Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STARVATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,711 records · Page 95Linked to original sources
PubMed2002

The contribution of starvation, deconditioning and ageing to the observed alterations in peripheral skeletal muscle in chronic organ diseases.

Muscle weakness and early fatigue are common symptoms of chronic organ diseases, like chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF) and chronic renal failure (CRF). It is becoming more and more clear that symptom intensities and exercise intolerance are related to muscle wasting and intrinsic alterations in peripheral skeletal muscle in these patient populations, while correlations with parameters of organ functioning are poor. Also, changes in muscle structure and function in COPD, CHF and CRF show much resemblance. Semi-starvation, reduced physical activity and ageing are external factors possibly confounding a direct relationship between the primary organ impairments and alterations in peripheral skeletal muscle and exercise capacity. Reducing the catabolic effects of the various contributing factors might improve muscle function and health status in chronic disease. In this review, we present a systematic overview of human studies on alterations in skeletal muscle function, morphology and energy metabolism in COPD, CHF, CRF and we compare the results with comparable studies in anorexia nervosa, disuse or inactivity and ageing. Unravelling the relative contributions of these external factors to the observed alterations in the various diseases may contribute to targeted intervention strategies to improve muscle function in selected groups of patients.

Aging↗
PubMed1978

Thyroxine inactivation by starvation in cultured hepatocarcinoma cells, Formation of reverse triiodothyronine.

The effect of starvation on thyroid hormone metabolism was studied in monkey hepatocarcinoma monolayer cultures. Nonphenolic ring monodeiodination of thyroxine, 3, 5, 3'-triiodothyronine and 3, 3'-diiodothyronine was accelerated. Since phenolic ring deiodination of 3, 3',5'-triiodothyronine (reverse T3) was unaffected, this metabolite accumulated in the medium during thyroxine metabolism. This suggests that increased serum reverse T3 in malnourished humans may be caused by enhanced deiodination of thyroxine rather than decreased rT3 catabolism.

Animals↗
PubMed1988

The effect of maturation on insulin secretion after starvation in isolated perfused rat pancreas.

To determine the effect of maturation on glucose-induced insulin release after starvation, we investigated the insulin release from perfused pancreas of young adult rats after fasting for 18-20 hr. In the rats weighing 300-400 g (12-14 w) and 200-250 g (7-8 w), the glucose-induced insulin secretion from perfused pancreas of starved rats was similar to that of fed rats. While, in the rats weighing 100-150 g (4-5 w), both the first and the second phase of glucose-induced insulin secretion from perfused pancreas of starved rats was markedly decreased compared with that of fed rats. These results suggest that insulin response to glucose is not matured in young below 150 g (5 w).

Aging↗
PubMed1989

Effect of postnatal starvation on the 5 alpha-reductase activity of the brain and of the isolated myelin membranes.

The 5 alpha-reductase, the enzyme which converts testosterone into its major "active" metabolite (dihydrotestosterone, DHT), has been found to be present in high concentration in brain structures particularly rich of myelin (white matter structures), as well as in myelin membranes. Previous ontogenetic observations seem to indicate that, during the process of myelinogenesis, the enzyme might be synthesized in the oligodendrocytes, and subsequently incorporated into the myelin membranes. It is well established that postnatal malnutrition produces a decreased formation of myelin, when starvation is performed from birth until to the 2nd or 3rd week of life; on the contrary food deprivation does not produce any significant effect on myelin accumulation when performed after the 14th day of life. The present experiments have been performed in the rat in order to study the effects of postnatal undernutrition (from birth to the 19th day of life: long malnutrition; and from the 14th to the 19th day of life: short malnutrition) on the 5 alpha-reductase activity present in the following brain structures: cerebral cortex, hypothalamus, corpus callosum, pyramidal tract, as well as in isolated myelin membranes. Undernourished animals have been killed at 20 days of age. Normally nourished animals served as controls. Long undernutrition induced a statistically significant decrease of the formation of DHT in the corpus callosum and in the pyramidal tract vs controls. On the contrary, the nutritional deficiency did not decrease the 5 alpha-reductase activity in the cerebral cortex and in the hypothalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1993

Corticosteroid-binding globulin levels in the rat serum under conditions of starvation and restriction of motions.

Serum corticosteroid-binding globulin (CBG) concentrations were measured by a radioligand method in rats under the action of some factors influencing activity of pituitary-adrenal system. Basal CBG levels were about 2-fold higher in females than in males. In females only starvation resulted in a significant lowering of CBG activity, while in males CBG was affected only by restriction of motions for 5h Ether treatment in both sexes, pregnancy in females and adrenalectomy in males did not influence CBG levels.

Adrenalectomy↗
PubMed1982

Starvation and age effects on glycoregulation and hormone levels of C57BL/6Job/ob mice.

The contributions of insulin (IRI), glucagon (IRG), and corticosterone production to the glycemic changes associated with age and starvation were examined in 3 and 6 month old ob/ob and lean mice. Three month old ob/ob mice had elevated glucose levels under all feeding conditions, but in older obese mice basal hyperglycemia was evident only after 48 hours of food deprivation. These age differences in glycoregulation were not consistently related to changes of IRI, IRG, or corticosterone concentrations. Similarly, the mild diabetes associated with senescence in lean mice was only evident during food deprivation. This abnormality in glycoregulation was also independent of decreased IRI or elevated diabetogenic hormone concentrations. Our results indicate that there is no simple hormonal basis for the partial remission of diabetes in older ob/ob mice, or for the development of mild diabetes in aging lean mice. Additionally, these data suggest that the tissue 'resistance' that is associated with chronic insulin overproduction might also develop in response to persistent overproduction of other metabolically-active hormones.

Age Factors↗
PubMed1981

Effects of starvation in rats on serum levels of testosterone, dihydrotestosterone and testicular 3 beta-hydroxysteroid dehydrogenase activity.

Adult male rats were maintained on the following dietary regimes: full-fed for 28 days (controls); full-fed 21 days followed by no feed for seven days (acutely starved); no feed for seven days followed by 1/4 feed for 14 days (chronically starved); no feed for seven days, 1/4 of the normal diet for 1/4 days, and completes return of feed for seven days (refed). Serum testosterone (T) and dihydrotestosterone (DHT) were measured by radioimmunoassay and testicular delta 5-3 beta-hydroxysteroid-dehydrogenase (3 beta-HSD) activity was measured by a pregnenolone depletion method. Prostate, seminal vesicles and seminal fluid weight, as well as number of epididymal spermatozoa were reduced in all starved groups. Serum androgens and testicular delta 5-3 beta-HSD activity were significantly reduced in acutely and chronically starved rats. After seven days of refeeding, serum levels of T, DHT, as well as testicular 3 beta-HSD activity rose to control values. In addition, the accessory organ weights and number of epididymal spermatozoa followed a similar pattern. These data provide further evidence that starvation results in impaired testicular function which is reversed by refeeding.

3-Hydroxysteroid Dehydrogenases↗
PubMed1981

Plasma concentrations of glucose, corticosterone, glucagon and insulin and liver content of metabolic substrates and enzymes during starvation and additional hypoxia in the rat.

The plasma levels of corticosterone, insulin and glucagon, and the concomitant changes in the levels of several liver enzymes and metabolites were measured in intact rats in the basal state during 24 hours and under conditions of food deprivation and hypoxia. The levels of the following enzymes and metabolites were examined: phosphoenolpyruvate carboxykinase, glucose-6-phosphatase, pyruvate kinase, phosphofructokinase, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, glucose, glucose-6-phosphate, glycogen, fructose-6-phosphate, hexokinase, tyrosine amino-transferase and tryptophan oxygenase. During food deprivation, the increased gluconeogenesis is possibly a result of glucagon activity. In contrast, however, during hypoxia the increase in gluconeogenesis seems to be a result of the higher plasma level of corticosterone. During starvation, the insulin concentration dropped steadily and came close to zero.

Animals↗
PubMed2005

Carbon starvation in glacial trees recovered from the La Brea tar pits, southern California.

The Rancho La Brea tar pit fossil collection includes Juniperus (C3) wood specimens that 14C date between 7.7 and 55 thousand years (kyr) B.P., providing a constrained record of plant response for southern California during the last glacial period. Atmospheric CO2 concentration ([CO2]) ranged between 180 and 220 ppm during glacial periods, rose to approximately 280 ppm before the industrial period, and is currently approaching 380 ppm in the modern atmosphere. Here we report on delta13C of Juniperus wood cellulose, and show that glacial and modern trees were operating at similar leaf-intercellular [CO2](ci)/atmospheric [CO2](ca) values. As a result, glacial trees were operating at ci values much closer to the CO2-compensation point for C3 photosynthesis than modern trees, indicating that glacial trees were undergoing carbon starvation. In addition, we modeled relative humidity by using delta18O of cellulose from the same Juniperus specimens and found that glacial humidity was approximately 10% higher than that in modern times, indicating that differences in vapor-pressure deficits did not impose additional constrictions on ci/ca in the past. By scaling ancient ci values to plant growth by using modern relationships, we found evidence that C3 primary productivity was greatly diminished in southern California during the last glacial period.

Atmosphere↗
PubMed1996

The RNA chain elongation rate of the lambda late mRNA is unaffected by high levels of ppGpp in the absence of amino acid starvation.

In this study, the effects of high levels of guanosine tetraphosphate (ppGpp) on the decay and RNA chain elongation kinetics of the bacteriophage lambda late transcript in Escherichia coli were examined in the absence of amino acid starvation. The accumulation, mRNA decay kinetics, and RNA chain elongation rate of the lambda late mRNA were determined after heat induction of lambdacI857 lysogens in the presence of high levels of ppGpp induced from a RelAalpha fragment-overproducing plasmid. The accumulation kinetics and elongation rate determinations of the late mRNA were made at long times after induction to allow a new steady state of transcriptional activities under conditions of elevated intracellular levels of ppGpp. The results indicate no prolonged or significant effect on either mRNA decay or the RNA chain elongation rate of the late mRNA as a result of elevated ppGpp levels. Surprisingly, the RNA chain elongation rate determinations indicate an RNA polymerase processivity of approximately 90-100 nucleotides/s for the lambda late transcript despite the presence of high levels of ppGpp. The results are discussed in terms of various models for regulation of stable and messenger RNA synthesis in E. coli.

Amino Acids↗
PubMed2001

LeuO expression in response to starvation for branched-chain amino acids.

The recently identified role of LeuO in the regulation of transcription has prompted us to search for the specific function(s) of LeuO in bacterial physiology. The cryptic nature of expression of leuO has previously limited such analysis. A conditional leuO expression was found when bacteria enter stationary phase and was shown to be guanosine 3',5'-bispyrophosphate-dependent. Multiple physiological events, including the stringent response, are induced upon the increase of the bacterial stress signal, guanosine 3',5'-bispyrophosphate. In this study, we tested whether LeuO was directly involved in the bacterial stringent response. LeuO was shown to be indispensable for growth resumption following a 2-h growth arrest caused by starvation for branched-chain amino acids in an E. coli K-12 relA1 strain. This result supports a functional role for LeuO in the bacterial stringent response.

Amino Acids, Branched-Chain↗
PubMed1985

Influence of feed intake and starvation on the magnitude of Na+,K+-ATPase(EC 3.6.1.3)-dependent respiration in duodenal mucosa of sheep.

Oxygen consumption and Na+,K+-ATPase(EC 3.6.1.3)-dependent (ouabain-sensitive) and -independent respiration were measured for duodenal mucosa biopsies from 10-month-old sheep given two levels of digestible energy (DE) intake (7.6-7.7 and 14.8 MJ lucerne (Medicago sativa) pellets/d) and following 48 h of starvation. The mucosal biopsies were determined to be structurally intact and free of adherent bacteria on histological and scanning-electron-microscope examinations. The use of D-glucose as a substrate during incubations did not elevate (P greater than 0.05) the respiration indices of the biopsies over those measured during acetate incubations. Glucose uptake did not (P greater than 0.05) influence the Na+,K+-ATPase-dependent respiration of the mucosal biopsies. Na+,K+-ATPase-dependent respiration accounted for 50% of the total O2 consumption of the mucosal biopsies of sheep given the lower level of DE. Total O2 consumption of the duodenal mucosa was not (P greater than 0.05) increased when sheep were given the higher level of DE but Na+,K+-ATPase-dependent respiration of the mucosa was elevated (P less than 0.01) by 37% during this period. When sheep were starved for 48 h, total O2 consumption of the mucosal biopsies was not (P greater than 0.05) affected, however, Na+,K+-ATPase-dependent respiration of the biopsies dropped (P less than 0.01) by 45%. Na+,K+-ATPase-dependent respiration accounted for 61.3% of the O2 uptakes of mucosa from the sheep given the higher level of DE and 28.3% of the O2 uptake of mucosa from fasted sheep.

Animals↗
PubMed1985

Relationship between starvation heat production and body size in the domestic fowl.

The relationship between starvation heat production (SHP) in kJ/d and body weight (W) in kg for the domestic fowl was examined by compiling calorimetric data on 78 immature and 222 mature fowls. Linear regression analyses were performed after transformation of the data to a logarithmic scale (base = 10). The derived relationship (re-transformed) for mature birds was found to be: SHP = 406 W0.602 The weight exponent (b) was significantly (P less than 0.01) different to the value of 0.75 normally used for mature birds.

Age Factors↗
PubMed1988

A longitudinal study of starvation in piglets and the introduction of a modified liver biopsy technique.

The effect of starvation on blood glucose, muscle glycogen and liver glycogen concentration was measured in a group of newborn piglets. Liver biopsies were obtained by using a modified version of the Menghini technique. No difference in length of survival time was observed between piglets that received water and those that did not. Piglets with higher birth weight survived longer. No relationship was found between initial liver glycogen content and survival time. Moreover, we concluded that plasma glucose levels are not reliable indicators of length of survival time. The interrelated changes in liver glycogen, muscle glycogen, and plasmaglucose concentrations found in this study correspond with those reported elsewhere. Moreover, the number of experimental animals needed for the study was markedly reduced. We conclude that the liver biopsy technique is valuable in longitudinal hypoglycaemia studies of piglets.

Animals↗
PubMedDate not supplied

Contrasting responses to desiccation and starvation by eggs and neonates of two lepidoptera.

We examined the effects of desiccation on eggs and first-instar larvae of two species of Lepidoptera, Grammia geneura (Arctiidae) and Manduca sexta (Sphingidae). Grammia geneura occurs primarily in grasslands and savannas of the southwestern United States; M. sexta co-occurs with G. geneura but also is cosmopolitan across much of the Western Hemisphere. Eggs of G. geneura exposed to 0% relative humidity (RH) lost water much less rapidly (7.6 microg d(-1); 2.4% d(-1)) than did eggs of M. sexta (79.5 microg d(-1); 5.7% d(-1)). Eggs of both species survived at rates exceeding 75% at both 0% and 85% RH. Neonates of the two species responded differently to desiccation and starvation. In 85% RH, larval G. geneura survived at high rates (>80%) without access to food or water up to day 17, and in 0% RH, they survived at rates exceeding 50% through the first 10 d. Larvae at 0% RH lost mass very slowly (7.2 microg d(-1); 2.9% d(-1)), which was attributable both to low rates of water loss and to an ability to reduce metabolic rate to low levels. Larval M. sexta, in contrast, had rates of mortality that were much higher: after 1 d, fewer than 30% were alive in either group, and by about 1.5 d, all were dead. Neonate M. sexta also lost mass much more rapidly at 0% RH, about 329 microg d(-1). Water from metabolism appeared to contribute significantly to the water budget of G. geneura but not of M. sexta. These data show that G. geneura and M. sexta can inhabit similar macroclimates via remarkably different physiologies.

Animals↗
PubMed1981

Blood and tissue branched-chain amino and alpha-keto acid concentrations: effect of diet, starvation, and disease.

Branched-chain alpha-keto and amino acid (BCKA, BCAA) concentrations were measured in blood, plasma, and tissues of rats fed low protein (8% casein) or high protein (60% casein) diets; and in rats fed a stock diet and subjected to 3 days of starvation of chemically-induced diabetes. Concentrations of these amino and ketoacids were also measured in blood from patients with maple syrup urine disease. Valine, isoleucine, and leucine concentrations in blood from rats fed the stock diet were 124 +/- 7, 58 +/- 4 and 99 +/- 5 microM, respectively. Blood BCAA concentrations of rats fed the high protein diet and diabetic rats were elevated 2- to 3-fold; small increases were observed in blood from starved rats. Changes in blood BCAA concentrations paralleled those in tissues, except in starved rats in which the skeletal muscle free BCAA pool increased proportionately more than the circulating pool. Mean blood BCKA concentrations of rats fed the stock diet were low--7.9 +/- 0.5, 7.1 +/- 0.4 and 12.4 +/- 0.7 microM for alpha-ketoisovaleric, alpha-keto-beta-methylvaleric, and alpha ketoisocaproic acids, respectively. All treatments resulted in increases in blood BCKA concentrations of from 1.4 to 2 fold. In liver and heart, concentrations of BCKA, except for that of alpha-ketoisocaproic acid were near the limits of detection (less than 1 nmole/g). There was significant accumulation of all three BCKA in skeletal muscle which was estimated to contain about 80% of the measured body free BCKA pool. Blood BCKA are well regulated. Only in patients with maple syrup urine disease are plasma concentrations of BCKA useful indicators of altered tissue BCAA metabolism. Skeletal muscle, where oxidation of the BCKA is limited by low BCKA dehydrogenase activity, would seem to be the major source of circulating BCKA.

Amino Acids, Branched-Chain↗
PubMed1984

Influence of starvation on sucrase regulation by dietary sucrose in the rat.

We have studied the action of sucrose on jejunal sucrase activity. Rats (175 g) were first starved or fed a digestible carbohydrate-free diet for 60 h and then fed a high sucrose diet for varying times up to 84 h. 1) Rats starved for 60 h showed mucosal atrophy with a decrease in protein content/10 cm (18.00 +/- 1.4 versus 40.1 +/- 3 mg (controls p less than 0.001) and in villus height (357 +/- 18 versus 526 +/- 5 microns, p less than 0.001) which was fully repaired only after 60 h on the sucrose diet (528 +/- 11 microns). Rats on digestible carbohydrate-free diet showed no mucosal atrophy. 2) Starved rats had a delayed (60 h) sucrase activity response to sucrose (53 +/- 7 versus 122 +/- 4 microns/mg protein, p less than 0.001). Maximum activity was obtained after 12 h on sucrose diet in rats maintained on the carbohydrate-free diet: 38 +/- 1 versus 108 +/- 2.3 microns/mg protein, p less than 0.001. 3) Villus and crypt cell analysis after starvation and 12 h on a high sucrose diet localized the increase in sucrase activity to the villus-crypt junction. No change occurred in the upper villus. The increase was complete all along the villus by 36 h. In contrast, after the carbohydrate-free diet, sucrase activity increased maximally at all levels of the villus by 12 h on the high sucrose diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Cardiac effects of starvation and semistarvation diets: safety and mechanisms of action.

A major concern with the use of starvation or semistarvation diets for weight reduction in severely obese people has been the reports of sudden death due to ventricular arrhythmias. Obesity per se is associated with cardiovascular changes, including left ventricular hypertrophy and prolongation of the QT interval. With weight loss, the mass of the heart and left ventricle decrease, but some signs of left ventricular dysfunction remain. The effect of weight loss on the electrocardiogram abnormalities of obesity appears to depend upon diet duration and upon whether protein and mineral nutritional status is maintained. Copper, potassium, and magnesium deficiencies may play important roles in promoting an electrically unstable heart. Stress, by eliciting autonomic imbalance, may act upon an electrically unstable heart to provoke acute arrhythmias in a subset of the obese population with QT interval prolongation.

Arrhythmias, Cardiac↗