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PubMed1985

Use of urinary C-peptide to estimate insulin secretion during starvation.

The usefulness of measurements of urinary C-peptide excretion in indirectly assessing integrated insulin secretion during starvation was studied in eight obese subjects during a 72-h fast. Blood and urine samples were collected at 12-h intervals for measurement of insulin and C-peptide immunoreactivity. After 60 h, serum insulin and plasma C-peptide levels declined 47% and 37%, respectively, and the values were highly correlated (r = 0.8; P less than 0.001). By 72 h, urinary C-peptide excretion had declined to 70% of the level in the first 12-h period. The urinary clearance of C-peptide was not altered by starvation. A highly significant correlation was found between urinary C-peptide and C-peptide secretory rate (P less than 0.001). The molar ratio of plasma C-peptide to insulin remained constant during the fasting period. These data indicate that basal insulin secretion can be added to the list of physiological conditions in which beta-cell secretion can be effectively evaluated by urinary C-peptide measurement.

Adult↗
PubMed1987

Schizosaccharomyces pombe mutants affected in their division response to starvation.

Schizosaccharomyces pombe mutants have been selected on the basis of an altered response to nutritional stimulation of cell division (changed division response, cdr). Two new loci (cdr1 and cdr2) were identified and characterized. When suspended in nitrogen-free medium wild-type cells underwent stimulated rates of division and became reduced to approximately 30% in protein content with a concomitant 3.6-fold increase in cell number after 24 h starvation. cdr cells had significantly smaller increases in cell number. The ratio of starved/unstarved protein content was higher for the cdr strains than for the wild type. cdr cells were also affected in their response to nitrogen-source shifts from proline to glutamate (or vice versa) or when shifted from serine phosphate to inorganic phosphate, showing that the alteration in division response was not restricted to nitrogen metabolism. Upon nitrogen starvation wild-type cells arrested prior to the cdc10 execution point, whereas cdr cells arrested later in the cell cycle. cdc25-22 cdr1 or cdr2 double mutants grew very slowly and were extremely elongated at all temperatures; the restrictive temperature was reduced to 27 degrees C. wee1 was epistatic to cdr mutations with respect to cell length at the cell plate stage. cdr+ genes are postulated to play a role in the nutritional modulation of the mitotic size control.

Cell Division↗
PubMed2000

Elongation factor 2 in the liver and skeletal muscle of mice is decreased by starvation.

We examined whether starvation affected the amount of EF-2 protein as well as the level of its mRNA in the liver and skeletal muscle of mice, to understand the molecular mechanism for nutritional adaptation of protein-turnover. Although the amount of EF-2 was diminished by starvation in each of the tissues examined, the amount of EF-2 mRNA did not decrease in parallel with the protein.

Animals↗
PubMed2001

Combined effects of experimental heavy-metal contamination (Cu, Zn, and CH3Hg) and starvation on quail's body condition: parallelism with a wild common guillemot (Uria aalge) population found stranded at the Belgian coast.

Combined effects of heavy-metal contamination (Cu, Zn, and CH3Hg) and starvation were tested on common quails (Coturnix coturnix japonica) and used as a model for comparison with a wild common guillemot (Uria aalge) population found stranded at the Belgian coast. Appropriate heavy-metal levels were given to the quails to obtain concentrations similar to those found in the seabirds's tissues. The contaminated animals were then starved for 4 d to simulate the evident malnutrition symptoms observed at the guillemot's level. In such conditions, food intake and total-body weight are shown to decrease in contaminated individuals with simultaneous significant hepatic and renal increase of the heavy-metal concentrations. Like guillemots, higher heavy-metal levels were observed in those contam- inated quails that had also developed a cachectic status characterized by a general atrophy of their pectoral muscle and complete absence of subcutaneous and/or abdominal fat depots. Although likely the result of a general protein catabolism during starvation, it is suggested that these higher metal levels could as well enhance a general muscle wasting process (cachectic status).

Animals↗
PubMed2000

Protective effect of supplemental superoxide dismutase on survival of neuronal cells during starvation. Requirement for cytosolic distribution.

There is evidence that raising cellular levels of Cu2+/Zn2+ superoxide dismutase (SOD1) can protect neurons from oxidative injury. We compared a novel method of elevating neuronal SOD activity using a recombinant hybrid protein composed of the atoxic neuronal binding domain of tetanus toxin (C fragment or TTC) and human SOD1 (hSOD1) with increasing cellular SOD levels through overexpression. Fetal murine cortical neurons or N18-RE-105 cells were incubated with the TTC-hSOD1 hybrid protein and compared to cells constitutively expressing hSOD1 for level of SOD activity, cellular localization of hSOD1, and capacity to survive glucose and pyruvate starvation. Cells incubated with TTC-hSOD1 showed a threefold increase in cellular SOD activity over control cells. This level of increase was comparable to fetal cortical neurons from transgenic mice constitutively expressing hSOD1 and transfected N18-RE-105 cells expressing a green fluorescent protein-hSOD1 fusion protein (GFP-hSOD1). Human SOD1 was distributed diffusely throughout the cytoplasm of the transgenic murine neurons and transfected N18-RE-105 cells. In contrast, cells incubated with TTC-hSOD1 showed hSOD1 localized to the cell surface and intra-cytoplasmic vesicles. The cells expressing hSOD1 showed enhanced survival in glucose- and pyruvate-free medium. Neither cortical neurons nor N18-RE-105 cells incubated in TTC-hSOD1 showed increased survival during starvation. Access to the site where toxic superoxides are generated or their targets may be necessary for the protective function of SOD1.

Animals↗
PubMed1989

Effect of starvation on nutrition and insulin secretion in pregnant rats and their fetuses.

Pregnancy is thought to create a metabolic condition of accelerated starvation. To clarify this idea, the effect of fasting on pregnant rats (day 21 of gestation) and their fetuses was examined. Although pregnancy significantly increased plasma insulin, plasma ketone body concentrations in fed pregnant rats were higher than those of age-matched fed virgin rats. After 48 hr fasting (i.e., fasting during days 19-21 of gestation), plasma insulin was markedly decreased in virgin rats compared with term pregnant rats, while ketone bodies were significantly higher in pregnant rats than in virgin rats. Body weight was lower in fetuses from fasted mothers than those from fed mothers. Starvation also markedly diminished the insulin response to glucose in isolated, perfused pancreases in both virgin and pregnant rats. The amount of insulin released during glucose stimulation was greater in pregnancy, and the inhibitory effect of 48 hr fasting on insulin release was greater in virgin rats than in pregnant rats. It is possible, therefore, that in term pregnant rats a decrease in insulin release caused by fasting may cause more profound catabolism than in nongravid rats.

Animals↗
PubMed1980

Interrelationships between energy metabolism and thyroid hormone metabolism during starvation in the rat.

Thyroid hormone metabolism and plasma concentrations of TSH were studied after short-term hypocaloric refeeding of rats starved for 2-6 days. Carbohydrate and protein (10 kcal) refeeding after 4 days of starvation resulted in a rapid increase in serum T3 (P less than 0.01) and, less consistently of T4. Plasma TSH did not change. These findings were not due to changes in the metabolic clearance rates or in thyroid hormone binding proteins, as the disappearance of injected labelled T3 and T4, and the free fractions of T3 and T4, were unchanged. Increased thyroidal secretion, and for T3, increased peripheral conversion from T4 were therefore responsible for these changes. Fat refeeding had no immediate effect on plasma T4, T3 or TSH. After 6 days of starvation, refeeding of any nutrient was ineffective in altering the plasma concentrations of T3 and T4. The intraperitoneal administration of nicotinamide (100 mg/100 g body weight) to starving animals caused an increase in blood glucose and a decrease in blood beta-hydroxybutyrate similar to that which followed carbohydrate refeeding; T3, however, did not increase. In spite of producing a profile of substrates in the serum similar to that found following carbohydrate refeeding, nicotinamide administration had no effect on the blood lactate/pyruvate ratio which was increased following carbohydrate refeeding. Therefore, the cytoplasmic redox state, as reflected by the lactate/pyruvate ratio, may be closely related to the control of peripheral thyroid hormone metabolism.

Animals↗
PubMed1982

Effects of starvation on circadian variations of plasma TSH in rats.

Diurnal fluctuations of plasma TSH were investigated in ad libitum fed rats as well as after a 3 day starvation period in order to study the relationship between the circadian pattern of TSH secretion and nutritional status. Our study showed the persistence of a circadian TSH rhythm after a 3-day starvation without any change in the amplitude of plasma TSH variations. However, the 24 h average plasma TSH levels were significantly lower. A suggestive acrophase occurred at the same period of the day in starved and fed rats. Our results suggest that the control of plasma TSH concentrations and nycthemeral rhythm are not closely related and may even possibly be independent of one another.

Animals↗
PubMedDate not supplied

Resistance to starvation of Triatoma rubrofasciata (De Geer, 1773) under laboratory conditions (Hemiptera: Reduviidae: Triatominae).

The present work aims at learning the period of resistance to starvation (molting/death) of Triatoma rubrofasciata in different stages of development and the respective loss of weight until death. Eggs of specimens from the greater area of the city of São Luis in the State of Maranhão, Brazil, yielded approximately 300 nymphs. These nymphs were placed in labelled Borrel glasses, in which they were weekly fed on rats (Rattus norvegicus), until reaching the stage to be observed. The experiments were conducted in a climatic chamber regulated at 29 +/- 1 degrees C, 70% relative humidity and 12 hr photoperiod. The resistance to starvation increased according to the stage of development, except for adult bugs, whose results were similar to the 3rd stage nymphs. In all these development stages there was an abrupt loss of weight in the first week, followed by a gradual loss until death. Comparing this work with those of other authors, it was observed that T. rubrofasciata is among the less resistant triatomine species.

Animals↗
PubMed2001

Resistance to starvation of Rhodnius neivai Lent, 1953 (Hemiptera: Reduviidae: Triatominae) under experimental conditions.

The period of resistance to starvation and the loss of weight until death of Rhodnius neivai in all stages of development were studied. Work was based on experiments conducted under controlled laboratory conditions. One hundred specimens of each nymphal instar were observed: 50 were fed on chicken and 50 on rabbit. Adult females and males were kept together and fed on each host. All bugs were weighed weekly until death. Laid eggs were collected weekly and observed during five weeks to obtain hatchability. Resistance to starvation was similar with both hosts and increased with the evolutionary stage, excepting the 5th nymphal instar and adults. With both hosts, loss of weight was abrupt in the first week and steady in the following weeks. In adults, on the first weeks after eating, there was little or no mortality, after which mortality increased rapidly with the starving time. Reproductive output was higher in the bugs fed on rabbit. R. neivai is among the least resistant triatomine species.

Animals↗
PubMed2003

Triatoma rubrovaria (Blanchard, 1843) (Hemiptera-Reduviidae-Triatominae) III: patterns of feeding, defecation and resistance to starvation.

Data from the Chagas Disease Control Program indicate a growing domiciliary and peridomiciliary invasion of Triatoma rubrovaria in the State of Rio Grande do Sul, where it has become the most frequent triatomine species captured there since the control of T. infestans. Bionomic characteristics that could influence the vectorial capacity of T. rubrovaria as vector of Trypanosoma cruzi were evaluated: patterns of (i) feeding, (ii) defecation, and (iii) resistance to starvation, using insects fed on mice. Fifty three percent of the females showed a defecation pattern conducive to chagasic transmission, defecating either on or near the bite site. The averages of the resistance to starvation varied from 48.1 to 179 days, for the first and fifth nymphal stages, respectively. Our study shows that with respect to the patterns of feeding, defecation and resistance to fasting, T. rubrovaria presented similar rates to the ones observed for other effective vector species, such as T. infestans. Thus, based on our studies we conclude that T. rubrovaria has biological characteristics that can positively influence its capacity to become infected and transmit T. cruzi, and also to keep residual populations after chemical control interventions.

Animals↗
PubMedDate not supplied

[Survival of the mite Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) under starvation].

The ability of a natural enemy to tolerate starvation increases its chances to survive in the absence of food, what is an important factor for its success in storage grain environment. The objective of the present work was to assess the survival of Acarophenax lacunatus (Cross & Krantz) in the absence of food. The experiment used individualized physogastric females of A. lacunatus placed in petri dishes (5 cm diameter) and maintained at 20, 25, 28, 30 and 32 degrees C, 50+/-5 % R.H. and 24h scotophase. The number of live mites was recorded every 6h thus assessing the progeny survival without food at different temperatures. The mites died within 60h at the temperatures 30 degrees C and 32 degrees C, while they survived for up to 108h at 20, 25 and 28 degrees C. The mean lethal time for death was 58.6h for the lowest temperatures and 39.3h for the highest temperatures. Thus, A. lacunatus subjected to starvation lived longer under lower temperatures, what is probably due to its lower metabolism. In contrast, the mites survived for about 90h at 28 degrees C, temperature commonly observed in tropical and subtropical climates, what may favor their use as control agents of stored product insects in these regions.

Acaridae↗
PubMed1977

Effect of starvation on excretion, distribution and metabolism of DDT in mice.

Effect of starvation on tissue radioactivity of 14C-DDT was examined in mice 8 days after its single injection. Animals were completely fasted and given barium sulfate by gastric intubation for the last 3 days. The findings obtained from starved mice were as follows: 1) loss of body weight, 2) decrease in organ weight of epedidymal fat and liver, 3) reduction in lipid content of whole body as well as of epididymal fat, 4) a marked elevation of DDT levels in tissues except muscle, and 5) occasional neurotoxidc signs characterized by tremors and convulsions. Excretion of DDT-related metabolites was not changed by starvation. Analysis of metabolic producets of 14C-DDT using thin-layer radiochromatography revealed that there was little or no significant difference between control and starved mice in the metabolic pattern of DDT-related compounds in the tissues and excreta. It was assumed the DDT-ingested animals with dietary energy restriction had a subsequent risk of toxicity resulted from redistribution of DDT, but not from alteration in excretion or metabolism.

Adipose Tissue↗
PubMed1975

Physiologic mechanisms in the development of starvation ketosis in man.

The present study was undertaken to determine whether alterations in ketone body utilization and hepatic production, independent of the FFA load, were also involved in the development of fasting ketosis. Plasma Beta-OH butyric acid (Beta-OHB) increased to 2.5-4.5 mM and plasma FFA to 1,000-1,400 muEq/L. in normal weight individuals after five to seven days' starvation and in obese subjects after ten to fourteen days' fasting. Acute elevations fo the plasma FFA greater than 1,500 muEq/L. for sixty minutes in fed normal weight and obese subjects with a fat meal-heparin regimen resulted in peak elevations of plasma Beta-OHB (0.25-0.45mM), only 10 percent of that seen during fasting. When plasma FFA were lowered acutely during fasting with the antilipolytic agent Pyrazole to control levels (400-600 muEq/L.), plasma Beta-OHB decreased 35 plus or minus 5 per cent. Comparable lowering of plasma FFA in normal weight or obese starved subjects given dexamethasone to maintain elevated fasting plasma insulin levels resulted in an 87 plus or minus 3 per cent decrease in plasma Beta-OHB. Similar studies in obese fasted subjects pretreated with an intravenous infusion of insulin (1.0 U/hr. for eight hours) before receiving Pyrazole resulted in a 65 plus or minus 5 per cent decrease in plasma Beta-OHB. Plasma Beta-OHB half-life, determined after injections of 12 gm. Beta-OHB, increased significantly during fasting (110 plus or minus 15 minutes) and was decreased when the fasting subjects were maintained on dexamethasone (65 plus or minus 7 minutes). These studies indicate that accelerated hepatic ketogenesis during starvation is a result of both enhanced activity of the enzymatic system(s) involved in ketone body production as well as an increased FFA load. The increase in plasma Beta-OHB during fasting reflects not only an accelerated rate of hepatic ketogenesis but also an impairment of peripheral utilization, both processes apparently being sensitive to insulin. Diabetes 24:10-16, January, 1975.

Acidosis↗
PubMed1979

Effect of the previous diet, body weight, and duration of starvation of the assay bird on the true metabolizable energy value of corn.

Two experiments were conducted with 36 adult White Leghorn roosters to determine the effect of previous intake of protein (Experiment 1) or purified cellulose (Experiment 2), body weight, and duration of starvation of the assay bird on the true metabolizable energy (TME) value of ground yellow corn. The mean TME value (+/- SE) of the corn was 4.06 +/- .03 and 4.06 +/- .04 kcal/g of dry matter in Experiment 1 and 2, respectively. Dietary levels of 10, 20, and 30% protein or 0, 7.5, and 15.0% supplementary cellulose, and body weight distribution had no significant (P greater than .05) effect on the TME value of the corn. Starvation for 12 hr before force feeding resulted in a significant (P less than .05) decrease of 4% in the TME value of the corn, whereas fasting periods of 24 or 48 hr had no significant effect. It is suggested that the assay birds be paired on the basis of body weight and starved for a minimum period of 24 hr prior to force feeding to reduce the variation associated with the estimate of TME.

Animals↗
PubMed2001

Acid stress, starvation, and cold stress affect poststress behavior of Escherichia coli O157:H7 and nonpathogenic Escherichia coli.

The effects of acid shock, acid adaptation, starvation, and cold stress of Escherichia coli O157:H7 (ATCC 43895), an rpoS mutant (FRIK 816-3), and nonpathogenic E. coli (ATCC 25922) on poststress heat resistance and freeze-thaw resistance were investigated. Following stress, heat tolerance at 56 degrees C and freeze-thaw resistance at -20 to 21 degrees C were determined. Heat and freeze-thaw resistance of E. coli O157:H7 and nonpathogenic E. coli was enhanced after acid adaptation and starvation. Following cold stress, heat resistance of E. coli O157:H7 and nonpathogenic E. coli was decreased, while freeze-thaw resistance was increased. Heat and freeze-thaw resistance of the rpoS mutant was enhanced only after acid adaptation. Increased or decreased tolerance of acid-adapted, starved, or cold-stressed E. coli O157:H7 cells to heat or freeze-thaw processes should be considered when processing minimally processed or extended shelf-life foods.

Adaptation, Physiological↗
PubMed1982

Peripheral neuropathy and starvation after gastric partitioning for morbid obesity.

Three months after gastric partitioning for morbid obesity, two patients developed an unusual and severe form of polyneuropathy that affected their sense of position maximally. This disorder produced severe ataxia of the upper extremities and trunk, and pseudochorea. One patient died and the autopsy showed an extensive demyelinating polyneuropathy. Neuronal cell bodies in the anterior horns and dorsal root ganglia showed extensive accumulations of lipofuscin and Schwann cells showed extensive accumulations of lipid. This neuronal and Schwann cell lipidosis appears to result from starvation of the obese and has never been reported in other forms of human starvation or nutritional deficiency.

Adult↗
PubMedDate not supplied

[Effect on the whole alimentary starvation on DNA synthesis in cells precursors in human bone marrow].

The rate of DNA synthesis in cells precursors of the bone marrow of 15 psychic patients was studied by tritiated thymidine autoradiography during different periods of whole alimentary starvation (duration 28 days) which was used with the aim of therapy. It was shown that starvation induced rapid, "leap", "uneven" block of DNA synthesis and decrease in mitotic index. It was found that DNA synthesis block was marked with different degree in different marrow cells. It was supposed that DNA synthesis block occured mainly during G1--S period of interphase. During the initial period of refeeding, intensification of DNA synthesis, which preceded to sharp increase in mitotic index, was observed.

Bone Marrow↗