Plasma cholecystokinin and pancreatic growth during adaptation to dietary protein

1986 ◽  
Vol 251 (1) ◽  
pp. G70-G74 ◽  
Author(s):  
G. M. Green ◽  
V. H. Levan ◽  
R. A. Liddle
Keyword(s):  
Food Intake ◽  
Control Diet ◽  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Pancreatic Acini ◽  
Pancreatic Growth ◽  
Low Protein ◽  
Plasma Cholecystokinin ◽  
Pancreatic Protease

The relationship among plasma cholecystokinin (CCK), pancreatic growth, and food intake was studied in rats over a 2-wk period of adaptation from a very low-protein to a very high-protein diet. Rats adapted to a control diet (5% casein) were killed at 0900 (without fasting) at 0 h, 12 h, 24 h, 48 h, 7 days, or 14 days after transfer to a high-protein diet (75% casein). CCK was measured by bioassay using isolated pancreatic acini. Plasma CCK in high protein-fed rats was increased approximately threefold in the first 24 h, but returned to control (approximately 2.5 pM) values by day 7. Pancreatic weight, DNA, protein, and chymotrypsin(ogen) significantly increased to maximal values by day 7 in high protein-fed rats. Food intake in high protein-fed rats was inhibited by 47% after 24 h but returned to control values by day 7. The results indicate that high-protein diets initially increase CCK release and increase pancreatic protease secretory capacity and that, when pancreatic protease secretion is sufficient to match protein digestive requirements, the stimulus for CCK secretion is reduced and plasma CCK returns to normal. The pronounced but transient inhibition of food intake in high protein-fed rats is consistent with a role for CCK in regulation of food intake.

Food and protein intake, glucagon, and distribution of alpha-aminoisobutyrate in the rat

1980 ◽  
Vol 238 (4) ◽  
pp. E358-E363
Author(s):  
J. K. Tews ◽  
A. E. Harper
Keyword(s):  
Dietary Protein ◽  
Protein Intake ◽  
Control Diet ◽  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Tissue Water ◽  
Low Protein ◽  
Protein Diets ◽  
Different Tissues

Distribution of alpha-aminoisobutyric acid (AIB) in the rat was modified by food, dietary protein, and glucagon. In rats last fed 24 h before AIB injection, AIB clearance from plasma and uptake into liver were greater in rats fed a high-protein diet (60% casein) than in rats fed the control diet (18% casein); AIB clearance from plasma and uptake into muscle were lowered by a low-protein diet (6% casein). Feeding rats lowered clearance of AIB from plasma in low- and high-protein groups. Distribution ratios (AIB concentration in tissue water/AIB in plasma) were low in all tissues but liver during the first 7 h after feeding high protein when compared to the control values; ratios were low in muscle, heart, and kidney after feeding low protein. Maximum ratios occurred at different times for different tissues; the time was delayed by the high-protein diet in all tissues but liver. Glucagon increased all ratios in rats fed the control or low-protein diets, with the smallest changes occurring in liver and muscle from low-protein rats.

scholarly journals Adaptive changes in the capacity of systems used for the synthesis of citrulline in rat liver mitochondria in response to high- and low-protein diets

1974 ◽  
Vol 142 (2) ◽  
pp. 359-364 ◽  
Author(s):  
J. D. McGivan ◽  
Norah M. Bradford ◽  
J. B. Chappell
Keyword(s):  
Nitrogen Source ◽  
High Protein Diet ◽  
Liver Mitochondria ◽  
High Protein ◽  
Protein Diet ◽  
Rat Liver Mitochondria ◽  
Standard Diet ◽  
Adaptive Changes ◽  
Low Protein ◽  
Citrulline Synthesis

1. Citrulline synthesis was measured in mitochondria from rats fed on a standard diet, a high-protein diet, or on glucose. 2. With NH4Cl as the nitrogen source the rate of citrulline synthesis was higher in mitochondria from rats fed on a high-protein diet than in those from rats fed on a standard diet. When rats were fed solely on glucose the rate of synthesis of citrulline from NH4Cl was very low. 3. With glutamate as the nitrogen source the relative rates of citrulline synthesis were much lower than when NH4Cl was present, but similar adaptive changes occurred. 4. The activity of the mitochondrial glutamate-transporting system increased two to three times on feeding rats on a high-protein diet, but the Km for glutamate was unchanged. 5. Adaptive changes in certain intramitochondrial enzymes were also measured. 6. The results were interpreted to indicate that when an excess of substrate was present, citrulline synthesis from NH4Cl was rate-limited by the intramitochondrial concentration of N-acetyl-glutamate, but citrulline synthesis from glutamate was rate-limited primarily by the activity of the glutamate-transporting system.

scholarly journals High‐protein diet more effectively reduces hepatic fat than low‐protein diet despite lower autophagy and FGF21 levels

2020 ◽  
Vol 40 (12) ◽  
pp. 2982-2997 ◽  
Author(s):  
Chenchen Xu ◽  
Mariya Markova ◽  
Nicole Seebeck ◽  
Anne Loft ◽  
Silke Hornemann ◽  
...  
Keyword(s):  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Low Protein ◽  
Hepatic Fat

Digestion by sheep of concentrate diets containing formaldehyde-treated peanut meal

1972 ◽  
Vol 23 (5) ◽  
pp. 859 ◽  
Author(s):  
GJ Faichney
Keyword(s):  
Organic Matter ◽  
Peanut Meal ◽  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Plasma Urea ◽  
Protein Levels ◽  
Low Protein ◽  
Formaldehyde Treatment ◽  
Protein Diets

The effect of formaldehyde treatment of peanut meal on the digestion of barley-peanut meal diets was studied in fistulated crossbred sheep at two peanut meal and therefore dietary protein levels. There were no differences either between protein levels or due to treatment in the overall digestion of organic matter, but more of this digestion took place in the stomach when the low protein diets were given. Dietary starch was completely digested. There was no effect of protein level or of formaldehyde treatment on the partition of starch digestion between the stomach and the intestines. About 10% of the dietary nitrogen disappeared from the stomach when the high protein diet containing untreated peanut meal was given; treatment resulted in a small net gain of nitrogen in the stomach. There was a net gain of nitrogen in the stomach when the low protein diets were given, the gain tending to be greater when the peanut meal was treated. When the meal was treated, there was a small but not significant increase (c. 2%) for the low protein diet and a substantial increase (c. 31 %) for the high protein diet in the amount of crude protein digested in the intestines per unit of digestible organic matter intake. Changes observed in the composition and flow of digesta and in plasma urea and cc-amino nitrogen levels are discussed in relation to the digestion of organic matter and protein.

scholarly journals The Intestinal Peptide Transporter PEPT1 Is Involved in Food Intake Regulation in Mice Fed a High-Protein Diet

PLoS ONE ◽  
2011 ◽  
Vol 6 (10) ◽  
pp. e26407 ◽  
Author(s):  
Anna-Maria Nässl ◽  
Isabel Rubio-Aliaga ◽  
Manuela Sailer ◽  
Hannelore Daniel
Keyword(s):  
Food Intake ◽  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Peptide Transporter ◽  
Food Intake Regulation ◽  
Intake Regulation

scholarly journals An isoenergetic high-protein, moderate-fat diet does not compromise strength and fatigue during resistance exercise in women

2008 ◽  
Vol 100 (2) ◽  
pp. 283-286 ◽  
Author(s):  
Konstantina Dipla ◽  
Maria Makri ◽  
Andreas Zafeiridis ◽  
Dimitrios Soulas ◽  
Sofia Tsalouhidou ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Lower Limb ◽  
High Intensity ◽  
Handgrip Strength ◽  
Control Diet ◽  
High Protein Diet ◽  
High Protein ◽  
Lower Limbs ◽  
Protein Diet ◽  
Isometric Handgrip

Resistance exercise is recommended to individuals following high-protein diets in order to augment changes in body composition. However, alterations in macronutrient composition may compromise physical performance. The present study investigated the effects of an isoenergetic high-protein diet on upper and lower limb strength and fatigue during high-intensity resistance exercise. Ten recreationally active women, aged 25–40 years, followed a control diet (55, 15 and 30 % of energy from carbohydrate, protein and fat, respectively) and a high-protein diet (respective values, 30, 40 and 30) for 7 d each in a random counterbalanced design. Each participant underwent strength testing of upper limb (isometric handgrip strength and endurance) and lower limb (four sets of sixteen maximal knee flexions and extensions on an isokinetic dynamometer) before and after applying each diet. Body weight, body fat and RER were significantly reduced following the high-protein diet (P < 0·05). No differences were found between diets in any of the strength performance parameters (handgrip strength, handgrip endurance, peak torque, total work and fatigue) or the responses of heart rate, systolic and diastolic arterial pressure, blood lactate and blood glucose to exercise. Women on a short-term isoenergetic high-protein, moderate-fat diet maintained muscular strength and endurance of upper and lower limbs during high-intensity resistance exercise without experiencing fatigue earlier compared with a control diet.

scholarly journals Post-Copulatory Female Choice in Sagebrush Crickets

1996 ◽  
Vol 20 ◽  
pp. 57-62
Author(s):  
J. Johnson ◽  
Tracie Ivy ◽  
Anne-Katrin Eggert ◽  
Scott Sakaluk
Keyword(s):  
Female Choice ◽  
Nutrient Intake ◽  
High Protein Diet ◽  
Copulatory Behavior ◽  
Egg Laying ◽  
High Protein ◽  
Protein Diet ◽  
Mating Status ◽  
Low Protein ◽  
Cyphoderris Strepitans

Male sagebrush crickets (Cyphoderris strepitans) permit females to engage in an unusual form of sexual cannibalism during copulation: females feed on males' fleshy hind wings and ingest haemolymph oozing from the wounds they inflict. These wounds are not fatal, and normally only a portion of the hind wings are eaten at any one mating, so that mated males are not precluded from mating again. However, non-virgin males have fewer resources to offer females than do virgin males, such that females should be selected to preferentially mate with virgin males. Because previous work has indicated a lack of pre-copulatory female choice, we tested the hypothesis that females accept matings with non-virgin males, but discriminate against them afterwards by re-mating sooner than they otherwise would after matings with virgin males. If the last male to copulate with a female prior to egg laying does in fact sire the majority of her offspring, then such post-copulatory behavior would constitute a form of female choice. To test this, we experimentally manipulated both female diet (high protein vs. low protein), and the female's ability to feed on males' wings during mating. We predicted that females prevented from wing feeding and held on a low protein diet would remate sooner than females allowed to wing feed and held on a high protein diet. We measured the amount of time males spent calling in mating trials, and the time to first and second mountings and matings for each female. Our results reveal an effect of wing treatment on the time to first mating. Low protein females mated with winged males significantly more readily than they did with de­winged males. Female diet also had a significant effect on the time to first mounting. Females fed only lettuce (low protein) mounted males sooner than females provisioned with apple and a bee pollen supplement (high protein), indicating that a female's overall nutrient intake may determine her propensity to mate regardless of the mating status of the male she is paired with. No effect of diet or wing treatment was found for time to second mounting or mating.

scholarly journals Liver GCN2 controls hepatic FGF21 secretion and modulates whole body postprandial oxidation profile under a low-protein diet

2019 ◽  
Vol 317 (6) ◽  
pp. E1015-E1021 ◽  
Author(s):  
Tristan Chalvon-Demersay ◽  
Joanna Moro ◽  
Patrick C. Even ◽  
Catherine Chaumontet ◽  
Daniel Tomé ◽  
...  
Keyword(s):  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Whole Body ◽  
Low Protein ◽  
The One ◽  
High Level ◽  
High Protein Diets

General control nonderepressible 2 (GCN2) is a kinase that detects amino acid deficiency and is involved in the control of protein synthesis and energy metabolism. However, the role of hepatic GCN2 in the metabolic adaptations in response to the modulation of dietary protein has been seldom studied. Wild-type (WT) and liver GCN2-deficient (KO) mice were fed either a normo-protein diet, a low-protein diet, or a high-protein diet for 3 wk. During this period, body weight, food intake, and metabolic parameters were followed. In mice fed normo- and high-protein diets, GCN2 pathway in the liver is not activated in WT mice, leading to a similar metabolic profile with the one of KO mice. On the contrary, a low-protein diet activates GCN2 in WT mice, inducing FGF21 secretion. In turn, FGF21 maintains a high level of lipid oxidation, leading to a different postprandial oxidation profile compared with KO mice. Hepatic GCN2 controls FGF21 secretion under a low-protein diet and modulates a whole body postprandial oxidation profile.

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