Effects of the Oral Administration of Glucose and Amino Acids on Hepatic Lipogenesis in Chicks Fasted after Having Been Fed a High-Carbohydrate or a High-Protein Diet

1. Inter-organ relationships between glucose, lactate and amino acids were studied by determination of plasma concentrations in different blood vessels of anaesthetized rats fed on either a high-carbohydrate diet [13% (w/w) casein, 79% (w/w) starch] or a high-protein diet [50% (w/w) casein, 42% (w/w) starch]. The period of food intake was limited (09:00–17:00h), and blood was collected 4h after the start of this period (13:00h). 2. Glucose absorption was considerable only in rats fed on a high-carbohydrate diet. Portal-vein–artery differences in plasma lactate concentration were higher in rats fed on this diet, but not proportional to glucose absorption. Aspartate, glutamate and glutamine were apparently converted into alanine, but when dietary protein intake was high, a net absorption of glutamine occurred. 3. The liver removed glucose from the blood in rats fed on a high-carbohydrate diet, but glucose was released into the blood in rats fed on the high-protein diet, probably as a result of gluconeogenesis. Lactate uptake was very low when amino acid availability was high. 4. In rats on a high-protein diet, increased uptake of amino acids, except for ornithine, was associated with a rise in portal-vein plasma concentrations, and in many cases with a decrease in hepatic concentrations. 5. Hepatic concentrations of pyruvate and 2-oxo-glutarate decreased without a concomitant change in the concentrations of lactate and malate in rats fed on the high-protein diet, in spite of an increased supply of pyruvate precursors (e.g. alanine, serine, glycine), suggesting increased pyruvate transport into mitochondria. 6. High postprandial concentrations of plasma glucose and lactate resulted in high uptakes of these metabolites in peripheral tissues of rats on both diets. Glutamine was released peripherally in both cases, whereas alanine was taken up in rats fed on a high-carbohydrate diet, but released when the amino acid supply increased. 7. It is concluded that: the small intestine is the main site of lactate production, and the peripheral tissues are the main site for lactate utilization; during increased ureogenesis in fed rats, lactate is poorly utilized by the liver; the gut is the main site of alanine production in rats fed on a high-carbohydrate diet and the liver utilizes most of the alanine introduced into the portal-vein plasma in both cases.

Download Full-text

Biochemical aspects of malabsorption in marasmus: effect of dietary rehabilitation

British Journal Of Nutrition ◽

10.1079/bjn19850143 ◽

1985 ◽

Vol 54 (3) ◽

pp. 567-575 ◽

Cited By ~ 3

Author(s):

H. C. Mehta ◽

A. S. Saini ◽

Harjit Singh ◽

P. S. Dhatt

Keyword(s):

Total Energy ◽

High Fat Diet ◽

High Protein Diet ◽

High Carbohydrate Diet ◽

High Protein ◽

Protein Diet ◽

Duodenal Juice ◽

High Fat ◽

Carbohydrate Diet ◽

High Carbohydrate

1. Sixty marasmic children were investigated for the absorption of xylose, proteins and fats. Their duodenal juice samples were also analysed for bile salts and microflora.2. The marasmic children were then studied in three groups of twenty by allocating them to three different dietary schedules: a high-protein diet (30% of the total energy from protein), a high-fat diet (40% of the total energy from fat) and a high-carbohydrate diet (70% of the total energy from carbohydrate) for 2 weeks and the previous measurements repeated.3. Whereas the high-fat diet resulted in improved fat absorption, along with an increase in total and conjugated bile acids, and the high-carbohydrate diet led to improved xylose absorption, the diet rich in protein resulted in an improvement in the absorption of all three dietary ingredients. It appears that a high-protein diet improves the overall absorption process by improving the intestinal environment as a whole, while high-carbohydrate and high-fat diets bring about adaptive changes related to the respective absorptive processes.

Download Full-text

Low-protein diet induces, whereas high-protein diet reduces hepatic FGF21 production in mice, but glucose and not amino acids up-regulate FGF21 in cultured hepatocytes

The Journal of Nutritional Biochemistry ◽

10.1016/j.jnutbio.2016.07.002 ◽

2016 ◽

Vol 36 ◽

pp. 60-67 ◽

Cited By ~ 18

Author(s):

Tristan Chalvon-Demersay ◽

Patrick C. Even ◽

Daniel Tomé ◽

Catherine Chaumontet ◽

Julien Piedcoq ◽

...

Keyword(s):

Amino Acids ◽

High Protein Diet ◽

High Protein ◽

Protein Diet ◽

Low Protein Diet ◽

Cultured Hepatocytes ◽

Low Protein

Download Full-text

Stearic Acid Supplementation in High Protein to Carbohydrate (P:C) Ratio Diet Improves Physiological and Mitochondrial Functions of Drosophila melanogaster parkin Null Mutants

The Journals of Gerontology Series A ◽

10.1093/gerona/glx246 ◽

2017 ◽

Vol 74 (10) ◽

pp. 1564-1572 ◽

Cited By ~ 6

Author(s):

Rijan Bajracharya ◽

Sonia Bustamante ◽

John William O Ballard

Keyword(s):

Fatty Acids ◽

Stearic Acid ◽

High Protein Diet ◽

High Carbohydrate Diet ◽

High Protein ◽

Protein Diet ◽

Carbohydrate Diet ◽

High Carbohydrate ◽

Mitochondrial Functions ◽

And Mitochondrial Functions

Abstract Optimizing dietary macronutrients benefits the prevention and management of many human diseases but there is conflicting dietary advice for Parkinson’s disease (PD), and no single strategy is universally recommended. Recently, it was shown that dietary stearic acid (C18:0) improves survival and mitochondrial functions in the parkin null Drosophila model of PD. Here, we incorporate stearic acid into high protein and high carbohydrate diets and study survival, climbing ability, mitochondrial membrane potential, respiration, basal reactive oxygen species, and conduct lipidomics assays. We observed that parkin null flies showed improvement in all assays tested when stearic acid was added to the high protein diet but not to the high carbohydrate diet. When lipid proportion was examined, we observed higher levels in flies fed the high protein diet with stearic acid diet and the high carbohydrate diet. Unexpectedly, free levels of fatty acids exhibited opposite trend. Combined, these data suggest that dietary Protein: Carbohydrate ratio and stearic acid influences levels of bound fatty acids. The mechanisms that influence free and bound fatty-acid levels remain to be explored, but one possible explanation is that breakdown products can bind to membranes and improve the mitochondrial functions of parkin null flies.

Download Full-text

Hypocaloric high-protein diet improves glucose oxidation and spares lean body mass: Comparison to hypocaloric high-carbohydrate diet

Metabolism ◽

10.1016/0026-0495(94)90005-1 ◽

1994 ◽

Vol 43 (12) ◽

pp. 1481-1487 ◽

Cited By ~ 142

Author(s):

P.M. Piatti ◽

L.D. Monti ◽

Fulvio Magni ◽

Isabella Fermo ◽

L. Baruffaldi ◽

...

Keyword(s):

Lean Body Mass ◽

Body Mass ◽

Glucose Oxidation ◽

High Protein Diet ◽

High Carbohydrate Diet ◽

High Protein ◽

Protein Diet ◽

Carbohydrate Diet ◽

High Carbohydrate ◽

Mass Comparison

Download Full-text

Splanchnic sequestration of amino acids in aged rats: in vivo and ex vivo experiments using a model of isolated perfused liver

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00291.2007 ◽

2008 ◽

Vol 294 (3) ◽

pp. R748-R755 ◽

Cited By ~ 16

Author(s):

M. Jourdan ◽

L. Cynober ◽

C. Moinard ◽

M. C. Blanc ◽

N. Neveux ◽

...

Keyword(s):

Amino Acids ◽

Ex Vivo ◽

High Protein Diet ◽

High Protein ◽

Protein Diet ◽

Aged Rats ◽

Sprague Dawley ◽

Adult Rats ◽

Urea Production

Splanchnic sequestration of amino acids (SSAA) is a process observed during aging that leads to decreased peripheral amino acid (AA) availability. The mechanisms underlying SSAA remain unknown. The aim of the present study was to determine whether a high-protein diet could increase nitrogen retention in aged rats by saturating SSAA and whether SSAA could be explained by dysregulation of hepatic nitrogen metabolism. Adult and aged male Sprague-Dawley rats were housed in individual metabolic cages and fed a normal-protein (17% protein) or high-protein diet (27%) for 2 wk. Nitrogen balance (NB) was calculated daily. On day 14, livers were isolated and perfused for 90 min to study AA and urea fluxes. NB was lower in aged rats fed a normal-protein diet than in adults, but a high-protein diet restored NB to adult levels. Isolated perfused livers from aged rats showed decreased urea production and arginine uptake, together with a release of alanine (vs. uptake in adult rats) and a hepatic accumulation of alanine. The in vivo data suggest that SSAA is a saturable process that responds to an increase in dietary protein content. The hepatic metabolism of AA in aged rats is greatly modified, and urea production decreases. This result refutes the hypothesis that SSAA is associated with an increase in AA disposal via urea production.

Download Full-text

Effect of the nature and amount of dietary energy on lipid composition of rat gingival tissue

British Journal Of Nutrition ◽

10.1079/bjn19830024 ◽

1983 ◽

Vol 49 (2) ◽

pp. 187-192

Author(s):

Salil K. Das ◽

Munalula L. Elliott ◽

Halifax C. King

Keyword(s):

Fatty Acid ◽

High Fat Diet ◽

High Protein Diet ◽

High Protein ◽

Protein Diet ◽

Gingival Tissue ◽

Dietary Energy ◽

High Fat ◽

High Carbohydrate ◽

Fat Diets

1. The effect of the nature and amount of dietary energy on the lipid composition of rat gingival tissue was studied. Male weanling rats were given one of three iso-energetic diets: high-carbohydrate, high-protein and extremely high-protein, or a fourth high-fat diet, for 49 d.2. The high-carbohydrate, extremely high-protein and high-fat diets caused significant increases in the gingival levels of total lipids compared with the normal-protein diet. These increases in total lipids were due primarily to increases in the levels of triglycerides and cholesterol esters. There were no significant differences in the fatty acid compositions of either non-polar or polar lipids among rats given the high-carbohydrate diet and those given the high-protein diet.3. A comparison of the fatty acid composition of lipids of rats given the extremely high-protein diet and the other two iso-energetic diets revealed that the proportion of palmitic acid was higher and the proportion of oleic acid was lower in animals given the extremely high-protein diet than in animals given the other two diets. Compared with the three iso-energetic low-fat diets, the high-fat diet caused decreases in the proportion of palmitic and palmitoleic acids and increases in the proportion of linoleic, arachidonic and docosapentaenoic acids in total fatty acids of both non-polar and polar lipids. It should be noted that the high-fat diet contained a high proportion of linoleic acid and it is expected that this diet would raise the 18:2 fatty acid content of the lipids and also would raise the 20:4 and 22:5 levels as 18:2 is an essential fatty acid and will, with its metabolites, be directly incorporated into tissue lipids.

Download Full-text

Fluxes and membrane transport of amino acids in rat liver under different protein diets

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1990.259.5.e614 ◽

1990 ◽

Vol 259 (5) ◽

pp. E614-E625 ◽

Cited By ~ 6

Author(s):

P. Fafournoux ◽

C. Remesy ◽

C. Demigne

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Aromatic Amino Acids ◽

High Protein Diet ◽

High Protein ◽

Protein Diet ◽

Transport Systems ◽

Low Concentrations ◽

Significant Uptake

The aim of the present work was to evaluate in vivo the role of the transport step in hepatic amino acid metabolism. To vary hepatic utilization of amino acids, rats were adapted to diets containing various concentrations of casein (5, 15, and 60%). In rats fed 5 or 15% casein diets, Gln and Glu were released by the liver, and there was a significant uptake of Ala. Hepatic fluxes of amino acids increased considerably after adaptation to high-casein diet (up to 1.55 mumol.min-1.g liver-1 for Ala), because of the rise in afferent concentrations as well as enhanced uptake percentage (peaking at 60–75% for most glucogenic amino acids). Adaptation to a high-protein diet led to induction of not only system A but also of most of the other transport systems (Gly, anionic, T, y+, and to a lesser extent system N); only systems ASC and L were unchanged. The study of amino acid repartition between liver and plasma with different diets indicates that transport could modulate utilization of Ala, Ser, Thr, Gly, Gln, and Asp. For Arg and Asn, present in very low concentrations in liver under any condition, the transport step should be the major locus of control of their metabolism. For amino acids chiefly transported by nonconcentrative systems, such as aromatic amino acids, cellular metabolism could also be limited by the transport process. In conclusion, during adaptation to a high-protein diet, there is apparently a coordinated adaptation of amino acid transport and of their intracellular metabolism. For some amino acids, induction of catabolic enzymes seems greater than that of transport, so that the transport step may play an important role in control of metabolic fluxes. For example, concentration of amino acids such as Thr may be markedly depressed in rats adapted to a high-protein diet.

Download Full-text

The effect of dietary composition and of insulin on gluconeogenesis in rainbow trout (Salmo gairdneri)

British Journal Of Nutrition ◽

10.1079/bjn19770103 ◽

1977 ◽

Vol 38 (3) ◽

pp. 385-395 ◽

Cited By ~ 108

Author(s):

C. B. Cowey ◽

M. De La Higuera ◽

J. W. Adron

Keyword(s):

Rainbow Trout ◽

High Protein Diet ◽

High Carbohydrate Diet ◽

High Protein ◽

Protein Diet ◽

Salmo Gairdneri ◽

Carbohydrate Diet ◽

Commercial Diet ◽

High Carbohydrate ◽

Gluconeogenesis From Alanine

1. The activities at 15° of three gluconeogenic enzymes, d-fructose-1,6-diphosphate, 1-phosphohydrolase (EC 3.1.3.11), pyruvate carboxylase (EC 6.4.1.1) and phosphoenolpyruvate carboxykinase (4.1.1.32), were determined in liver, kidney, gill and muscle of rainbow trout (Salmo gairdneri) given a commercial diet. The results indicated that liver and kidney are the main sites of gluconeogenesis.2. Glucose formation from pyruvate was approximately 6 μmol/h per g wet weight at 15° in liver slices of trout given a commercial diet.3. Glucose diffusion space in trout was measured by the dilution principle after intravascular injection of a trace dose of [U-14C]glucose. Glucose space was found to be 13.7% of the body-weight. Gluconeogenesis in vivo amounted to approximately 45 μmol/kg body-weight per h.4. Intraperitoneally injected [U-14C]alanine was quickly converted to glucose. Maximal incorporation of alanine into glucose occurred 6 h after alanine administration.5. Rainbow trout given a high-protein diet gained in weight significantly during a 4-week period. Those given a high-carbohydrate diet did not make a significant weight gain over the same period. Gluconeogenesis from alanine was markedly reduced in fish given the high-carbohydrate diet. There was no significant difference in gluconeogenesis from alanine in fish given a high-protein diet and fish which were fasted for 21 d.6. Gluconeogenesis from alanine in trout was suppressed by intravenous injection of insulin. This effect was found both in trout given a high-protein diet and in fasted trout.

Download Full-text