Serotonin and feeding responses of rats to amino acid imbalance: initial phase

1987 ◽  
Vol 253 (5) ◽  
pp. R763-R771 ◽  
Author(s):  
D. W. Gietzen ◽  
Q. R. Rogers ◽  
P. M. Leung ◽  
B. Semon ◽  
T. Piechota
Keyword(s):  
Amino Acid ◽  
Food Intake ◽  
Acid Diet ◽  
Serotonergic Activity ◽  
Amino Acid Imbalance ◽  
Serotonin Turnover ◽  
Initial Depression ◽  
Diet Intake ◽  
Made In

The role of serotonin in the anorexic response of rats to an amino acid-imbalanced diet was investigated. After chronic depletion of serotonin with parachlorophenylalanine (PCPA, 300 mg/kg) or 5,7-dihydroxytryptamine (DHT, 200 micrograms/rat, intracisternally), initial intake of a mild isoleucine-imbalanced diet was reduced by 60% vs. a 17% reduction after saline injection. After acute treatment with the agonist, quipazine (quip, 5 mg/kg ip) or the precursor, tryptophan (TRP, 1% added to the diet), imbalanced diet intake was also exacerbated. PCPA and DHT may have caused receptor supersensitivity, such that the food intake depression after serotonin depletion was similar to that seen with the quip and TRP treatments. Injection of the autoreceptor agonist, 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT, 500 micrograms/kg sc), to reduce transmission in the serotonergic systems resulted in an attenuation of the usual food intake depression of the amino acid-imbalanced diet (only a 7%, nonsignificant reduction). Also measurements made in the absence of pharmacological treatment showed that the ratio 5-hydroxyindole acetic acid-to-serotonin, a putative index of serotonin turnover, was increased 155% in the raphe nuclei and 140% in the hippocampus 3.5 h after ingestion of the mild isoleucine-imbalanced diet. Therefore increased serotonergic activity in some brain areas may be associated with the initial depression of food intake in rats fed an imbalanced amino acid diet.

Anorectic responses to dietary amino acid imbalance: effects of vagotomy and tropisetron

1994 ◽  
Vol 266 (6) ◽  
pp. R1922-R1927 ◽  
Author(s):  
B. S. Washburn ◽  
J. C. Jiang ◽  
S. L. Cummings ◽  
K. Dixon ◽  
D. W. Gietzen
Keyword(s):  
Amino Acid ◽  
Food Intake ◽  
Treated Group ◽  
Amino Acid Deficiency ◽  
Full Effect ◽  
Acid Deficiency ◽  
Dietary Amino Acid ◽  
Amino Acid Imbalance ◽  
Diet Intake ◽  
Vagal Function

We investigated the roles of the vagus nerve and the serotonin3 (5-HT3) receptor in mediating the food intake depression associated with amino acid deficiency. The food intake of sham-operated (sham) rats given an isoleucine-imbalanced (IMB) diet was reduced to < 40% of control basal (BAS) diet intake (P = 0.0009), and pretreatment with the 5-HT3 antagonist tropisetron (Trop) increased IMB intake by twofold over the vehicle (VEH)-treated group (P < or = 0.0001), as we have reported before. However, after subdiaphragmatic vagotomy (VAGX), IMB intake was increased to a level intermediate between the sham-VEH and sham-Trop groups, while administration of Trop did not increase IMB intake over VAGX alone. By the end of day 1, the VAGX-Trop group had eaten only 1 g more of IMB than the VAGX-VEH group (NS). We conclude that 1) the vagus is among the physiological systems involved in the anorectic responses to IMB and 2) intact vagal function is necessary for the full effect of 5-HT3 antagonists in alleviating the anorectic responses to IMB.

scholarly journals Biological role of the general control of amino acid biosynthesis in Saccharomyces cerevisiae.

1981 ◽  
Vol 1 (7) ◽  
pp. 584-593 ◽  
Author(s):  
P Niederberger ◽  
G Miozzari ◽  
R Hütter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Amino Acid Biosynthesis ◽  
Wild Type ◽  
General Control ◽  
Acid Biosynthesis ◽  
Mutant Strains ◽  
In The Wild ◽  
Amino Acid Imbalance

The biological role of the "general control of amino acid biosynthesis" has been investigated by analyzing growth and enzyme levels in wild-type, bradytrophic, and nonderepressing mutant strains of Saccharomyces cerevisiae. Amino acid limitation was achieved by using either bradytrophic mutations or external amino acid imbalance. In the wild-type strain noncoordinate derepression of enzymes subject to the general control has been found. Derepressing factors were in the order of 2 to 4 in bradytrophic mutant strains grown under limiting conditions and only in the order of 1.5 to 2 under the influence of external amino acid imbalance. Nonderepressing mutations led to slower growth rates under conditions of amino acid limitation, and no derepression of enzymes under the general control was observed. The amino acid pools were found to be very similar in the wild type and in nonderepressing mutant strains under all conditions tested. Our results indicate that the general control affects all branched amino acid biosynthetic pathways, namely, those of the aromatic amino acids and the aspartate family, the pathways for the basic amino acids lysine, histidine, and arginine, and also the pathways of serine and valine biosyntheses.

scholarly journals Effects of essential amino acids on food and water intake of rats

1994 ◽  
Vol 72 (8) ◽  
pp. 841-848 ◽  
Author(s):  
G. Harvey Anderson ◽  
Shuqin Luo ◽  
Leonidas Trigazis ◽  
Greta Kubis ◽  
Edmund T. S. Li
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Food Intake ◽  
Water Intake ◽  
Essential Amino Acids ◽  
Time Period ◽  
Food And Water Intake ◽  
Intake Water ◽  
Comparable Magnitude

This study examined the effects of selected groups of essential amino acids (EAAs), given by gavage, on short-term food and water intake. Amino acid groups were selected on the basis of their common physiologic functions in relation to current hypotheses on the role of amino acids in food intake control, and the quantities given were based on the proportions in 1.5 g of the EAA content of albumin. The complete EAA mixture (1.5 g) suppressed food intake by an average of 60 and 37% during the 1st and 2nd h of feeding, respectively, but had no influence on feeding in the subsequent 12 h. Total daily (14 h) intake was decreased by 9%. With the exception of the aromatic amino acid (Phe + Tyr + Trp, 0.34 g) group, all groups significantly decreased food intake by a comparable magnitude (32%) during the 1st h. In this time period, rats given the EAAs, Arg + Met + Val (0.38 g), and Arg + His + Lys (0.44 g) mixtures increased their water intake, whereas intake by rats given the Phe + Tyr + Trp + Thr (0.46 g) and Ile + Leu + Val (0.45 g) mixtures was unchanged. Thus, the food intake suppression caused by EAAs was not accounted for by an equal effect of its component amino acid groups. As well, food intake suppression by amino acid groups was not explained by increased water consumption, nor was it simply related to the quantity of nitrogen provided by the treatment.Key words: food intake, water intake, essential amino acids.

Effect of amino acid imbalance on food intake and preference

1962 ◽  
Vol 202 (1) ◽  
pp. 165-170 ◽  
Author(s):  
Juan C. Sanahuja ◽  
Alfred E. Harper
Keyword(s):  
Amino Acid ◽  
Food Intake ◽  
Food Preference ◽  
Food Selection ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Balanced Diet ◽  
Amino Acid Imbalance ◽  
Ad Libitum ◽  
Protein Free Diet

Effects of an amino acid imbalance, caused by adding 3.8% of an amino acid mixture lacking histidine to a diet containing 6% of beef fibrin, on the food intake and food preference of protein-depleted rats are described. After being depleted, animals fed the balanced or imbalanced diets ate equal amounts for 3 days, then both growth rate and food intake of those fed the imbalanced diet dropped. When protein-depleted rats were fed the balanced or imbalanced diet together with a protein-free diet, neither group ate the protein-free diet during the first 3 days. Thereafter, animals fed the imbalanced diet began to eat the protein-free diet in preference to the imbalanced diet, even though the latter would support growth and the former would not. Animals fed ad libitum the balanced diet or the imbalanced diet plus histidine did not eat the protein-free diet at all. These observations indicate that both food intake and food selection are influenced by the amino acid pattern of the diet.

Amino Acid Imbalance and Diet Preference in the Hypothalamic–Hyperphagic Rat

1971 ◽  
Vol 49 (8) ◽  
pp. 752-757 ◽  
Author(s):  
S. M. Arakawa ◽  
B. R. Standal ◽  
J. R. Beaton
Keyword(s):  
Amino Acid ◽  
Food Intake ◽  
Diet Selection ◽  
Amino Acid Pattern ◽  
Plasma Amino Acid ◽  
Diet Preference ◽  
Amino Acid Imbalance ◽  
Satiety Center

Diet selection by control and hypothalamic–hyperphagic rats was recorded to examine the hypothesis that the plasma amino acid pattern may act as a satiety signal with respect to the decreased food intake associated with amino acid unbalanced diets. Rats were offered choices between: (a) protein-free and imbalanced diets; (b) imbalanced and corrected diets; (c) corrected and basal diets. Although selection by control and operated rats differed with respect to choice a, selection behaviors were comparable for choices b and c. Plasma amino acid patterns were similar in control and operated rats indicating that the same potential satiety signal was present in both groups. Since the "satiety center" was ablated in operated rats, it would seem that if plasma amino acid patterns serve as a satiety signal, this signal must act in some manner other than on the ventromedial area of the hypothalamus.

scholarly journals Low-arginine and low-protein diets induce hepatic lipid accumulation through different mechanisms in growing rats

2020 ◽  
Author(s):  
Lila Otani ◽  
Hiroki Nishi ◽  
Ayaka Koyama ◽  
Yuta Akasaka ◽  
Yusuke Taguchi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Fatty Liver ◽  
Wistar Rats ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Total Amino Acid ◽  
Acid Diet ◽  
Hepatic Fat ◽  
Amino Acid Imbalance ◽  
Amino Acid Diet

Abstract Background Dietary protein deficiency and amino acid imbalance cause hepatic fat accumulation. We previously demonstrated that only arginine deficiency or total amino acid deficiency in a diet caused significant hepatic triglyceride (TG) accumulation in young Wistar rats. In this study, we explored the mechanisms of fatty liver formation in these models.Dietary protein deficiency and amino acid imbalance cause hepatic fat accumulation. We previously demonstrated that only arginine deficiency or total amino acid deficiency in a diet caused significant hepatic triglyceride (TG) accumulation in young Wistar rats. In this study, we explored the mechanisms of fatty liver formation in these models. Methods We fed 6-week-old male Wistar rats a control diet (containing an amino acid mixture equivalent to 15% protein), a low-total-amino acid diet (equivalent to 5% protein; 5PAA), and a low-arginine diet (only the arginine content is as low as that of the 5PAA diet) for 2 weeks. Results Much greater hepatic TG accumulation was observed in the low-arginine group than in the low-total-amino acid group. The lipid consumption rate and fatty acid uptake in the liver did not significantly differ between the groups. In contrast, the low-total-amino acid diet potentiated insulin sensitivity and related signaling in the liver and enhanced de novo lipogenesis. The low-arginine diet also inhibited hepatic very-low-density lipoprotein secretion without affecting hepatic insulin signaling and lipogenesis. Conclusions : Although the arginine content of the low-arginine diet was as low as that of the low-total-amino acid diet, the two diets caused fatty liver via completely different mechanisms. Enhanced lipogenesis was the primary cause of a low-protein diet-induced fatty liver, whereas lower very-low-density lipoprotein secretion caused low-arginine diet-induced fatty liver.

Biological role of the general control of amino acid biosynthesis in Saccharomyces cerevisiae

1981 ◽  
Vol 1 (7) ◽  
pp. 584-593
Author(s):  
P Niederberger ◽  
G Miozzari ◽  
R Hütter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Amino Acid Biosynthesis ◽  
Wild Type ◽  
General Control ◽  
Acid Biosynthesis ◽  
Mutant Strains ◽  
In The Wild ◽  
Amino Acid Imbalance

The biological role of the "general control of amino acid biosynthesis" has been investigated by analyzing growth and enzyme levels in wild-type, bradytrophic, and nonderepressing mutant strains of Saccharomyces cerevisiae. Amino acid limitation was achieved by using either bradytrophic mutations or external amino acid imbalance. In the wild-type strain noncoordinate derepression of enzymes subject to the general control has been found. Derepressing factors were in the order of 2 to 4 in bradytrophic mutant strains grown under limiting conditions and only in the order of 1.5 to 2 under the influence of external amino acid imbalance. Nonderepressing mutations led to slower growth rates under conditions of amino acid limitation, and no derepression of enzymes under the general control was observed. The amino acid pools were found to be very similar in the wild type and in nonderepressing mutant strains under all conditions tested. Our results indicate that the general control affects all branched amino acid biosynthetic pathways, namely, those of the aromatic amino acids and the aspartate family, the pathways for the basic amino acids lysine, histidine, and arginine, and also the pathways of serine and valine biosyntheses.

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