Partial Food Deprivation Research Articles

Reestablishment of ad libitum feeding following partial food deprivation: Impact on locomotor activity, visceral fat, food intake, and circadian glycemic curve

ABSTRACT Food deprivation has been associated with the development of metabolic pathologies. Few studies have explored the repercussions of a partial food deprivation following the reestablishment of an ad libitum diet. This study investigates the impact of a partial food deprivation (an 8-hour food intake restriction coupled with a 4-hour feeding window during the active phase) and the subsequent return to ad libitum feeding on the glycemic curve, food intake, and locomotor behavior. Wistar rats aged 45 days were subjected to 6 weeks of a partial food deprivation followed by 6 weeks of ad libitum feeding. Body weight, visceral fat, food intake, circadian glycemia, oral glucose tolerance, and locomotor activity were evaluated. It was found that the partial food deprivation resulted in the reduction of both the body weight and food intake; however, it increased visceral fat by 60%. Circadian glycemic values were altered at all intervals during the light phase, and glucose sensitivity improved at 60 minutes in the oral glucose tolerance test (OGTT). In the food-deprived group, the locomotor activity rhythm was reduced, with an observed delay in the peak of activity, reduction in total activity, and a decrease in the rhythmicity percentage. After the reestablishment of the ad libitum feeding, there was recovery of body weight, no difference in visceral fat, normalization of the food intake pattern, circadian glycemia, and oral glucose tolerance. Additionally, the return to ad libitum feeding restored locomotor activity, although the duration required for its complete recovery warrants further investigation. In conclusion, partial food deprivation induces physio-metabolic changes in rats, most of which are reversed after reestablishing ad libitum feeding.

Experimental study of cognitive function against the background of partial food derivation and its correction

Tumors of the head and neck account for a significant percentage of all oncopathology. Oral cancer is most often diagnosed. The location of the tumor and its invasion causes swallowing disorders in the preoperative period, which is exacerbated in the postoperative period due to bulky defects. Impaired swallowing leads to reduced nutritional status. Of interest is cognitive function against the background of nutritional deficiency. Metabolic disorders such as obesity are known to adversely affect cognitive function and may even lead to dementia. But it is still unknown how food deprivation affects the cognitive function of rats, as well as the ability of animals to cope with stressful situations, because hunger is one of the models of stressors. Objective – to assess the state of cognitive function and stress resistance against the background of partial food deprivation and its correction in the experiment. The work was performed on 60 adult male rats weighing 280±20 g (M±m) of the Wistar line. Prior to the experimental study, the animals were on partial food deprivation (PFD). After weight loss, rats were divided into 4 groups depending on the dietary adjustment schemes: 1 group - control animals, nutrition according to physiological needs; Group 2, partial food derivation (PFD), without compensatory nutrition; Group 3 – compensatory enteral nutrition with food mixture "Peptamen" (PFD+EX); Group 4 – enteral nutrition and the drug Glutargin (PFD+EX+Glutargin). Behavioral response and cognitive function were determined in the open field test and in the CRPA model (conditioned reflex of passive avoidance). Our results show that rats with partial food deprivation are more prone to stress and can not find a sure way out of this situation. Also, throughout the study period, they suffered from cognitive function, as evidenced by the CRPA test data. In the study of resistance to stress on the background of partial food derivation, rats that continued to receive a limited diet by indicators (ambulation, grooming, rearing. defecation) were not stress-resistant, compared with the control group on the background of compensatory nutrition (p<0.05). During all periods of the study of cognitive function there was a change in the rate of stay in the light chamber with a significant (p<0.05) improvement in group 1 – 20.5%, group 3 – 18.36% and group 4 – 19.53%.

Study of the effect of arginine glutamate on cognitive processes in food-deprived rats

Annotation. In 2022, due to the COVID-19 pandemic and the aggravation of the food crisis, as a result of the full-scale Russian invasion of Ukraine, the share of the world's starving population has increased to 9.8% of the world's population. According to the literature, metabolic and neuroendocrine disorders during starvation have a negative impact on cognitive processes and social behavior. The aim of the study was to justify experimentally the feasibility of using glutargin for the correction of cognitive disorders in rats with partial food deprivation. The work includes such research methods as modeling of food deprivation according to the patented method, assessment of behavioral reactions and emotional state of rats using the "Open field" method, and study of working memory functions by the method of recognizing new objects. Statistical processing of the obtained results was carried out using non-parametric methods of analysis (MANOVA-test) using Statistica 6.0 software. Differences at p < 0.05 were considered significant. Partial food deprivation led to a decrease in the body weight of rats (about 30%, p<0.05), and an increase in the level of anxiety, which is evidenced by an increase in the average indicators of grooming by 53.7% and the average value of vertical activity by almost three times compared to the control group, a decrease in horizontal activity by 64.07%, which may be the result of a decrease in research activity and a decrease in interest to the environment. In contrast, in rats treated with glutargin, scores of anxiety were almost constant throughout the experiment. The test of recognition of new objects conducted at the end of the treatment shows that glutargin statistically significantly increased the coefficient of discrimination (CD), which indicated the restoration of nonspatial memory disorders that occurred in rats with experimental food deprivation. The obtained results are an experimental basis for further clinical studies devoted to the possibility of the practical use of glutargin in the complex treatment of patients with nutritional deficiency.

Experimental evaluation of the effect of supplementary nutrition and glutargine on regenerative properties

The problem of alimentary dystrophy, which develops due to various reasons, is an urgent problem, especially in patients with tumors of the head and neck. After removal of tumors, patients have large postoperative defects that interfere with proper nutrition. Therefore, to provide the body with the necessary nutrients, enteral nutrition is especially important. In addition, successful wound healing requires adequate blood supply and sufficient levels of nutrients, which depends on the general condition of the body and the patient's diet. However, the degree of reparative processes correlates not only with the number of substrates of anabolism, but also with the proper functioning of the liver. The aim of our study was to investigate the effect of the drug for enteral nutrition and glutargin on the reparative properties of rats’ wounds on the background of partial food deprivation. The study was performed on 60 adult male rats weighing 280±20 grams of the Wistar line, with a mean age of 15 weeks. Prior to the experimental study the regenerative properties of the animals were on partial food deprivation. On the 10th day, a wound with a diameter of 2.0 cm was inflicted. Then the rats were divided into 4 groups: 1 group (control) received food according to physiological needs; Group 2 (food derivation (FD)); Group 3 (FD+enteral nutrition); Group 4 (FD+enteral nutrition +glutargin). Against the background of alimentary dystrophy (20% weight loss) on the first day there was a significant difference in the edges of the wound due to loss of its elasticity. Wound contraction processes up to 14-15 days in all observation groups were quite active, regardless of the factors of malnutrition with cereals or additional therapeutic diet "Peptamen" or in combination with glutargin. Thus, every three days the area of wounds decreased by 30-40 mm2 on an average. Only on the 15th-17th day the difference in the rate of wound contraction becomes visible and statistically significant. Thus, on the 15th day the largest wounds were in the second group on the background of partial food deprivation (p<0.05), at the same time in the first (control) and in the fourth groups the average area was almost equal (p>0.05). The smallest (p<0.05) area of wounds was observed in the first group (control) on the 15th day. On the 17th day wound healing was observed in the fourth group (FD+enteral nutrition+glutargin), despite the expansion of wounds on the first day. A pronounced therapeutic effect correcting alimentary dystrophy was obtained with enteral nutrition (Peptamen) and glutargin at a dose of 50 mg/kg, where the wounds healed simultaneously with those in the first (control) group, ie in animals with a normal diet, indicating a high effectiveness of the proposed method of correction of alimentary dystrophy. Enteral nutrition alone (Peptamen) was also effective, as evidenced by the small size of virtually epithelialized wounds on the 17th day.

EFFECT OF ENTERAL NUTRITION IN COMBINATION WITH L-ARGININE AND GLUTAMIC ACID ON NUTRITIONAL STATUS IN EXPERIMENT

The aim of the study is to evaluate the scheme of complex therapy based on enteral nutrition and L-arginine, glutamic acid on the indicators of protein, carbohydrate, and lipid metabolism in the blood of rats with experimental wound defects of the skin under conditions of partial food deprivation.
 Materials and methods. A biochemical study of blood was carried out in 24 sexually mature male rats, which were partially food deprived for 10 days. On the 10th day, a wound was made and the animals were divided into 4 groups: the 1st group of control animals, which received food according to physiological needs; the 2nd group, which continued to be partially food deprived; and the 3rd group of rats, which after being exposed to dystrophy modelling for 10 days, were given compensatory enteral nutrition; the 4th group, which after the food deprivation, received L-arginine and glutamic acid in a dose of 50 mg/kg in addition to enteral nutrition. Blood sampling was carried out by removing the animals from the experiment on the 28th day. The following biochemical indicators were studied: the content of glucose, total protein, albumins, urea, the level of non-esterified fatty acids (NFA), ketone bodies, ammonia and TBC-reactants.
 Results. Comparative analysis of glucose content showed that integrative therapy prevented the development of hypoglycemia under the conditions of partial food derivation (р˂0.05). The positive effect of the combined action of enteral nutrition and L-arginine, glutamic acid on the serum content of total protein was found to be higher by 18% (р˂0.05), and albumin by 39% (р˂0.05), urea and ammonia was by 50% and 40.1% smaller (р˂0.05), NEJK was lower by 32.4% (р˂0.05), the content of ketone bodies was lower by 73.2% (р˂0.05), and TBK- reactants was lower by 50.4% (р˂0.05), compared to the untreated animals, and these indicators did not statistically significantly differ from the control values.
 Conclusion. The integrated therapy based on enteral nutrition and L-arginine, glutamic acid under the partial food deprivation effectively normalized protein metabolism, indicators of lipid and nitrogen metabolism in the body of rats (p˂0.05), relative to untreated animals.

Дослідження впливу аргініну глутамату на репаративні процеси у щурів з харчовою депривацією

The purpose of the study was to experimentally substantiate the feasibility of arginine glutamate using, for the correction of reparative disorders in rats with partial food deprivation. Materials and methods. The work uses such research methods as modeling of food deprivation according to a patented method, modeling a wound defect of rat’s skin, evaluating the healing of wound defects by taking pictures with a camera with a resolution of 12 megapixels and subsequent processing with a special computer program Universal desktop ruler, version 11, for determining the area, determination of integral indicators of total protein, albumin, glucose, urea in blood serum of rats by spectrophotometric methods (“Filicit-diagnostics”). Statistical processing of the obtained results was carried out using non-parametric methods of analysis (MANOVA-test) using Statistica 6.0 software. Differences at p<0.05 were considered significant. Results and discussion. As a result of the food crisis, the share of hungry people in the world increases every year, and in 2022 it reached 9.8% of the world population. Starvation directly and indirectly prevents the successful healing of wounds, which is also complicated by impaired liver function. Partial food deprivation was accompanied by a violation of metabolic processes in the body of rats: a decrease in body weight (about 30%, p<0.05), a probable decrease in the content of glucose (by 24.5%), total protein and albumin (by 16.1 and 26.2%, respectively, p<0.05) with a simultaneous increase in the content of indicators of nitrogen metabolism in the blood. In addition, nutritionally deficient animals had a 4.7-day delay in wound healing compared to the control group. The use of arginine glutamate, in food-deprived rats caused a reduction in the wound skin defect and was accompanied by a partial normalization of metabolic processes: the total protein content and the amount of blood albumin were higher than those in the model pathology group without correction by 10.2 and 12.9%, respectively (p<0.05), the glucose content increased (+12.2%); simultaneously blood urea content was lower by 25.2% (p<0.05). Conclusion. The obtained data are an experimental basis for further clinical studies of the possibility of practical use of arginine glutamate in the complex treatment of patients with wound processes, especially under conditions of nutritional insufficiency

The effect of partial food deprivation on the astroglia in the dorsal subnucleus of the lateral septum of the rat brain

The effect of 40% partial food deprivation was studied on the immunohistochemically detectable amount of glial fibrillary acidic protein (GFAP) - the specific marker of astroglia - in the dorsal subnucleus of lateral septum (LS) of male, intact and ovariectomized (OVX) female rats. Animals were either fed ad libitum (control) or 40% food deprived for one week, then perfusion-fixed, their brains removed, and serial vibratome sections were processed for the immunocytochemical localization of GFAP. Computeraided densitometry was carried out on digital photographs.The results showed that ovariectomy alone did not exert any effect on the density of GFAPimmunoreactivity (GFAP-IR) as compared to the values detected in intact females. Food deprivation increased the density of GFAP in each experimental group. The difference was most pronounced in males, significant in females and much less in ovariectomized females. Parietal cortex chosen as reference area did not show any increase in the local GFAP-IR.It was previously shown that the dorsal subnucleus of the lateral septum reacts with plastic neurochemical changes to food deprivation. Our results prove that these changes affect not only neuronal but also glial elements.

Metabolic responses to prolonged starvation, food restriction, and refeeding in the brown trout, Salmo trutta: Oxidative stress and antioxidant defenses

The effects of long-term starvation and food restriction (49 days), followed by refeeding (21 days) have been studied with respect to antioxidant defense in the liver and gills (branchial tissues) of the brown trout, Salmo trutta. Malondialdehyde levels in both tissues increased in parallel with starvation and food restriction and these values did not return to normal after the refeeding period. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in liver and gills increased during the 49 days of starvation, but glucose-6-phosphate dehydrogenase (G6PD) activities decreased. Glutathione S-transferase (GST) activity decreased in the liver at the 49th day of starvation, but increased in the branchial tissues. Some of the antioxidant enzyme activities (such as hepatic GST and branchial G6PD) returned to control values of fed fish after the refeeding period, but others (e.g. hepatic SOD and branchial GPx) did not return to normal values. In conclusion, our study indicates that total or partial food deprivation induces oxidative stress in brown trout.

Changes of GFAP-immunoreactivity after partial food deprivation in the lateral septum of female and ovariectomized rats

Event Abstract Back to Event Changes of GFAP-immunoreactivity after partial food deprivation in the lateral septum of female and ovariectomized rats Balázs Szőke1* and Katalin Halasy1 1 Szent Istvan University , Department of Anatomy and Histology, Hungary Neural elements in the lateral septum (LS) of rats react sensitively to food deprivation. It is still not known whether these changes include plastic rearrangements of synaptic connections. A reliable indicator of such changes is the detection of glial fibrillary acidic protein (GFAP), a specific marker of astroglia. In previous studies after partial food deprivation significant increase in the amount of GFAP-immunoreactive elements of the LS of male rats was observed. Our aim was to reveal density changes of GFAP-immunoreactive glial elements in intact and ovariectomized female rats after partial food deprivation. Female Wistar rats were grouped: intact and ovariectomized fed ad libitum (n=4-4), intact and ovariectomized food deprived (n=4-4). After one week animals were transcardially perfused with 4% paraformaldehyde then 60 m vibratome serial sections were cut from the LS in the coronal plane and incubated for the detection of GFAP at light microscopic level. Sections were digitally photographed and photos were evaluated with computer-assisted densitometry. Roughly even density of GFAP was measured along the rostrocaudal axis of the LS in control animals. As a result of partial food deprivation, a significant increase of GFAP-immunoreactive elements could be detected in the LS of both intact and ovariectomized female rats. Thus, the density of GFAP immunoreactivity seems to be independent of the amount of gonadal hormones, and the measured changes were due exclusively to food deprivation. Our previous and recent results prove that the LS react with marked neurochemical changes to partial food deprivation affecting both neural and glial elements. Conference: 12th Meeting of the Hungarian Neuroscience Society, Budapest, Hungary, 22 Jan - 24 Jan, 2009. Presentation Type: Poster Presentation Topic: Homeostatic regulatory mechanisms Citation: Szőke B and Halasy K (2009). Changes of GFAP-immunoreactivity after partial food deprivation in the lateral septum of female and ovariectomized rats. Front. Syst. Neurosci. Conference Abstract: 12th Meeting of the Hungarian Neuroscience Society. doi: 10.3389/conf.neuro.01.2009.04.021 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Feb 2009; Published Online: 26 Feb 2009. * Correspondence: Balázs Szőke, Szent Istvan University, Department of Anatomy and Histology, Budapest, Hungary, aliscaszb@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Balázs Szőke Katalin Halasy Google Balázs Szőke Katalin Halasy Google Scholar Balázs Szőke Katalin Halasy PubMed Balázs Szőke Katalin Halasy Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Endocannabinoids, feeding and suckling – from our perspective

In this overview we have summarized some aspects of our published work related to the effects of the endocannabinoid system on appetite and suckling. As noted also by several other groups we have found that anandamide, a major endocannabinoid, enhances appetite in mice. On partial or full food deprivation over 24 h the levels of 2-arachidonoyl glycerol (2-AG), a second major cannabinoid, are initially elevated in mouse brain; however, partial food deprivation over a longer period causes reduction of 2-AG levels. Blocking the endocannabinoid system with a CB1 antagonist on the 1st day after birth leads to inhibition of suckling; later administration also affects suckling, but does not fully block it.

Compensatory growth in fishes: a response to growth depression

AbstractCompensatory growth (CG) is a phase of accelerated growth when favourable conditions are restored after a period of growth depression. CG reduces variance in size by causing growth trajectories to converge and is important to fisheries management, aquaculture and life history analysis because it can offset the effects of growth arrests.Compensatory growth has been demonstrated in both individually housed and grouped fish, typically after growth depression has been induced by complete or partial food deprivation. Partial, full and over‐compensation have all been evoked in fish, although over‐compensation has only been demonstrated when cycles of deprivation and satiation feeding have been imposed. Individually housed fish have shown that CG is partly a response to hyperphagia when rates of food consumption are significantly higher than those in fish that have not experienced growth depression. The severity of the growth depression increases the duration of the hyperphagic phase rather than maximum daily feeding rate. In many studies, growth efficiencies were higher during CG. Changes in metabolic rate and swimming activity have not been demonstrated yet to play a role.Periods of food deprivation induce changes in the storage reserves, particularly lipids, of fish. Apart from the strong evidence for the restoration of somatic growth trajectories, CG is a response to restore lipid levels. Although several neuro‐peptides, including neuropeptide‐Y, are probably involved in the control of appetite, their role and the role of hormones, such as growth hormone (GH) and insulin‐like growth factor (IGF), in the hyperphagia associated with CG are still unclear.The advantages of CG probably relate to size dependencies of mortality, fecundity and diet that are characteristic of teleosts. These size dependencies favour a recovery from the effects of growth depression if environmental factors allow. High growth rates may also impose costs, including adverse effects on future development, growth, reproduction and swimming performance. Hyperphagia may lead to riskier behaviour in the presence of predators. CG's evolutionary consequences are largely unexplored. An understanding of why animals grow at rates below their physiological capacity, an evaluation of the costs of rapid growth and the identification of the constraints on growth trajectories represent major challenges for life‐history theory.

Impact of low-molecular ovarian peptides on reproductive function inhibited by partial food deprivation

A preparation of total low-molecular peptides isolated from bovine ovaries by acetic acid extraction was tested for its impact on the reproductive function of rats inhibited by partial food deprivation. Three five-day courses of once-daily injections of the preparation at 5 mg/kg restored the number of growing follicles and ovulating ova, estrous cycle duration, and uterine and ovarian weight to their levels found in intact rats.

GABAergic deafferentation hypothesis of brain aging and Alzheimer's disease; pharmacologic profile of the benzodiazepine antagonist, flumazenil.

Recent experiments have shown that: 1) A chronic 10 month daily administration to rats of the benzodiazepine (BDZ) receptor antagonist, flumazenil (FL; 4 mg/kg in drinking water), from the age of 13 through 22 months, significantly retarded the age-related loss of cognitive functions, as ascertained by the radial arm maze tests conducted two months after FL withdrawal. 2) An equal number of 8 rats died in the control and FL-treated group before the behavioral tests were completed and the animals were sacrificed; the life span of the FL-treated 8 rats equaled 24.0 (+/- 0.6 SEM) months, while that of the control 8 rats equaled 22.3 months (+/- 0.7 SEM), and the group difference was marginally significant (p = 0.04 Mann-Whitney test). 3) In rats sacrificed 3 months after FL withdrawal and behavioral testing, the protective action of FL, relative to age-matched controls, was revealed by a significant reduction in the age-related loss of neurons in the hippocampal formation. 4) In the time period of 3 months between the drug withdrawal and sacrificing of the animals, stress experienced by the aging rats during behavioral testing, related to excessive daily handling of the animals and partial food deprivation to motivate them to perform in the radial arm maze, apparently had excitotoxic effects on the hippocampal neurons, as indexed by the presence of 30% neurons in a state of moderate pyknosis found both in the FL group and the age-matched controls. In the 6 months "young" control group, the number of pyknotic neurons equaled only 3.5%. It was concluded that the drug withdrawal and stress of behavioral testing unleashed the previously FL-controlled age-related degeneration. On the basis of these results and the literature, showing that the tone of the GABAergic system increases with age, and particularly in Alzheimer's disease (AD), the hypothesis of brain aging was formulated. It postulates that in mammals, with growing age, and prematurely in humans with AD, the increasing tone of the BDZ/GABAergic system interferes with antero- and retrograde axonal transport through a chronic depolarizing block of preterminal axon varicosities of the ascending aminergic and cholinergic/peptidergic systems, which are indispensable for normal metabolic/trophic glial-neuronal relationships. Such a state leads to discrete anatomic deafferentation of forebrain systems, and particularly of the neocortex, where block of the anterograde axonal transport results in induction of the cortical mRNA responsible for synthesis of the beta-amyloid precursor protein (beta APP). The simultaneous block of retrograde transport from chronically depolarized preterminal axon varicosities may account for toxic accumulation in cortex of the nerve growth factor (NGF) and other trophins, without which the basal forebrain cholinergic neurons degenerate. The general pharmacologic profile of FL has been discussed on the basis of FL administration to animals and healthy and diseased humans. This profile shows that FL: 1) increases brain metabolic functions; 2) reduces emotional responses, thereby stabilizing the functions of the autonomic system in both humans and animals challenged by adverse environmental stimuli; 3) improves cognitive and coordinated motor functions in both humans and animals; 4) uniquely combines anxiolytic, vigilance and cognitive enhancing, i.e. nootropic, properties, which may, in part, stem from FL-induced emotional imperturbability (ataraxy); 5) facilitates habituation of healthy humans and animals to novel but inconsequential environmental stimuli, and promotes non-aggressive interactions among animals; 6) in single i.v. doses, and administered chronically to humans, FL has antiepileptic actions in the Lennox-Gastaut syndrome and other forms of epilepsy characterized by "spike-and-dome" EEG patterns; these actions are likely to depend on FL's disinhibition of the serotonin system; 7) administered in single i.v...

Effects of semistarvation on transintestinal D-glucose transport and D-glucose uptake in brush border and basolateral membranes of rat enterocytes.

The present work shows that semistarvation (8-10 g of food for 10 days) increases net D-glucose, Na+ and water transport in the everted and perfused rat jejunum. A linear and positive correlation between cell sugar concentration and transport was found in control and semistarved rats, but the phenomenon was more relevant only in semistarved animals. Membrane vesicle experiments showed that semistarvation increases sugar overshoot only in brush border membrane vesicles, while this situation does not occur in basolateral membrane vesicles. The effect of partial food deprivation seems to enhance net sugar transport by increasing sugar entry across the apical membrane of enterocytes.

The influence of partial food deprivation on the quantity and source of triiodothyronine in several tissues of athyreotic thyroxine-maintained rats.

In the present study the influence of partial food deprivation (PFD) on the quantity and source of T3 [i.e. T3 derived from local T4 to T3 conversion (Lc T3 (T4] vs. plasma-derived T3] in several rat tissues was investigated. Two groups of athyroid rats on a synthetic diet received a continuous iv infusion consisting of T4 (1.0 microgram/100 g BW X day), [125I]T4, and [131I]T3 over a prolonged period. For one group of rats the daily food intake was restricted by one third to maintain constant BW during the infusion period. At isotopic equilibrium the mean plasma T3, T4, and TSH levels for control-fed rats were: 38 ng/dl, 5.1 micrograms/dl, and 470 ng/ml, respectively. The values for rats on PFD were T3: 22 ng/dl, T4: 4.8 micrograms/dl, TSH: less than 70 ng/ml. The [125I]T3 and [131I]T3 contents of whole homogenates from liver, kidney, thigh muscle, cerebral cortex, cerebellum, and anterior pituitary gland as well as the subcellular fractions from liver, kidney (nuclei, mitochondria, microsomes, and cytosol), and anterior pituitary gland (nuclei) were determined (after extraction in ethanol) by thin layer chromatography. The contribution of Lc T3(T4) and the total T3 levels in these tissue preparations could then be calculated. In the cerebral cortex, cerebellum, and anterior pituitary gland of PFD rats plasma-derived T3 as well as Lc T3(T4) was decreased. The total T3 level in the liver did not change under PFD, owing to an increase in Lc T3(T4). It is possible that the release of hepatic Lc T3(T4) into the blood stream was reduced. In neither group was there appreciable Lc T3(T4) in muscle. In contrast to the other tissues investigated, the [131I]T3 tissue-plasma ratio for muscle had increased under PFD, suggesting a higher uptake of T3. As a consequence, the T3 levels in the muscles of PFD rats did not differ from those in normally fed animals. For both groups of rats the contribution of Lc T3(T4) in hepatic nuclei was far lower than that found for the other hepatic cellular fractions. This would suggest that the hepatic nucleus preferentially takes up plasma-derived T3. In both control-fed and PFD rats the bulk of renal T3 appeared to be exchangeable with plasma T3. Hence the T3 levels in renal nuclei were reduced under PFD. The nuclear T3 levels in the anterior pituitaries from PFD rats were markedly decreased. Therefore it is likely that other factors determine TSH secretion under PFD.

Indomethacin potentiates the operant behavior suppressant and rectal temperature lowering effects of low doses of d-amphetamine in rats

Prostaglandins (PGs) may be important in modulating the actions of d-amphetamine. To test this hypothesis male rats were pretreated with indomethacin to inhibit PG synthesis before d-amphetamine was injected. Indomethacin (5 mg/kg, IP) was found to be without direct effect upon fixed-ratio behavior or rectal temperature, but significantly enhanced the capacity of low doses of d-amphetamine to suppress behavior and lower temperature. These effects were not due to partial food deprivation or to an increase in the concentration of d-amphetamine in brain. It is concluded that one or more of the PGs modulate the central actions of d-amphetamine, perhaps by modifying the release and/or reuptake of catecholamines, or through a postsynaptic action.

The effect of aging on rat tissue content of moisture, protein, zinc, copper, and manganese with partial food deprivation: II. Middle stages of aging

Underfeeding (50% ad libitum) resulted in marked retardation of growth which was nearly a 50% reduction at 12 months of age for males and a 34% reduction for females. The retardation of female growth was not as severe as that of male. Various organ weights showed a pattern similar to total body growth. Moisture content tends to decrease with age but it is statistically insignificant. Protein concentration of male showed a gradual increase up to eight months, then remained constant throughout the test period. Unlike protein content in the male, female protein concentration remained fairly constant from one to twelve months in ad libitum feeding. However, protein levels in 50% ad libitum female tissues tended to decrease with age. Zinc content in liver, kidney, and brain showed a gradual increase to 8 months then decreased. Zinc content in bone showed a rapid increase before leveling off. The zinc level in the bone was consistently higher than any other tissues examined. A gradual increase was observed in copper content of liver and kidney in the ad libitum fed groups whereas a rapid increase was observed in the 50% ad libitum fed group before leveling off to relatively constant concentrations. Manganese levels in all tissues remained constant except in the brain. Brain manganese content tended to increase with age. Among the parameters studied, there was a significant retardation of organ and body growth with diet manipulation. Supplementation of trace minerals (Cu, Mn, Zn) in the diet reduced mortality rate. Protein content was the only significant difference observed between sexes or dietary groups.

Effects of subdiaphragmatic vagotomy on schedule induced drinking and schedule dependent lever pressing

Fourteen male albino rats reduced in body weight were exposed to a daily 1 hr FI-1 min schedule of food reinforcement. When schedule induced licking and drinking and schedule dependent lever pressing stabilized, seven animals were subjected to bilateral subdiaphragmatic vagus nerve transections and the other seven animals were subjected to sham operations. Changes in licking, drinking, and lever pressing were assessed when animals were reduced to 80% of their initial body weight by partial food deprivation and when body weights recovered after the animals were returned to conditions of ad lib feeding. Results indicate that vagotomy produces a significant decrease in schedule induced licking and drinking when animals are at reduced body weight. When vagotomized rats are allowed to recover body weight due to ad lib feeding, lever presses decrease but licking and drinking are not further reduced. The sham operation had no appreciable effects at reduced body weight. When allowed to recover body weight sham animals exhibited significant decreases in licking, drinking, and lever pressing. In addition, the rate of body weight gain and home cage food and water consumption and water consumed in response to hypertonic saline injections were reduced in vagotomized animals when allowed to feed ad lib. Results are discussed in terms of vagal afferent activity from the viscera to the lateral hypothalamus associated with food deprivation and body weight reduction and the maintenance of adjunctive behavior.

Effects of caffeine on FT-1 min schedule induced drinking at different body weights

The effects of caffeine (3.125, 6.25, 12.5, 25.0, 50.0, and 100.0 mg/kg) on lever pressing, schedule induced licking, and water consumption induced by a fixed time 1 min schedule of food reinforcement were studied. Changes in these dependent variables were assessed when animals were reduced to 80% of their initial body weight by partial food deprivation and when body weight recovered after the animals were returned to conditions of ad lib feeding. Results indicate similar decreases in licking and drinking at the highest doses of caffeine under both feeding and body weight conditions. The results were compared to previous research which evaluated the effects of caffeine on adjunctive behavior.

Effects of methylphenidate on food and water consumption at different body weights.

Abstract The effects of intraperitoneally administered methylphenidate at 0, 1.5, 3.0, 6.0, and 12.0 mg/kg were studied in two experiments. Experiment 1 determined the effects of methylphenidate on 0.5, 1.0, 2.0, and 24 hr post injection food and water consumption in rats at ad lib feeding body weights. Experiment 2 determined the post injection effects of methylphenidate on 0.5, 1.0 and 2.0 hr food and water and 24 hr water consumption in rats maintained at 80% ad lib feeding body weight due to partial food deprivation. The results of Experiment 1 indicate that when animals are feeding ad lib at normal body weight food and water consumption is decreased for 2 hr following the administration of the lowest 1.5 mg/kg dose of methylphenidate. Methylphenidate in doses as high as 12.0 mg/kg has no effect on 24 hr food and water consumption under these conditions. The results of Experiment 2 indicate that when animals are maintained at reduced body weight due to partial food deprivation, food consumption for 2 hr is significantly decreased by the highest, 12.0 mg/kg, dose of methylphenidate. These effects are observed within the first 30 min post injection when methylphenidate decreases food consumption in a dose dependent manner. Methylphenidate has no effect on water consumption under these conditions. The effects of methylphenidate on ingestive behavior are discussed in terms of previous experiments and the possible differential effects on motor activity at different body weights under different stimulus conditions.