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PubMed1992

Alterations in protein kinase C system of colonic epithelium during fasting-refeeding. Evidence for protein kinase C independent pathway of enhanced proliferative activity.

In the present study, we compared (1) incorporation of [3H]dThd into DNA, (2) total protein kinase C (PKC) activity, (3) the subcellular distribution of PKC, and (4) PKC isozyme (alpha, beta and gamma) mass in colonic mucosal scrapings and isolated superficial and proliferative colonic epithelial cells from 48-hr fasted, 48-hr fasted-refed, and ad libitum-fed rats. Total colonic mucosal PKC activity and PKC alpha mass were higher and the in vivo rate of [3H]dThd incorporation into mucosal DNA was markedly depressed in 48-hr fasted rats compared to ad libitum-fed or fasted-refed rats. These alterations were localized predominantly to the proliferative pool of colonic epithelial cells. Despite an 11-fold increase in mucosal DNA synthesis, no alterations in total mucosal PKC activity were detected in fasted-refed rats compared to rats fed ad libitum. Moreover, no differences in the subcellular distribution of PKC were noted among any of the dietary groups. Intrarectal instillation of deoxycholate activated PKC and increased DNA synthesis 1.5- to 2-fold. Deoxycholate-induced increases in DNA synthesis, but not those induced by refeeding, were inhibited by treatment of rats with the PKC inhibitors H-7, sphingosine, or staurospaurine. The results do not support a role for PKC in the mediation of increased proliferative activity of colonic mucosa induced by refeeding.

Analysis of Variance↗
PubMed1997

Distribution of prohormone convertase-6 expression in the gastrointestinal tract and effects of a fasting-refeeding regimen and a high-fat diet on ileal prohormone convertase-6 expression.

Proforms of gastrointestinal peptide hormones and neuropeptides are processed, in part, by prohormone convertases (PCs) to mature, biologically active peptides. The purpose of this study was to characterize the mRNA levels of PC-6 isoforms, PC-6A and PC-6B, in the gastrointestinal tract and pancreas of the rat, and to investigate the effects of a fasting and refeeding regimen, and a high-fat diet on ileal PC-6A expression. PC-6A mRNA is expressed throughout the entire gastrointestinal tract with the highest levels in the small intestine. Multiple-sized transcripts are present. PC-6B mRNA is expressed in the antrum and fundus of the stomach, in the small intestine, and colon. Ileal PC-6A mRNA expression increases significantly with fasting and then declines with refeeding toward control levels. Increased dietary fat increases PC-6A mRNA levels in the ileum. Since PC-6 is found throughout the entire gastrointestinal tract, it is likely that PC-6 participates in the processing of proforms of gastrointestinal peptides. The two isoforms of PC-6 have different patterns of distribution in the gastrointestinal tract and pancreas, suggesting that they process proforms of different gut peptides.

Animals↗
PubMed2005

Immediate postoperative refeeding in orthopedic surgery is safe.

The purpose of this retrospective study was to investigate the morbidity of immediate postoperative refeeding after orthopedic surgery. We included all the 1077 patients who underwent orthopedic surgery between January and December 2003 at our military teaching hospital. General anesthesia was performed in 37% of the patients (n = 398), 24% (n = 259) had combined general and regional anesthesia, and 39% (n = 420) had isolated regional anesthesia (spinal anesthesia and/or peripheral regional anesthesia). After surgery, each patient was allowed free access to solid and liquid food immediately after discharge from the postanesthetic care unit. Although no systematic nausea and vomiting prophylaxis was performed, only 7% (n = 75) of the patients had postoperative nausea and vomiting during the first 48 h. Moreover, neither deglutition trouble nor aspiration syndrome was observed during that period. Our results suggest that immediate postoperative refeeding after orthopedic surgery is safe, does not increase postoperative nausea and vomiting, and probably increases the comfort of patients.

Anesthesia↗
PubMed1991

Control of urea synthesis and ammonia utilization in protein deprivation and refeeding.

Rats were fed a standard diet (20% protein) or a protein-free diet for up to 65 days. After 20 days on the protein-free diet some rats were refed the standard diet. By the 20th day the rats fed the protein-free diet showed a blood ammonia level approximately 70% higher than controls and urea excretion decreased approximately 20-fold. At this time the liver acetylglutamate decreased to approximately one-fifth of the initial and control levels, returning to normal after 3 days of refeeding the standard diet, with a concomitant increase in urea excretion. The protein-deficient diet resulted in decreased activities of liver enzymes related to ammonia metabolism. All enzyme activities assayed returned to normal values rapidly upon refeeding the standard diet, except hepatic carbamylphosphate synthetase, glutamine synthetase, and glutaminase, which took approximately 1 month to return to control values. The findings presented here are consistent with the view that urea production is controlled, at least under certain conditions, by acetylglutamate, the physiological activator of carbamylphosphate synthetase.

Ammonia↗
PubMed1986

Fasting and refeeding modulate neutral amino acid transport activity in the basolateral membrane of the rat exocrine pancreatic epithelium: fasting-induced insulin insensitivity.

The effects of fasting and refeeding on amino acid transport in the perfused rat exocrine pancreas were investigated using a rapid dual tracer dilution technique. Unidirectional amino acid influx (15 s) was quantified (relative to the extracellular tracer D-mannitol) over a wide range of perfusate concentrations in pancreata isolated frm fed and 24 h, 48 h, and 72 h fasted and 72 h fasted and refed (24 h) animals. In fed animals transport of phenylalanine (1-24 mM) and L-serine (1-50 mM) was saturable and weighted non-linear regression analyses of the overall transport indicated an apparent Kt = 10 +/- 3 mM and Vmax = 7.0 +/- 1.0 mumol/min per g (n = 7) for phenylalanine and Kt = 16 +/- 3 mM and Vmax = 20.6 +/- 2.1 mumol/min per g (n = 5) for serine. Fasting animals for 24 h or 48 h did not change the kinetics of either phenylalanine or serine transport. After a 72 h fast the rate of phenylalanine transport (Vmax = 15.9 +/- 2.9 mumol/min per g, n = 5) was enhanced whereas the transport affinity (Kt = 11 +/- 3 mM) remained unaltered. L-Serine transport was essentially unaltered. When 72 h fasted animals were refed for 24 h the Vmax for phenylalanine transport was reduced to values observed in fed animals. In parallel experiments refeeding had no significant effect on serine transport. Perfusion of pancreata isolated from 72 h fasted animals with bovine insulin (1 mU/ml or 1 microU/ml) did not stimulate either phenylalanine or serine transport.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1991

Regulation of rat antral gastrin and somatostatin gene expression during starvation and after refeeding.

Antral gastrin and somatostatin gene expression during starvation and after refeeding with liquid meals of varying composition were studied. Northern and slot-blot hybridization analyses showed that starvation caused a marked decrease in antral gastrin messenger RNA (mRNA) level by 12 hours associated with an increase in somatostatin mRNA. After 48 hours of fasting, antral gastrin mRNA was 26% and somatostatin mRNA was 136% of their prefasting levels. Refeeding caused increased 2-hour integrated gastrin mRNA levels after liquid peptone (+45%), phenylalanine (+31%), and olive oil (+13%), but no changes were observed with glucose or saline solutions. Integrated 2-hour immunoreactive antral gastrin content was increased after peptone (+106%), phenylalanine (+68%), and olive oil (+32%) meals but was not increased after glucose (-11%) or saline (-10%). In some cases, both gastrin mRNA and peptide responses could be measured as early as 15 minutes. The same nutrients that increased gastrin mRNA levels caused decreased 2-hour integrated somatostatin mRNA levels; peptone (-30%), phenylalanine (-28%), and olive oil (-21%), but neither glucose nor saline, altered somatostatin mRNA levels. These results suggest that antral gastrin and somatostatin genes were regulated in opposite directions, in a coordinate manner, by specific gastric nutrients that stimulate gastrin release.

Animals↗
PubMed1985

RNA polymerase activities and chromatin protein composition of rat liver during methionine deprivation and refeeding.

The reversible effect of dietary methionine deficiency was studied in young adult rats. The sensitivity of nuclear chromatin to micrococcal nuclease (EC3.1.4.7) digestion and the composition of the chromatin proteins were unaffected by the dietary regimens. The specific chromatin-bound RNA polymerase II activity decreased during methionine deficiency. Refeeding of methionine for 2 days restored the activity in the nuclease-released chromatin. RNA polymerase I plus III activity remained unchanged. Total RNA polymerase activity changed with the liver wet weight which was reduced during methionine deficiency and was not restored to control level after 2 days of methionine refeeding. RNA polymerase activity was altered by methionine deficiency. The recovery was independent of major modifications of the chromatin structure and protein composition.

Animals↗
PubMed1984

The effect of different kinds of refeeding on islet glucose phosphorylating activities.

The aim of the present work has been to study the regulating effect of different kinds of diet on the activities of enzymes that phosphorylates glucose into glucose 6 phosphate in the islets of Langerhans. The metabolism of glucose in the B cell is controlled by two different enzymes, hexokinase and glucokinase, whose activities are lowered during fasting; this coincides with lowered levels of blood glucose and blood insulin and with a blocking of the insulin-secretory response toward glucose. Refeeding with a high-carbohydrate diet restores glucokinase activity in islet extracts, blood insulin, and blood glucose. By contrast, refeeding with a low-carbohydrate diet restores hexokinase activity in islet extracts, restores poorly blood insulin, and is unable to unblock the insulin secretory response toward glucose. These results support the important role that glucokinase plays in the regulation of glycolytic flux and on insulin secretion in the B cell. Hexokinase could play a role in the regulation of the glycolytic flux when the B cell responds to other secretagogues.

Animals↗
PubMed1985

Supplemental essential amino acids augment the somatomedin-C/insulin-like growth factor I response to refeeding after fasting.

Plasma somatomedin-C (Sm-C)/insulin-like growth factor I (IGF-I) concentrations have been shown to reflect changes in nitrogen balance induced by manipulation of nutrient intake. To assess the Sm-C/IGF-I response to refeeding a protein restricted diet in which the nitrogen source was supplemented with essential amino acids, six normal adults were fasted for five days, then refed for nine days diets consisting of 35 kcals/kg and 0.48 g protein/kg body weight. In one diet, 80% of the nitrogen was supplied as essential amino acids, and in the other, 80% was supplied as nonessential amino acids. Following the first fast/refeed cycle, a control diet was eaten for two weeks before the fast was repeated and the other test diet was ingested. The refeeding diets were given a random order. Plasma Sm-C/IGF-I fell from a pre-fast mean of 1.64 +/- 0.24 U/mL (mean +/- 1 SEM) to 0.67 +/- 0.18 (P less than 0.001) following fasting, and rose to 1.41 +/- 0.19 U/mL (P less than 0.001) following ingestion of the diet with supplemental essential amino acids. In contrast, when the same subjects were refed a diet in which 80% of the nitrogen was in the form of nonessential amino acids, the plasma Sm-C/IGF-I concentrations rose from 0.74 +/- 0.17 to 1.15 +/- 0.15 U/mL (P less than 0.01). This increase was significantly less than that observed after ingestion of the essential amino acid supplemented diet (0.74 +/- 0.10 U/mL v 0.40 +/- 0.11 U/mL; P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Effect of carbohydrate refeeding on free fatty acids after a fast in obese diabetic and obese non-diabetic females.

The metabolic effects of refeeding with oral or intravenous carbohydrate were studied in obese women after ten or 14 days of fasting. Seven patients were refed with protein-free fruit juice for a total of 250 g of carbohydrate (1,000 kcal) over ten hours. The juice was sipped continuously throughout this time, causing a drop in free fatty acids (FFA) from 1.07 +/- 0.08 to 0.61 +/- 0.05 mmol/L (P less than .01) over the first four hours. Over the next four hours, despite continuous ingestion of the carbohydrate and elevated plasma glucose (132 +/- 9 mg/dL) and insulin (2.81 +/- 0.86 ng/mL) (1 ng/mL = 25 microU/mL), FFA rose to 0.99 mmol/L (P less than .01). Similar results were obtained in five patients refed with similar amounts of oral glucose and four patients who received an equivalent amount of glucose intravenously (IV). Refeeding with carbohydrate of obese diabetic and non-diabetic women after a two-week fast caused an abrupt decrease in FFA that was followed after four hours by an increase in FFA and glycerol, despite continued ingestion of carbohydrate glucose and insulin.

3-Hydroxybutyric Acid↗
PubMed1992

Effects of fasting, refeeding, and fasting with T3 administration on Na-K,ATPase in rat skeletal muscle.

It is known that Na-K,adenosine triphosphatase (ATPase) in cell membranes represents an important consumer of cellular energy, eg, adenosine triphosphate (ATP), and that the concentration and activity of this enzyme change in a dose-dependent manner with serum thyroid hormone levels. To examine the hypothesis that low triiodothyronine (T3) syndrome represents a cellular adaptation in generalized severe illnesses that saves tissue energy expenditure, we measured the muscle Na-K,ATPase concentration and its activity in rats that led to low T3 syndrome induced by fasting. The Na-K,ATPase concentration was measured by 3H-ouabain binding to soleus muscle, and its activity was measured by 42K uptake in the contralateral soleus muscle. The effects of refeeding or T3 administration on Na-K,ATPase in soleus muscle in fasted rats were also examined. Na-K,ATPase concentration and activity were both increased in hyperthyroid rats and decreased in hypothyroid rats. In the fasting state, they were decreased to as low as the levels seen in hypothyroidism. Furthermore, with fasting + refeeding or fasting + T3 administration, Na-K,ATPase in soleus muscle returned to the normal level. These results suggest that tissue energy expenditure, as assessed by Na-K,ATPase, in skeletal muscles of fasted rats with low T3 syndrome is actually decreased to levels seen in hypothyroidism, due at least partly to the decrease in serum T3 concentrations, and that there exist some adaptation mechanisms in the peripheral tissues for the accommodation of energy metabolism in the body through decreased thyroxine (T4) to T3 conversion.

Adenosine Triphosphate↗
PubMed1992

Na+/K(+)-ATPase activity and its alpha II subunit gene expression in rat skeletal muscle: influence of diabetes, fasting, and refeeding.

We have examined the effects of diabetes, fasting, and refeeding on Na+/K(+)-adenosine triphosphatase (ATPase) activity and its catalytic alpha II subunit gene expression in skeletal muscle. Two hypoinsulinemic states, streptozotocin-induced diabetes and 48-hour fasting caused a significant decrease (P less than .05) in skeletal muscle Na+/K(+)-ATPase activity and a marked increase (P less than .01) in the levels of alpha II subunit mRNA. A decrease in enzyme activity was observed on the 2nd and the 14th day of diabetes, whereas an increase in alpha II mRNA levels was found only on the 14th day. The levels of alpha I mRNA were not affected, while the levels of mRNA of the structural beta subunit were decreased on the 14th day of diabetes. Correction of hyperglycemia with insulin restored enzyme activity and alpha II isoform mRNA levels toward normal in diabetic animals. Refeeding for 48 or 72 hours restored these parameters to normal in skeletal muscle of previously fasting rats. These observations suggest that a decrease in muscle Na+/K(+)-ATPase activity may lead to a compensatory increase in its alpha II subunit gene expression. The levels of insulin and not of glycemia appear to be critical in modulating Na+/K(+)-ATPase activity and gene expression.

Animals↗
PubMed1993

Effect of meal pattern during food restriction on body weight loss and recovery after refeeding.

The present study was designed to assess whether the pattern of meal feeding and the degree of caloric restriction have an effect on the body weights and refeeding patterns of restricted 4-month-old Long-Evans rats, relative to ad lib-fed controls. Four experimental groups of rats (n = 6 each) were put on different paradigms of food restriction, and a fifth group fed ad lib throughout served as controls. Twelve rats were restricted to receiving 50% of their mean baseline food intake, and 12 rats received only 70% of their baseline food intake. Each experimental group was further subdivided with one subgroup receiving all of their calories in one meal/day and the other with caloric intake equally divided into two meals/day. There was no statistical difference in the final body weights of the restricted groups. Although there appeared to be identical patterns of weight regain, none of the restricted groups ever reached the mean body weight of the controls because of an asymptotic leveling off of rate of body weight regain. Rats that had received 50% of baseline calories as two meals/day had significantly more adipose mass than did any other group. The present findings suggest that in the rat, refeeding and, hence, regulation, occurs to normalize rate of weight gain rather than absolute body weight.

Animals↗
PubMed1995

Refeeding in fasted rats: dietary self-selection according to metabolic status.

We investigated the influence of the metabolic status rats have reached during a fast on their selection of protein, fat and carbohydrate when allowed to refeed after fasting for different lengths of time. They were refed either while essentially relying on lipid fuels (group 1), or while in the further stage when there is a rise in protein breakdown (group 2). In contrast to previous studies in which rats could not select macronutrients, there was no transitory anorexia during refeeding. Macronutrient selection as well as food and energy intake on the first day of refeeding were the same for both groups, total food intake being significantly larger than prior to the fast. However, there was thereafter a distinct pattern of diet selection: while fat intake progressively decreased in group 1, it increased until the fifth day in rats of groups 2. These rats, moreover, exhibited a further rise in protein intake. The data are discussed in relation to the optimization of the restoration of body fuel reserves according to the metabolic status reached at the end of a long fast.

Animals↗
PubMed1996

Refeeding after prolonged fasting in rats: nycthemeral variations in dietary self-selection.

The influence of metabolic status on food selection during refeeding after fasting was investigated in rats fasted for a long period of time and subsequently given the choice of eating fat, protein, and carbohydrate individually. Rats were fasted until either metabolic phase 2 (essentially using lipids) or metabolic phase 3 (when there was a rise in protein utilization). The very large first meal of the refeeding was identical in the two groups of animals and consisted mainly of fat and protein. The observed diurnal hyperphagia persisted for 2 days in phase 2, while in phase 3 the hyperphagia persisted throughout the 8 observation days. Both periods of hyperphagia consisted of an increase in fat and in protein intakes. The nocturnal intake was increased, but to a lesser extent, on days 4 and 5 in phase 2 and on days 4, 5, and 6 in phase 3. These results can be related to the metabolic events present during the diurnal part of the nycthemeral cycle.

Animals↗
PubMed1980

Molluscum contagiosum and herpes simplex in Maasai pastoralists; refeeding activation of virus infection following famine?

An epidemic of molluscum contagiosum and oro-genital herpes simplex was observed in Maasai pastoralists of the Rift Valley. It coincided with a period of refeeding following famine, when the relief diet was different from normal milk fare. We propose that refeeding may be an important mechanism for activation of certain viral infections previously suppressed by famine.

Adolescent↗