impact of violations in the metabolism of folate and metin period in the pathogenesis of neural tube defects (NTD) of the fetus. Metafolin has a number of advantages, which primarily includes direct intake of substances in biologically active form and the optimum effect, even in the case when the patient homozygote and/or heterozygote genotype 677С T polymorphism in MTHFR. With the aim of prevention and treatment of various pathological conditions related to folate deficiency during pregnancy, it is advisable to apply vitamin-mineral complexes, containing metafolin - active form of folate with high bioavailability. Key words: MTHFR, metafolin, folic acid, pregnancy.

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Natural Antioxidants in Anemia Treatment

International Journal of Molecular Sciences ◽

10.3390/ijms22041883 ◽

2021 ◽

Vol 22 (4) ◽

pp. 1883

Author(s):

Coralia Cotoraci ◽

Alina Ciceu ◽

Alciona Sasu ◽

Anca Hermenean

Keyword(s):

Plant Extracts ◽

Iron Homeostasis ◽

Therapeutic Potential ◽

Public Health Problem ◽

Natural Antioxidants ◽

Peptide Hormone ◽

Biologically Active ◽

Major Public Health Problem ◽

Stomach Pain

Anemia, characterized by a decrease of the hemoglobin level in the blood and a reduction in carrying capacity of oxygen, is a major public health problem which affects people of all ages. The methods used to treat anemia are blood transfusion and oral administration of iron-based supplements, but these treatments are associated with a number of side effects, such as nausea, vomiting, constipation, and stomach pain, which limit its long-term use. In addition, oral iron supplements are poorly absorbed in the intestinal tract, due to overexpression of hepcidin, a peptide hormone that plays a central role in iron homeostasis. In this review, we conducted an analysis of the literature on biologically active compounds and plant extracts used in the treatment of various types of anemia. The purpose of this review is to provide up-to-date information on the use of these compounds and plant extracts, in order to explore their therapeutic potential. The advantage of using them is that they are available from natural resources and can be used as main, alternative, or adjuvant therapies in many diseases, such as various types of anemia.

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Folate in Red Rhapsody Strawberry—Content and Storage Stability.

Proceedings ◽

10.3390/foods_2020-07670 ◽

2020 ◽

Vol 70 (1) ◽

pp. 47

Author(s):

Julius Rami ◽

Caroline Dumler ◽

Nadine Weber ◽

Michael Rychlik ◽

Gabriele Netzel ◽

...

Keyword(s):

Storage Stability ◽

Active Form ◽

Food Composition ◽

Biologically Active ◽

Stable Isotope Dilution ◽

Isotope Dilution Assay ◽

C Storage ◽

Vitamin B9 ◽

Adults And Children ◽

And Storage

Folate (Vitamin B9) is critical for a range of biological functions in adults and children, including DNA, protein and neurotransmitter synthesis. It is also essential for the healthy development of the fetus in early pregnancy and for the prevention of neural tube defects, such as spina bifida. Strawberries are considered a tasty and healthy fruit consumed all over the world and may potentially be an important dietary source of natural folates. However, the relative importance of strawberry as a dietary source will depend on the total folate concentration, vitamer profile, storage stability and bioavailability to humans. Red Rhapsody, an important commercial strawberry cultivar in Australia, was screened for its folate content and storage stability by stable isotope dilution assay (SIDA). Total folate content ranged from 90–118 μg/100 g fresh weight (fw), which was well above the value in the Australian Food Composition Database (39 μg/100 g fw). 5-Methyltetrahydrofolate, the biologically active form in humans, was the principal vitamer present. Furthermore, folate remained relatively stable during refrigerated (4 °C) storage (loss of only 28% after 14 days of storage). This information is relevant for consumers since the inherent perishability of strawberry fruit makes refrigerated storage common practice in Australian households.

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