Days Of Food Deprivation Research Articles

Food deprivation modulates γ-aminobutyric acid receptors and peripheral benzodiazepine binding sites in rats

The effect of 5 days of food deprivation followed by 5 days of refeeding on γ-aminobutyric acid (GABA) receptors, central benzodiazepine receptors (CBR), and peripheral benzodiazepine binding sites (PBzS) was studied in female Sprague-Dawley rats. Starvation induced a decrease in the density of PBzS in peripheral organs: adrenal (35%; P < 0.001), kidney (33%; P < 0.01), and heart (34%; P < 0.001). Restoration of [ 3H]PK 11195 binding to normal values was observed in all three organs after 5 days of refeeding. The density of PBzS in the ovary, pituitary, and hypothalamus was not affected by starvation. Food deprivation resulted in a 35% decrease in cerebellar GABA receptors ( P < 0.01), while CBR in the hypothalamus and cerebral cortex remained unaltered. The changes in PBzS observed in the heart and kidney may be related to the long-term metabolic stress associated with starvation and to the functional changes occurring in these organs. The down-regulation of the adrenal PBzS is attributable to the suppressive effect of hypercortisolemia on pituitary ACTH release. The reduction in cerebellar GABA receptors may be an adaptive response to food deprivation stress and may be relevant to the proaggressive effect of hunger.

Delayed effects of amphetamine or phencyclidine: Interaction of food deprivation, stress and dose

Tritium-labelled phencyclidine (PCP) hydrochloride (12 mg/kg) was injected SC for six consecutive days into two groups of eight male rats maintained at 85% of their initial free-feeding weights. Eight days after the last injection, electric footshock raised fat levels of PCP 28% over nonshocked controls, and lowered blood levels 18%, but did not alter brain levels of the drug significantly. Thus, application of an acute stressor does result in redistribution of tissue stores of phencyclidine as predicted in the literature; however, the direction of the redistributions was to fat, rather than to brain. To explore the relation of a long-term stressor (one that eliminates adipose tissue as a sink for mobilized PCP), exploratory behavior was evaluated in male rats during six days of food deprivation commencing after six daily injections of PCP HCl (2 or 4 mg/kg, SC). Exploratory behavior of the 4 mg/kg dose group was abruptly altered, compared to saline controls, at six days of food deprivation, when the rats' body weights were about 70% of initial weights and when body fat would be severely reduced or depleted. To assess replicability and generalizability of this phenomenon, PCP HCl (4 or 8 mg/kg, SC) or dextroamphetamine sulfate (3.2 or 6.4 mg/kg, SC) was injected into male rats for six days and food deprivation followed afterward for nine consecutive days, or until similar body weight reductions as in the first experiment were achieved. Again, exploratory behavior was altered in comparison to saline controls in phencyclidine-treated rats (at the 4 mg/kg dose level) when rats reached about 70% of initial weights. Behavior of dextroamphetamine-treated animals (at 3.2 mg/kg) was also different from controls, suggesting that interactions between food deprivation (stress) and lipophilic drugs of abuse occur when body fat stores reach a threshold.

Correlation of Abnormal Radular Secretion with Tissue Degrowth During Stress Periods in Helisoma trivolvis (Pulmonata, Basommatophora).

Laboratory experiments on starvation stress in Helisoma trivolvis elucidate a relationship between modifications of radular secretion and tissue degrowth resulting from stress. Tissue losses in starved adults ranged from 4.5% at 40 days to 27.7% at 160 days, with negligible mortality (<2%). Modifications in radular secretion that paralleled tissue loss involved not only abnormal secretion of individual teeth and of tooth rows, but especially an increased "packing" of radular rows per unit ribbon length. Radular length remained constant during experimental trials, however the mean number of tooth rows increased by almost 47% after 120 days of food deprivation. Radular patterns reflecting degrowth observed in these experiments were paralleled in radulae taken from overwintered animals sampled from natural populations. Rates of radular turnover averaged between 2.3% new growth per day (43 days to turnover) and 4.0% new growth per day (25 days to turnover). Radular samples could provide for post hoc detection of recent periods of tissue degrowth in snails, just as evidence of longer periods of tissue degrowth can be detected in the shells of long-lived bivalves.

Glycerylphosphorylcholine diesterase activity of uterine fluid in conditions inducing secondary sex ratio change in the rat

Food restriction or decreasing the ratio of [Na+, K+] to [Ca++, Mg++] in the diet of female rats before conception favoured the production of female offspring. Seven days of food deprivation decreased uterine fluid GPC diesterase activity in female rats, whereas long-term food restriction (21 days), rather than decreasing the enzyme activity, apparently stimulated it. Dietary Ca and Mg supplementation, likewise, produced significant decrease in GPC diesterase activity. A significantly positive correlation was observed between the levels of uterine GPC diesterase and secondary sex ratio change, which indicates that these dietary techniques of sex-ratio manipulation may modulate the uterine fluid GPC diesterase activity and influence sex determination in utero.

Effect of short-term starvation on reproductive hormone gene expression, secretion and receptor levels in male rats

The effects of 4-6 days of food deprivation on the pituitary-testicular function of adult male rats were studied. Fasting decreased body weights on average by 23% (P less than 0.01) and those of seminal vesicles by 55% (P less than 0.01) in 4 days. No consistent changes were found in testicular and ventral prostate weights. The pituitary levels of gonadotrophin-releasing hormone (GnRH) receptors decreased by 50% (P less than 0.01). Serum and pituitary levels of LH, FSH and prolactin decreased by 25-50% (P less than 0.01 for all). Testicular and serum levels of testosterone decreased by 70-80%, testicular LH receptors by 26%, those of prolactin by 50% (P less than 0.01 for all), but those of FSH remained unaffected. Acute (2 h) stimulation by a GnRH agonist (buserelin, 10 micrograms/kg i.m.) resulted in similar LH, FSH and testosterone responses in the fasted and control animals, and human chorionic gonadotrophin (hCG) stimulation (30 IU/kg i.m.) in similar increases in testosterone. A 42% decrease was found in pituitary content of mRNA of the common alpha subunit (P less than 0.05), but the mRNAs of the LH- and FSH-beta chains and prolactin were unaffected by fasting for 4 days. When the same mRNAs were measured after 6 days of fasting, the decrease of the mRNA of FSH-beta also became significant (50%, P less than 0.01). In contrast, the mRNA of LH-beta was increased twofold (P less than 0.01) at this time and serum LH levels were similar in control and starved animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle growth and composition in heavy and light breed chickens adapted to intermittent feeding

1. The effect of intermittent feeding in chickens of heavy breed (HB; meat type) and light breed (LB; egg type) on skeletal muscle growth and composition was studied in adapted and non-adapted chickens. 2. Food intake, relative to body-weight, was similar in both breeds but was higher in ad lib.-fed than in intermittently fed birds. 3. On repletion days the relative growth rate was similar in both breeds, while on depletion the LB chickens lost more weight than the HB chickens. In both breeds, the relative growth was higher in the intermittently fed birds during days of food restoration than in those fed ad lib. 4. The relative weight of the breast muscle was higher in HB birds than in LB birds, but deposition rate on the day of food restoration was similar in both breeds. This growth was more pronounced in chickens adapted to alternate feeding than in chickens exposed to this feeding regimen for one cycle. 5. Protein concentration in breast muscle was not affected by age and was slightly higher in LB chickens than in HB chickens. Soluble protein was markedly reduced on days of repletion, and more at 46 d than at 18 d of age. 6. The RNA:DNA ratio was higher in HB than in LB chickens, and lower on days of food deprivation than on days of food restoration. After repletion this ratio returned to the level of the ad lib.-fed chickens. While in LB chickens cell size (as estimated by DNA concentration) remained constant on repletion and depletion days, in the HB chickens it decreased. 7. The rapid growth of breast muscle in HB chickens was attributed to the higher rate of protein synthesis (estimated by RNA:DNA ratio) compared with LB chickens. This may also explain why the breast muscle of LB chickens was less sensitive to intermittent feeding than that of HB chickens.

Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure.

Thermogenesis in brown adipose tissue (BAT) serves as a regulator of body temperature and weight maintenance. Thermogenesis can be stimulated by catecholamine activation of adenylate cyclase through the beta-adrenergic receptor. To investigate the effects of sucrose feeding, food deprivation, and cold exposure on the beta-adrenergic pathway, adenylate cyclase activity and beta-adrenergic receptors were assessed in rat BAT after 2 wk of sucrose feeding, 2 days of food deprivation, or 2 days of cold exposure. beta-Adrenergic receptors were identified in BAT using [125I]iodocyanopindolol. Binding sites had the characteristics of mixed beta 1- and beta 2-type adrenergic receptors at a ratio of 60/40. After sucrose feeding or cold exposure, there was the expected increase in BAT mitochondrial mass as measured by total cytochrome-c oxidase activity but a decrease in beta-adrenergic receptor density due to a loss of the beta 1-adrenergic subtype. This BAT beta-adrenergic receptor downregulation was tissue specific, since myocardial beta-adrenergic receptors were unchanged with either sucrose feeding or cold exposure. In contrast, food deprivation did not alter BAT beta-adrenergic receptor density. Forskolin-stimulated adenylate cyclase activity increased in BAT after sucrose feeding or cold exposure but not after food deprivation. The ratio of isoproterenol-stimulated to forskolin-stimulated adenylate cyclase activity decreased in the sucrose-fed and cold-exposed rats but not in the food-deprived rats. These data suggest that in BAT, sucrose feeding or cold exposure result in downregulation of beta-adrenergic receptors and that isoproterenol-stimulated adenylate cyclase activity was limited by receptor availability.

Immune response of fasted calves to infectious bovine rhinotracheitis virus.

Seventeen calves (Angus, Hereford, and Angus-Hereford crosses) weighing 120-200 kg, were starved for 3 days and inoculated intranasally with a strain of IBR virus after 1 day or 3 days of food deprivation. Although clinical signs of disease were mild in all calves, the signs appeared more severe than those reported by others using the same strain of virus possibly due in part to the use of intranasal inoculation by aerosol vs instillation. Neutralizing antibody response after virus inoculation did not differ beween groups. Of the 17 calves, 16 developed significant increases (seroconversion of 4-fold increase in titre) in IBR serum antibodies. Serum neutralizing antibodies in 3 calves at inoculation did not prevent them from excreting substantial amounts of virus for ? 5 days after virus inoculation. Lymphocytes from fasted and nonfasted calves had similar (essentially negative) blast transformation responses, except 1 fasted seropositive calf (sensitised animal) that had a high stimulation index. Some dehydration was observed in fasted calves, indicated by significant increase in haematocrit. In only 1 group did serum cortisol levels rise significantly, mean values peaking at the end of fasting at the time of inoculation; thereafter, mean values tended to decline. Although the 3-day fast significantly affected some serum and blood components, it did not adversely affect the immune response of calves. One fasted calf developed a significant cell mediated immune response to inactivated IBR virus during infection. It is concluded that acute nutritional deprivation may not necessarily increase the susceptibility of calves to viral infections nor adversely affect their immune response after vaccination.&#x0D; This report represents a portion of a dissertation submitted by the senior author to the graduate faculty of the University of Missouri in partial fulfillment of the requirements for the PhD degree.&#x0D; The authors thank Gary Krause and Mark Ellersieck for aid in statistical analysis and Gerald Buening for help in lymphocyte transformation tests.

The effect of neonatal starvation on the growth, development and survival of larvae of the pine beauty moth, Panolis flammea (D & S).

Mortality of neonatal pine beauty moth larvae varied from 0% to 100% depending on the duration of food deprivation and temperature. At 20°C and 100% RH all larvae had died by the fourth day of food deprivation, whereas at 10°C and 100% RH larvae survived for twelve days without food. Although larvae were able to survive at 15°C for up to seven days without food, establishment on thier host at this temperature was seriously affected by three days of starvation. No establishment took place after four days of starvation at 15°C. At 10°C establishment was significantly affected by starvation but not to such a marked degree. Establishment at both 15°C and 10°C was enhanced if the larvae were presented with a highly suitable host. The mean relative growth rate of those larvae reaching fifth instar was unaffected by the duration of their prefeeding starvation period. However, overall mean relative growth rates of the larvae were significantly affected by the duration of the starvation period. The implications of these results are discussed in relation to the population dynamics of this insect.

Food deprivation-induced changes in the level of opioid peptides in the pituitary and brain of rat

Following 1–4 days of food-deprivation (FD) male rats were sacrificed. The pituitary and different regions of brain were analyzed for β-endorphin-like immunoreactivity (β-EI), dynorphin (dyn) and methionine-enkephalin (ME) content by RIA. Pituitary β-EI increased by 16, 28 and 43% on days 2, 3 and 4 of FD. In striatum also, β-EI increased by 140 and 176% on days 2 and 3 of FD. Dyn level in pituitary was not affected but decreased in hypothalamus by 20% and in striatum by 73% on the 4th day of FD. There was a significant decrease (33–55%) in ME levels in striatum, hippocampus and cortex on 4th day of FD. When food-deprived rats were fed for 24 hr, concentration of most of the opioid peptides returned to basal level. These results suggest that FD in rats affects the opioid peptide levels in a differential manner.

Midgut gland as monitor organ for the nutritional value of diets in Penaeus monodon (Decapoda)

Midgut gland cells of Penaeus monodon postlarvae were investigated by electron microscopy after starvation and refeeding with different diets. Well nourished postlarvae could be starved for 5 days without irreversible detriment. They recovered easily on a good diet. Only R cells were affected by a short starvation period. After 13 days of food deprivation the structures of all cell types were disintegrated. The postlarvae were able to starve for a maximum of 15 days. The most diversified ultrastructure was obtained by refeeding with cod liver oil and 2s (mixed diet). Casein was not well utilized. Sucrose was the poorest diet. The midgut gland of Penaeus monodon seems to be lipid oriented. Only fat was used as storage material; glycogen was lacking. Different ultrastructures were induced in R cells by a given diet after longer starvation periods. The reestablishment of their ultrastructure by means of a definite diet seems to be impossible after a certain period of starvation (point of no return). R cells are very sensitive to different diets. B cells show slight reactions, while F and E cells remain relatively unchanged. This indicates that R cells could be used to monitor the nutritional value of prawn diets in aquaculture.

Effect of Propionic Acid on Ketogenesis in Lactating Sheep Fed Restricted Rations or Deprived of Food

Propionic acid was used as a possible preventive agent against ketogenesis. A total of 12 Suffolk lactating sheep were allocated to groups of 4 and fed isocaloric isonitrogenous rations containing 0, 5, and 10% propionic acid for 2 wk at 1.25kg twice daily, followed by 4 days of food restriction to .5 kg/day and 2 days of food deprivation to induce ketogenesis. During the restricted feeding, concentrations of glucose in blood plasma were higher (50 to 57 versus 41 to 53 mg/dl) and concentrations of D (−)-3-hydroxybutyrate and acetoacetate lower (3.0 to 5.9 versus 3.9 to 7.6 mg/dl;.39 to .83 versus .43 to .92 mg/dl) in animals fed propionic acid. Propionic acid did not change free fatty acid concentrations of blood plasma or milk and subcutaneous fatty acid composition. Restricted feeding and fasting markedly lowered glucose and elevated concentrations of ketone bodies and free fatty acids in plasma. Furthermore, during these periods proportions of milk fatty acids containing 4 to 14 carbon atoms were decreased and those of stearic and oleic acid (18:0 and 18:1) were increased (16.6 versus 6.5%; and 41,0 versus 17.4%).

Effect of vitamin D3 (cholecalciferol) on plasma calcium and intestinal 45calcium absorption in goldfish, Carassius auratus L.

Goldfish that were fed as well as not fed for 2 weeks had similar plasma total calcium levels, and vitamin D3 injections during the last 6 days had no significant effect on this parameter. When fish were fed for 1 day after 13 days of food deprivation, plasma calcium increased significantly and this increase was augmented by vitamin D3 injections. This latter group also showed a chlorpromazine-sensitive increase in 45calcium absorption from perfused everted gut sacs when compared with the controls. It was concluded that vitamin D3 stimulates intestinal calcium absorption in the goldfish.

Prenatal stress suppresses hunger-induced rat-pup killing in Long-Evans rats

During each of the last 5 days of pregnancy, Long-Evans and Wister rats received 45 min of whole-body restraint and intense illumination. When they were 87 days old, they were placed on complete food deprivation until Day 90. At this time, all animals were tested with 1-day-old rat pups and adult mice (Mus musculus). The stress procedure suppressed the level of rat-pup killing induced by the food deprivation in the Long-Evans rats. The 3 days of food deprivation did not induce rat-pup killing in the other groups or mouse killing in any of the groups.

Catecholamine turnover in the brain and the regulation of luteinizing hormone and corticosterone in starved male rats.

The effect of starvation was studied in male Wistar rats. After only 2 days of food deprivation, LH concentrations in serum are greatly suppressed, while a significant increase in plasma corticosterone occurs after 5 days' starvation. The noradrenaline and dopamine turnover in the basal hypothalamus is decreased after 2 days. The catecholamine turnover is also reduced in the preoptic area, and in the median eminence. Injection of the catecholamine precursor L-dopa (100 mg/kg) can prevent the increase of plasma corticosterone, but not the decrease of LH. The alpha-agonist clonidine (150 micrograms/kg), but neither the beta-agonist salbutamol (0.5 mg/kg), nor the dopamine agonist apomorphine (1.0 mg/kg) can prevent the starvation induced corticosterone increase. The decrease of plasma LH is not influenced by the dopamine or noradrenaline agonists. From these data, it appears that a decreased activity of noradrenergic neurons may be responsible for the corticosterone increase in the plasma of starved rats.

Changes in certain metabolic parameters in horses associated with food deprivation and endurance exercise

Total and individual non-esterified fatty acids (NEFA), pyruvate, lactate, alpha ketoglutarate, acetoacetate, beta hydroxybutyrate, glucose and insulin were measured in horses during an 80 km endurance ride and during four days of food deprivation. In the latter group venous blood-gas and acid-base parameters, and plasma cortisol concentrations were also measured. During exercise and food deprivation the NEFA became considerably elevated, the predominant of which were oleic (35 per cent), palmitic (24 per cent), linoleic (19 per cent) and linolenic (10 per cent). By one hour after feeding total NEFA fell to approximately 20 per cent of 12 hour fasting concentrations. This was associated with a four fold rise in insulin. Small though significant increases occurred in lactate, acetoacetate and beta hydroxybutyrate after the 80 km endurance ride. It was concluded that a ketone pathway is relatively unimportant in the horse, probably due to the ability of the liver to maintain glycogenolysis.

Organization of food search in the kelp crab, Pugettia producta (Randall)

Food search was activated by chemical stimuli in specimens of the kelp crab, Pugettia producta (Randall). No differences were found between laboratory-and field-tested animals. In both, food search consisted of two components: near field (non-locomotor leg and chela probing) and far field (locomotion) search. Leg and chela probing were initiated at threshold concentrations one log unit or more below that of locomotion and were initiated prior to and in the absence of locomotion. Locomotion was limited in its activation to instances in which leg and chela probing were first initiated but failed to contact food. These results indicate that chemosensory stimuli selectively activate nearby rather than distant food search. Up to 14 days of food deprivation failed to alter this response hierarchy and threshold concentrations for near field search acts were identical for satiated and starved animals.

Leucine degradation and release of glutamine and alanine by adipose tissue.

Adipose tissue from fed rats rapidly degrades [l14C]leucine to 14C02. This process is stimulated by glucose (but not by pyruvate) and by insulin, which also enhances the degradation of isoleucine and valine. Fasting and protein deficiency markedly reduced the catabolism of [l-‘4C]leucine in epididymal fat pads by decreasing the decarboxylation of a-ketoisocaproic acid and the transamination of leucine. In tissue homogenates, the rates of these reactions decreased by 63 and 47%, respectively, after 2 days of food deprivation. Within only 1 day of food deprivation, total decarboxylation of leucine in tissue homogenates was 73% slower. In adipose tissue from the fasted animals, leutine oxidation was also stimulated by glucose but not by insulin. In fat pads from fed (but not fasted) rats, leucine decreased the oxidation of pyruvate and thus may spare use of glucose-derived acetyl coenzyme A for lipogenesis. When fed and fasted rats were injected with [1-14CJleucine, their rates of expiration of 14C02 did not differ, but when they were injected with p-‘4C]leucine, 14C02 expiration was greater in the fasted rats. Therefore, food deprivation did not affect the total amount of leucine degradation by the organism but seemed to increase the oxidation of leucine by muscle, while decreasing its conversion to triglycerides. The incubated fat pads appear to synthesize and release large amounts of glutamine and smaller quantities of alanine and glutamate. Addition of leucine increased release into the medium of glutamine and, to a lesser extent, that of alanine and glutamate (without affecting tissue protein balance or the release of other amino acids). In fasting, when degradation of leucine fell, the accumulation of glutamine and alanine in the medium decreased. Isoleucine and valine were degraded more slowly than leucine and stimulated glutamine and alanine release to a lesser extent. In adipose tissue, as in muscle, production of glutamine, as well as alanine and glutamate, seems to be the route for disposal of amino groups released in the transamination of branched-chain amino acids.

Net hepatic and splanchnic metabolism of lactate, pyruvate and propionate in dairy cows in vivo in relation to lactation and nutrient supply.

1. Circulating concentrations of glucose, propionate, lactate and pyruvate, and net exchange of these compounds across the liver and gut, were measured in lactating and non-lactating dairy cows (a) in the normal fed state, (b) before, during and after intravenous infusion of an aqueous solution of glucose, propionate or lactate (lactating cows only) in fed animals, and (c) before and during 6 days of food deprivation. 2. In the normal fed state, gut output of propionate, hepatic output of glucose and hepatic uptake of lactate were all higher in the lactating group. There was a net uptake of pyruvate across the liver in the lactating cows and a net output in the non-lactating cows. In the lactating cows there was a net uptake of lactate and pyruvate by the splanchnic bed (i.e. gut and liver combined). 3. In the lactating cows, the glucose and propionate infusions had the following effects: decrease in net hepatic uptake of lactate; a switch in pyruvate exchange across the liver from uptake to output; suppression of uptake of lactate and pyruvate by the splanchnic bed; increase in the magnitude of the liver (propionate uptake)/(glucose output) ratio. Lactate infusion did not affect hepatic propionate uptake. 4. Food deprivation increased hepatic extraction of lactate and pyruvate and decreased the liver (propionate uptake)/(glucose output) ratio in both groups. 5. It is concluded that mechanisms exist to ensure an inverse relationship between the availability to the cow of glucose or propionate and utilization by the splanchnic bed of endogenously derived lactate and pyruvate.

Dependence of sleep on nutrients' availability

Continuous EEG recordings were performed in lean (240–250 g) rats, in large size (300–380 g) rats and in Ventromedial Hypothalamic (VMH) lesioned obese (450–470 g) rats, during 4 days of food deprivation and 3 days following food restitution. Though the daily amounts of both Slow Wave Sleep (SWS) and Paradoxical Sleep (PS) were dramatically decreased in lean rats (particularly during the dark phase of the day) by the food deprivation, they remained unchanged in large size rats and also in VMH obese rats. In the latter, there was even a tendency to an increase of SWS during the first two days of starvation. Food restitution brought about a significant rebound in SWS and PS (largely based upon an increase during the dark phase of the diurnal cycle) in lean rats, but had no effect on the sleep parameters of large size and VMH obese rats. Replacement by glucose infusions (100% of the normal daily caloric intake) via a cardiac catheter of oral nutrients in food deprived rats also resulted in a similar increase of sleep duration. These findings suggest that sleep is dependent on the degree of availability of metabolizable substances at the cellular level. In addition, possible causative relations between sleep and feeding are discussed.