scholarly journals Effect of IGF-I on serine metabolism in fetal sheep

2000 ◽  
Vol 165 (2) ◽  
pp. 261-269 ◽  
Author(s):  
EC Jensen ◽  
P van Zijl ◽  
PC Evans ◽  
JE Harding
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Amino Acid Uptake ◽  
Acid Synthesis ◽  
Acid Oxidation ◽  
Acid Uptake ◽  
Amino Acid Synthesis ◽  
Fetal Sheep ◽  
Igf I

Acute infusion of IGF-I to the fetus has been shown to inhibit amino acid oxidation and appears to increase fetoplacental amino acid uptake. This study was designed to investigate further the effects of IGF-I on fetal amino acid metabolism. Radiolabeled serine was used to test the hypothesis that fetal IGF-I infusion enhances serine uptake into the fetus and/or placenta and inhibits serine oxidation. Eight fetal sheep were studied at 127 days of gestation before and during a 4-h infusion of IGF-I (50 microg/h per kg). During the infusion there was no change in uptake of serine or its oxidation by fetus or placenta. However, both uptake and oxidation of serine and glycine decreased in the fetal carcass. There was also a decrease in fetal blood serine and glycine concentrations which could indicate a decrease in protein breakdown, although reduced amino acid synthesis cannot be excluded. Thus IGF-I appeared to influence the distribution of these amino acids as oxidative substrates between different fetal tissues. In addition, fetal IGF-I infusion increased the conversion of serine to glycine which is likely to have increased the availability of one-carbon groups for biosynthesis. Our data provide further evidence that IGF-I plays a role in the regulation of fetoplacental amino acid metabolism.

scholarly journals Prolonged amino acid infusion into intrauterine growth-restricted fetal sheep increases leucine oxidation rates

2018 ◽  
Vol 315 (6) ◽  
pp. E1143-E1153 ◽  
Author(s):  
Sandra G. Wai ◽  
Paul J. Rozance ◽  
Stephanie R. Wesolowski ◽  
William W. Hay ◽  
Laura D. Brown
Keyword(s):  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Fetal Sheep ◽  
Acid Infusion ◽  
Amino Acid Infusion ◽  
Intrauterine Growth ◽  
Leucine Oxidation ◽  
Fetal Plasma ◽  
Oxidation Rates

Overcoming impaired growth in an intrauterine growth-restricted (IUGR) fetus has potential to improve neonatal morbidity, long-term growth, and metabolic health outcomes. The extent to which fetal anabolic capacity persists as the IUGR condition progresses is not known. We subjected fetal sheep to chronic placental insufficiency and tested whether prolonged amino acid infusion would increase protein accretion in these IUGR fetuses. IUGR fetal sheep were infused for 10 days with either mixed amino acids providing ~2 g·kg−1·day−1 (IUGR-AA) or saline (IUGR-Sal) during late gestation. At the end of the infusion, fetal plasma leucine, isoleucine, lysine, methionine, and arginine concentrations were higher in the IUGR-AA than IUGR-Sal group ( P < 0.05). Fetal plasma glucose, oxygen, insulin, IGF-1, cortisol, and norepinephrine concentrations were similar between IUGR groups, but glucagon concentrations were fourfold higher in the IUGR-AA group ( P < 0.05). Net umbilical amino acid uptake rate did not differ between IUGR groups; thus the total amino acid delivery rate (net umbilical amino acid uptake + infusion rate) was higher in the IUGR-AA than IUGR-Sal group (30 ± 4 vs. 19 ± 1 μmol·kg−1·min−1, P < 0.05). Net umbilical glucose, lactate, and oxygen uptake rates were similar between IUGR groups. Fetal leucine oxidation rate, measured using a leucine tracer, was higher in the IUGR-AA than IUGR-Sal group (2.5 ± 0.3 vs. 1.7 ± 0.3 μmol·kg−1·min−1, P < 0.05). Fetal protein accretion rate was not statistically different between the IUGR groups (1.6 ± 0.4 and 0.8 ± 0.3 μmol·kg−1·min−1 in IUGR-AA and IUGR-Sal, respectively) due to variability in response to amino acids. Prolonged amino acid infusion into IUGR fetal sheep increased leucine oxidation rates with variable anabolic response.

Effects of insulin, insulin-like growth factor-I (IGF-I) and progesterone on glucose and amino acid uptake in Xenopus laevis oocytes

1991 ◽  
Vol 75 (2) ◽  
pp. 133-139 ◽  
Author(s):  
Pierre Hainaut ◽  
Aline Kowalski ◽  
Yannick Le Marchand-Brustel ◽  
Sophie Giorgetti ◽  
Nadine Gautier ◽  
...  
Keyword(s):  
Amino Acid ◽  
Growth Factor ◽  
Xenopus Laevis ◽  
Amino Acid Uptake ◽  
Xenopus Laevis Oocytes ◽  
Acid Uptake ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Fetal hepatic and umbilical uptakes of glucogenic substrates during a glucagon-somatostatin infusion

2002 ◽  
Vol 282 (3) ◽  
pp. E542-E550 ◽  
Author(s):  
Cecilia Teng ◽  
Frederick C. Battaglia ◽  
Giacomo Meschia ◽  
Michael R. Narkewicz ◽  
Randall B. Wilkening
Keyword(s):  
Amino Acid ◽  
Acid Metabolism ◽  
Fetal Liver ◽  
Amino Acid Uptake ◽  
Hepatic Uptake ◽  
High Rate ◽  
Acid Uptake ◽  
Glucose Carbon ◽  
Ovine Fetal ◽  
Equivalent Reduction

To test the hypothesis that fetal hepatic glutamate output diverts the products of hepatic amino acid metabolism from hepatic gluconeogenesis, ovine fetal hepatic and umbilical uptakes of glucose and glucogenic substrates were measured before and during fetal glucagon-somatostatin (GS) infusion and during the combined infusion of GS, alanine, glutamine, and arginine. Before the infusions, hepatic uptake of lactate, alanine, glutamine, arginine, and other substrates was accompanied by hepatic output of pyruvate, aspartate, serine, glutamate, and ornithine. The GS infusion induced hepatic output of 1.00 ± 0.07 mol glucose carbon/mol O2 uptake, an equivalent reduction in hepatic output of pyruvate and glutamate carbon, a decrease in umbilical glucose uptake and placental uptake of fetal glutamate, an increase in hepatic alanine and arginine clearances, and a decrease in umbilical alanine, glutamine, and arginine uptakes. The latter result suggests that glucagon inhibits umbilical amino acid uptake. We conclude that fetal hepatic pyruvate and glutamate output is part of an adaptation to placental function that requires the fetal liver to maintain both a high rate of catabolism of glucogenic substrates and a low rate of gluconeogenesis.

scholarly journals Structural disruption of the trans-Golgi network does not interfere with the acute stimulation of glucose and amino acid uptake by insulin-like growth factor I in muscle cells

1994 ◽  
Vol 297 (2) ◽  
pp. 289-295 ◽  
Author(s):  
H S Hundal ◽  
P J Bilan ◽  
T Tsakiridis ◽  
A Marette ◽  
A Klip
Keyword(s):  
Amino Acid ◽  
Brefeldin A ◽  
Glucose Transporters ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Trans Golgi Network ◽  
Maximal Activation ◽  
Igf I ◽  
Golgi Network ◽  
Stimulation Of

The effects of insulin-like growth factor I (IGF-I) on glucose and amino acid uptake were investigated in fully differentiated L6 muscle cells, in order to determine whether the two processes are functionally related. Transport of both glucose and amino acid (methylaminoisobutyric acid, MeAIB) was activated rapidly in response to IGF-I. Stimulation reached a peak within 30 min and was sustained for up to 90 min. Maximal activation of either glucose or MeAIB transport was achieved at 3 nM IGF-I; the half-maximal activation (ED50) of glucose transport was at 107 pM and that of MeAIB transport was at 36 pM. Stimulation of amino acid uptake occurred in the absence or presence of glucose, suggesting that this response is not secondary to increased glucose intake. Incubation of cells for 1 h with Brefeldin A (5 micrograms/ml), which disassembles the Golgi apparatus and inhibits the secretory pathway in eukaryotic cells, had no effect on the acute IGF-I activation of glucose and MeAIB transport. Moreover, Brefeldin A caused wide redistribution of the trans-Golgi antigen TGN38, as assessed by subcellular fractionation, without affecting the distribution of glucose transporters. The finding that the degree of activation, time response and sensitivity to IGF-I and Brefeldin A were similar for both glucose and MeAIB transport suggests commonalities in the IGF-I mechanism of recruitment of glucose transporters and stimulation of amino acid transport through System A. An integral trans-Golgi network does not appear to be required for the acute IGF-I stimulation of glucose or amino acid transport, even though stimulation of glucose transport occurs through recruitment of glucose transporters from intracellular stores in these cells. We propose that the donor site of glucose transporters (and perhaps of amino acid transporters) involved in the acute response to IGF-I lies beyond the trans-Golgi network, perhaps in an endosomal compartment in close proximity to the plasma membrane.

scholarly journals Role of the DksA-Like Protein in the Pathogenesis and Diverse Metabolic Activity of Campylobacter jejuni

2008 ◽  
Vol 190 (13) ◽  
pp. 4512-4520 ◽  
Author(s):  
Jiae Yun ◽  
Byeonghwa Jeon ◽  
Yi-Wen Barton ◽  
Paul Plummer ◽  
Qijing Zhang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Campylobacter Jejuni ◽  
Pathogenic Bacteria ◽  
Acid Metabolism ◽  
Acid Synthesis ◽  
Regulatory Role ◽  
Intestinal Cells ◽  
Amino Acid Synthesis ◽  
Metabolic Reactions

ABSTRACT DksA is well known for its regulatory role in the transcription of rRNA and genes involved in amino acid synthesis in many bacteria. DksA has also been reported to control expression of virulence genes in pathogenic bacteria. Here, we elucidated the roles of a DksA-like protein (CJJ81176_0160, Cj0125c) in the pathogenesis of Campylobacter jejuni. As in other bacteria, transcription of stable RNA was repressed by the DksA-like protein under stress conditions in C. jejuni. Transcriptomic and proteomic analyses of C. jejuni 81-176 and an isogenic mutant lacking the DksA-like protein showed differential expression of many genes involved in amino acid metabolism, iron-related metabolism, and other metabolic reactions. Also, the C. jejuni DksA-like protein mutant exhibited a decreased ability to invade intestinal cells and induce release of interleukin-8 from intestinal cells. These results suggest that the DksA-like protein plays an important regulatory role in diverse metabolic events and the virulence of C. jejuni.

scholarly journals Impaired amino acid metabolism contributes to fasting-induced hypoglycemia in fatty acid oxidation defects

2013 ◽  
Vol 22 (25) ◽  
pp. 5249-5261 ◽  
Author(s):  
Sander M. Houten ◽  
Hilde Herrema ◽  
Heleen te Brinke ◽  
Simone Denis ◽  
Jos P.N. Ruiter ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Fatty Acid Oxidation ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Acid Oxidation

scholarly journals Macrophage metabolism in the intestine is compartment-specific and regulated by the microbiota

2021 ◽  
Author(s):  
Nicholas A Scott ◽  
Melissa Lawson ◽  
Ryan Hodgetts ◽  
Lindsay J Hall ◽  
Elizabeth Mann
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Synthesis ◽  
Fatty Acid Uptake ◽  
Vital Role ◽  
Antibiotic Administration ◽  
Acid Uptake ◽  
Large Neutral Amino Acid ◽  
Metabolic Functions

Intestinal macrophages play a vital role in the maintenance of gut homeostasis through signals derived from the microbiota. We previously demonstrated that microbial-derived metabolites can shape the metabolic functions of macrophages. Here, we show that antibiotic-induced disruption of the intestinal microbiota dramatically alters both the local metabolite environment, and the metabolic functions of macrophages in the colon. Broad-spectrum antibiotic administration in mice increased expression of the large neutral amino acid transporter and accordingly, amino acid uptake. Subsequently, antibiotic administration enhanced the metabolic functions of colonic macrophages, increasing phosphorylation of components of mammalian/mechanistic target of rapamycin (mTOR) signalling pathways, increasing expression of genes involved in glycolysis and oxidative phosphorylation (OXPHOS), increasing mitochondrial function and increased levels of ECAR and OCR as a direct measure of glycolysis and OXPHOS. Small bowel macrophages were less metabolically active than in the colon, with macrophage metabolism being independent of the microbiota. Finally, we reveal tissue resident Tim4+ CD4+ macrophages exhibit enhanced fatty acid uptake alongside reduced fatty acid synthesis compared to their recruited counterparts. Thus the microbiota shapes gut macrophage metabolism in a compartment-specific manner, with important implications for functions when monocyte recruitment and macrophage differentiation.

scholarly journals Effects of nitrogen levels on gene expression and amino acid metabolism in Welsh onion

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Chen Zhao ◽  
Guanchu Ma ◽  
Lin Zhou ◽  
Song Zhang ◽  
Le Su ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Protein Biosynthesis ◽  
Amino Acid Content ◽  
Growth And Yield ◽  
Welsh Onion ◽  
Amino Acid Synthesis

Abstract Background Welsh onion constitutes an important crop due to its benefits in traditional medicine. Nitrogen is an important nutrient for plant growth and yield; however, little is known about its influence on the mechanisms of Welsh onion regulation genes. In this study, we introduced a gene expression and amino acid analysis of Welsh onion treated with different concentrations of nitrogen (N0, N1, and N2 at 0 kg/ha, 130 kg/ha, and 260 kg/ha, respectively). Results Approximately 1,665 genes were differentially regulated with different concentrations of nitrogen. Gene ontology enrichment analysis revealed that the genes involved in metabolic processes, protein biosynthesis, and transportation of amino acids were highly represented. KEGG analysis indicated that the pathways were related to amino acid metabolism, cysteine, beta-alanine, arginine, proline, and glutathione. Differential gene expression in response to varying nitrogen concentrations resulted in different amino acid content. A close relationship between gene expression and the content of amino acids was observed. Conclusions This work examined the effects of nitrogen on gene expression and amino acid synthesis and provides important evidence on the efficient use of nitrogen in Welsh onion.

Amino acid metabolism by hepatocytes in a hybrid liver support bioreactor

1994 ◽  
Vol 17 (12) ◽  
pp. 663-669 ◽  
Author(s):  
M. Fuchs ◽  
J. Gerlach ◽  
J. Encke ◽  
J. Unger ◽  
M. Smith ◽  
...  
Keyword(s):  
Amino Acid ◽  
Acid Metabolism ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Liver Support ◽  
Volume Increase ◽  
Liver Support System ◽  
Amino Acid Turnover ◽  
Acid Release ◽  
Branched Chain

The amino acid patterns of medium perfusate in a liver cell bioreactor developed for a hybrid liver support system have been measured. There were considerable changes in the concentrations of glutamic acid, glutamine, alanine, arginine, ornithine and branched chain amino acids during the first 10 days which is indicative of dynamic cellular metabolism. From day 15, steady state conditions of nitrogen metabolism are reflected by stable amino acid turnover. Monitoring of urea, K+, and P-450 activity suggests that hepatocytes have switched to a stable protein synthesis with a general amino acid uptake and keto acid release following cell volume increase

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