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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To evaluate the effects of substrate deficiency on cerebral function, metabolism, and blood flow during seizures, rats were injected intravenously with bicuculline (1.2 mg.kg-1) following a 24-hour period of starvation. During the course of seizures, blood glucose concentrations fell, and when they were reduced to below about 3 mumol.gm-1, cerebral function, metabolism, and blood flow altered. Changes in function involved the transition of an electroencephalographic pattern of bursts and suppression into one of frequent or sparse single spikes. Oxygen consumption, which initially increased at least twofold, fell toward normal or subnormal values in the single-spike period. Cortical blood flow was markedly reduced, and there was an attenuated response to carbon dioxide administration. Simultaneously, a small but clear fall was detected in the cerebral phosphorylation potential, and concentrations of glycolytic metabolites (including lactate) and citric acid cycle intermediates were reduced. Changes in amino acids and ammonia were somewhat similar to those observed in insulin-induced hypoglycemia, but since the amino acid pool did not fall, the experiments failed to give evidence that amino acids serve as oxidative substrates. The perturbation of cerebral energy state (and of levels of carbohydrate substrates and amino acids) was reversed by glucose administration; but since neither this procedure nor additional bicuculline injections could cause resumption of continuous seizure activity, the results suggest that cellular substrate depletion may have given rise to a sustained disturbance of synaptic transmission.
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PMID:Effects of bicuculline-induced seizures on cerebral metabolism and circulation of rats rendered hypoglycemic by starvation. 42 77

The effects of training to various rhythms of intermittent total starvation (ITS) or intermittent protein starvation (IPS) on the plasma glucose and the plasma insulin levels were studied in the growing chicken. Both types of feeding improved the glucose tolerance in spite of a decrease in the insulin response. After an oral glucose load, plasma free fatty acids showed opposite variations to plasma insulin and plasma glucose. The insulin released in response to a test meal was unchanged. In the ITS 1-1 group (1 day fasting-1 day feeding cycles), low glycemia-low insulinemia were observed during the fasting period of the cycle and high glycemia-hyperinsulinemia during the repletion period in response to the "adaptive hyperphagia." In the IPS 1-1 group (1 day feeding with the protein free diet-1 day feeding with the balanced diet cycles), glycemia was sustained at a high level during both periods of the cycle and insulinemia was depressed by feeding with the protein-free diet and highly stimulated by refeeding with the balanced diet. Therefore, in the chicken, intermittent feeding increases the insulin sensitivity of target tissues and modifies the B-cell sensitivity to glucose. The highest decrease in B-cell sensitivity to glucose was obtained with the protein free diet which further emphasizes the glucose-amino acid synergism previously observed for insulin release.
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PMID:Effect of intermittent feeding on glucose-insulin relationship in the chicken. 43 Feb 64

Activity of M2-pyruvate kinase from medullar layer of rabbit kidney was studied in diabetes, in starvation within 1 day and 10-16 days and in long-term starvation of rabbits after administration of glucose or hydrocortisone and protamine-Zn-insulin. The enzymatic activity was increased in diabetes and decreased in long-term starvation and after administration of insulin. A correlation was observed between low activity of pyruvate kinase in kidney medulla under conditions of long-term starvation of rabbits and deficiency of the enzyme substrate. The data, obtained after study of the enzymatic activity in kidney medulla as compared with that of rabbit kidney cortex, demonstrate various adaptability of cells from these kidney layers to regulatory effects of hormones on the pyruvate kinase activity.
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PMID:[Effect of insulin and hydrocortisone on pyruvate kinase from the medullar and cortical layers of rabbit kidney]. 44 88

The effects of starvation and of aging on the sensitivity of skeletal muscle to insulin were studied in the isolated perfused rat hindquarter preparation. As we have shown previously, starvation for 48 h had no effect on glucose uptake in hindquarters perfused with high levels of insulin (5 and 20 mU/ml). On the other hand, in the presence of physiological concentrations of insulin (50--200 muU/ml), glucose utilization was substantially greater in starved rats. Low concentrations of insulin had a greater effect on glucose uptake in fed young (100-g) than in fed older (350-g) rats. Starvation for 48 h enhanced glucose uptake in both young and older rats; however, the relative differences persisted. Starvation had similar effects on glucose utilization by the incubated soleus and extensor digitorum longus muscle. In addition, it augmented the stimulation by insulin of alpha-aminoisobutyric acid transport into the incubated extensor digitorum longus muscle. These results suggest that the in vitro sensitivity of skeletal muscle to physiological concentrations of insulin is enhanced during starvation. The basis for these findings and their physiological implications remain to be determined.
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PMID:Insulin sensitivity of rat skeletal muscle: effects of starvation and aging. 44 72

The responses of plasma gastro-entero-pancreatic (GEP) hormones and free fatty acids (FFA) to a standard mixed meal before and after starvation have been measured. Raised insulin, glucose and FFA levels were found following refeeding after starvation and levels of secretin and C-terminal glucagon-like-immunoreactivity (C-GLI), raised by starvation, were rapidly suppressed on refeeding. The responses of gastrin and N-terminal glucagon-like-immunoreactivity (N-GLI) to a standard mixed meal were not altered by starvation. Although this study does not directly support that secretin and glucagon are responsible for the hyperglycaemia or hyperinsulinaemia of starvation diabetes, a role for both hormones in the raised FFA levels is proposed, as well as a role for glucagon in the initial hyperglycaemic response to a meal after starvation.
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PMID:The gastro-entero-pancreatic hormone secretion after a mixed meal in normal subjects before and after a 72 hour period of starvation. 44 30

1. Insulin increased glucose uptake and inhibited lipolysis in white adipocytes of the rat over the same concentration range of the hormone: the half-maximal effects were observed at approx. 10 microunits of insulin/ml. Thus, contrary to previous reports, no difference in sensitivity of the two processes to insulin could be found, which suggests that both these effects of insulin are important in increasing the rate of glucose utilization after a meal. 2. Adenosine deaminase, which lowers the concentration of adenosine in the incubation medium, decreased the sensitivity of both processes (lipolysis and glucose uptake) to insulin: this suggests that adenosine increases the sensitivity of both processes. Similarly, lactate and 3-hydroxybutyrate increased the sensitivity of both processes (to the same extent) to insulin. It is suggested that this increased sensitivity will improve the response (of adipose tissue) to insulin on refeeding after a prolonged period of starvation (when the hydroxybutyrate concentration is high), and after a short burst of exercise, when the blood lactate concentration is high and when large amounts of glucose are produced from lactate via gluconeogenesis in the liver.
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PMID:Sensitivity of glucose uptake and lipolysis of white adipocytes of the rat to insulin and effects of some metabolites. 48 14

In order to determine the endocrine and metabolic state of thyrotoxicosis we measured blood glucose and plasma insulin response to ingestion of a mixed meal in 19 euthyroid and 9 hyperthyroid subjects. Moreover concentrations of glucose, free fatty acids (FFA), glycerol, acetoacetate (AcAc) beta-hydroxybutyrate (beta-OHB), insulin and human growth hormone (hGH) were determined in the blood of both healthy and hyperthyroid patients after an overnight and a 39-h fast. In another group of thyrotoxics the overnight fasting respiratory quotient (RQ) was measured. After a mixed meal blood glucose and plasma insulin changes of FFA, AcAc and beta-OHB was significantly higher in thyrotoxics, whereas hGH increase did not appear significantly greater in these subjects. There was no statistical difference between the respiratory quotient mean values found in hyperthyroid and in control subjects. In conclusion, these data indicate that in thyrotoxicosis absolute insulin response to a mixed meal is normal and that food deprivation considerably increase lipid mobilization from adipose tissue and causes an exaggerated starvation ketosis. The RQ mean valoue suggests that in the hyperthyroid state lipid-derived fuel as well as carbohydrate-derived fuel contributes to the increased oxygen consumption.
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PMID:Studies on metabolic alterations after a mixed meal and during a 39-hour fast in thyrotoxicosis. 48 28

1. GPAT (glycerol phosphate acyltransferase) and DHAPAT (dihydroxyacetone phosphate acyltransferase) activities were measured both in subcellular fractions prepared from fed rat liver and in whole homogenates prepared from freeze-stopped pieces of liver. 2. GPAT activity in mitochondria differed from the microsomal activity in that it was insensitive to N-ethylmaleimide, had a higher affinity towards the palmitoyl-CoA substrate and showed a different response to changes in hormonal and dietary status. 3. Starvation (48 h) significantly decreased mitochondrial GPAT activity. The ratio of mitochondrial to microsomal activities was also significantly decreased. The microsomal activity was unaffected by starvation, except after adrenalectomy, when it was significantly decreased. Mitochondrial GPAT activity was decreased by adrenalectomy in both fed and starved animals. 4. Acute administration of anti-insulin serum significantly decreased mitochondrial GPAT activity after 60 min without affecting the microsomal activity. 5. A new assay is described for DHAPAT. The subcellular distribution of this enzyme differed from that of GPAT. The highest specific activity of DHAPAT was found in a 23 000 gav. pellet obtained by centrifugation of a post-mitochondrial supernatant. This fraction also contained the highest specific activity of the peroxisomal marker uricase. DHAPAT activity in mitochondrial fractions or in the 23 000 gav. pellet was stimulated by N-ethylmaleimide, whereas that in microsomal fractions was slightly inhibited by this reagent. The GPAT and DHAPAT activities in mitochondrial fractions had a considerably higher affinity for the palmitoyl-CoA substrate. 6. Total liver DHAPAT activity was significantly decreased by starvation (48 h), but was unaffected by administration of anti-insulin serum. 7. The specific activities of GPAT and DHAPAT were lower in non-parenchymal cells compared with parenchymal cells, but the GPAT/DHAPAT ratio was 5--6-fold higher in the parenchymal cells.
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PMID:A study of the glycerol phosphate acyltransferase and dihydroxyacetone phosphate acyltransferase activities in rat liver mitochondrial and microsomal fractions. Relative distribution in parenchymal and non-parenchymal cells, effects of N-ethylmaleimide, palmitoyl-coenzyme A concentration, starvation, adrenalectomy and anti-insulin serum treatment. 51 62

Chronic alcoholism is a frequently unrecognized cause of ketoacidosis in nondiabetic patients. Seven episodes of alcoholic ketoacidosis were observed in three patients. No consciousness disturbances were present. Semi-quantitative tests for ketones were strongly positive in urine, weakly positive in serum. The anion gap was between 25 and 41 mEq/l; serum lactate was between 0.9 and 9.0 mEq/l, and, in all cases, below the anion excess. Blood glucose ammonia was increased. Massive fatty liver was documented in all patients. All ketosis episodes followed an increase of alcohol ingestion associated with one to four week-starvation and vomiting; however, at the time of admission, alcohol was weakly increased in blood. In the four episodes where diagnosis was correct, ketoacidosis was rapidly corrected without insulin administration. In conclusion, in some nondiabetic subjects, the occurence of alcohol prolongated ingestion together with starvation and vomiting is responsible for ketoacidosis; because alcoholic ketoacidosis has often a mild clinical expression, its true prevalence is underestimated; insulin administration is not required.
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PMID:[Alcoholic ketoacidosis (author's transl)]. 53 15

1. Although high concentrations of insulin affect both synthesis and degradation of skeletal-muscle protein, it is not known to what extent these effects occur with physiological concentrations. The effects of a physiological concentration of insulin (100 mu units/ml) on muscle protein synthesis, measured with [3H]tyrosine, and on muscle protein degradation, measured by tyrosine release in the presence of cycloheximide, were studied in mouse soleus and extensor digitorum longus muscles in vitro. 2. Insulin significantly stimualated protein synthesis in both muscles, but an inhibition of degradation was seen only in the extensor digitorum longus. 3. Starvation for 24 h decreased the rate of protein synthesis and increased the rate of breakdown in the extensor digitorum longus. Sensitivity to insulin-stimulation of proteins synthesis in the soleus was increased by starvation. 4. ;a 20%-surface-area full-skin-thickness dorsal scald injury produced a fall in total protein content in soleus and extensor digitorum muscles, maximal on the third day after injury. Soleus muscles 2 days after injury showed an impairment of protein synthesis; degradation was unaffected and neither synthesis nor degradation in vitro was significantly affected in the extensor digitorum longus. 5. The advantages and limitations of studies of protein metabolism in vitro are discussed.
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PMID:Regulation of protein metabolism by a physiological concentration of insulin in mouse soleus and extensor digitorum longus muscles. Effects of starvation and scald injury. 53 31


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