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

Prolonged starvation is known to induce significant alterations in several cardiac lysosomal enzymes, particularly the acid proteinase cathepsin D. To determine what specific factors might mediate these changes, fetal mouse hearts in organ culture were maintained in media designed to simulate selected hormonal or nutritional substrate changes that accompany starvation. Reduced concentrations of glucose caused an increase in the activity of beta-acetylglucosaminidase but had no effect on cathepsin D or acid phosphatase activites (i.e., effects opposite from those of starvation). Also, high concentrations of free fatty acid, acetoacetate, and beta-OH-butyrate induced an increase in cathepsin D (+18%) and a simultaneous decrease in glucosaminidase (-19%), with little change in acid phosphatase. Furthermore, glucagon had no effect on any of the enzymes, whereas growth hormone caused a small (6%) increase in cathepsin D activity. In addition, insulin deprivation caused significant increases (7-25%) in the activities of all three enzymes. Insulin deprivation and excess ketones, but not the other interventions, increased the proportion of enzyme activity which was nonsedimentable. These results suggest the possibility that lysosomal alterations during starvation may be related in part to prolonged insulin deficiency and exposure to high concentrations of ketones and free fatty acids.
Circ Res 1976 Sep
PMID:Hormonal and nutritional substrate control of cardiac lysosomal enzyme activities. 95 75

The stimulatory effect of starvation on omega oxidation of stearate by the 20,000 X g supernatant fluid of rat liver homogenates was studied. The effect was obtained after starvation for 24 hours. Starvation for longer times did not further increase omega oxidation. The stimulatory effect of starvation on omega oxidation of stearic acid was accompanied by a reduced incorporation of stearic acid into phosphatidic acid, diglycerides, and triglycerides. Substitution of the 100,000 X g supernatant fluid from liver homogenate of starved rats with 100,000 X g supernatant fluid from liver homogenates of control rats reduced the microsomal omega oxidation of stearic acid with a simultaneous increase in incorporation of stearic acid into the different glycerides. Under the latter conditions almost no free stearic acid could be isolated from the incubation mixture after the incubation. Of three different soluble factors necessary for glyceride formation, ATP appeared to be the most important from a regulatory point of view. Thus the soluble fraction of liver homogenate from a starved rat was shown to contain suboptimal concentrations of ATP. Addition of physiological amounts of ATP to the 20,000 X g supernatant fluid of homogenate of liver of starved rats had the same effect as addition of 100, 000 X g supernatant fluid from liver homogenate of control rats, i.e. decrease in omega oxidation and increase in formation of glycerides. Addition of sn-glycerol 3-phosphate and CoA-SH in amounts optimal for glyceride formation to the 20,000 X g supernatant fluid of liver homogenate of starved rats had only small effects on omega oxidation and glyceride formation. The results are consistent with a competition for free fatty acids between the acyl-CoA synthetases involved in biosynthesis of glycerides and the microsomal hydroxylase(s) involved in omega oxidation of fatty acids. The concentration of ATP in the soluble fraction is of importance in this competition. The possibility is discussed that this competition is of importance also under in vivo conditions and that a decreased rate of esterification in the starved state is responsible for the higher excretion of omega-oxidized fatty acids in urine in the ketotic state.
J Biol Chem 1976 Sep 10
PMID:On the mechanism of regulation of omega oxidation of fatty acids. 95 85

The effects of starvation, an 800-kcal mixed diet and an 800-kcal ketogenic (low carbohydrate-high fat) diet on the composition of weight lost were determined in each of six obese subjects during three 10-day periods. The energy-nitrogen balance method was used to quantify the three measurable components of weight loss; protein, fat, and water. On the 800-kcal ketogenic diet, subjects lost (mean +/- SE) 466.6 +/-51.3 g/day; on the isocaloric mixed diet, which provided carbohydrate and fat in conventional proportions, they lost 277.9+/- 32.1 g/day. Composition of weight lost (percentage) during the ketogenic diet was water 61.2, fat 35.0, protein 3.8. During the mixed diet, composition of loss was water 37.1, fat 59.5, protein 3.4...
J Clin Invest 1976 Sep
PMID:Composition of weight lost during short-term weight reduction. Metabolic responses of obese subjects to starvation and low-calorie ketogenic and nonketogenic diets. 95 98

It has been shown that the net rate of gluconeogenesis from cysteine was only 10% the rate observed from pyruvate. This suggested that the rate limiting step in gluconeogenesis from cysteine was between cysteine and pyruvate. Evidence is presented showing that the cysteine-sulfinate pathway does not play a regulating role in the conversion of cysteine to glucose. Thus, liver cysteine desulfhydrase (CDS) activity and hydrogen sulfide production were evaluated for their potential effects. Liver CDS activity was increased by a 3 day starvation, by feeding a 90% casein diet or a 4% cysteine + 86% casein diet. In all cases the activity of the enzyme was in excess of that required to account for the rate of conversion of cysteine to glucose observed, thus the potential activity of this enzyme was not a rate limiting factor. The possible effect of H2S, an end product of the CDS reaction, on gluconeogenesis from cysteine was evaluated. The addition of NaHS abolished the glucogenic response observed from cysteine, but had very little effect on glucoeogenesis from lactate, suggesting that accumulated H2S may inhibit CDS, marking CDS rate limiting in the conversion of cysteine to pyruvate.
J Nutr 1976 Sep
PMID:Fractors affecting the rate of gluconeogenesis from L-cysteine in the perfused rat liver. 95 11

Fat cells isolated from rat epididymal adipose tissue were incubated with albumin-bound [14C]palmitate. Incorporation of 14C into 14CO2 and glycerides was measured. Some evidence is presented to suggest that the exogenous palmitate pool is in isotopic equilibrium with intracellular precursors for these metabolic processes. Precautions were taken to minimize dilution of the exogenous palmitate pool by fatty acids released from the cells. 14CO2 production from [1-14C]palmitate was 3 times that from [16-14C]palmitate. Octanoate increased this differential oxidation of palmitate carbons and also inhibited palmitate oxidation without similarly affecting esterification. Glucose increases palmitate esterification in cells from fed or starved rats. Insulin potentiated this effect of glucose. Glucose influenced palmitate oxidation in a more complex manner, dependent upon the glucose concentration. Both the observation that esterification constitutes 99% of the metabolic flux of fatty acid and the manner in which glucose, insulin, or starvation influence palmitate esterification and oxidation suggested that factors controlling esterification may alter oxidation as a secondary effect, but not vice versa. It is suggested that oxidation and esterification compete for a single intracellular precursor, possibly extramitochondrial long chain fatty acyl CoA.
J Lipid Res 1976 Sep
PMID:Factors affecting fatty acid oxidation in fat cells isolated from rat white adipose tissue. 96 42

The effect of pre-operative starvation, anaesthesia and surgery on blood sugar levels and the handling of carbohydrate load during operation were studied in 28 Nigerian children between 2 months and 15 years of age. (1) Age and body weight were important factors influencing the relationship between duration of pre-operative fast and the pre-induction blood sugar level in children. Hypoglycaemic values occurred in 7 per cent of the subjects studied although none was clinically hypoglycaemic. (2) Halothane anaesthesia alone did not affect blood sugar levels but relaxant anaesthesia in this study caused significant rise of blood sugar. (3) There was a marked hyperglycaemic response to surgery and handling of glucose load during operation was significantly poorer than before operation.
Can Anaesth Soc J 1976 Sep
PMID:Effect of anaesthesia and surgery on blood sugar and carbohydrate tolerance in African children. 97 57

Water deprivation for 48 hr with its accompanying decrease in food intake significantly lowered the in vitro rate of hexobarbital metabolism by hepatic microsomes isolated from male rats. Pair-fed rats allowed water ad libitum had a significantly lower level of hexobarbital metabolism than those deprived of water. Rats starved for 24 hr with or without water also had levels of hexobarbital metabolism significantly lower than their controls; with those animals allowed water ad libitum, the level was significantly lower than for those deprived of water. In vivo hexobarbital "sleeping time" experiments were in general agreement with these results. The in vitro metabolism of aniline was increased in both male and female rats following 24 hr starvation and in female rats (but not males) the effect was greater when water was allowed than when deprived. The differences between hydrated and dehydrated animals were not attributable to reduction in concentration of microsomal protein or the water content of liver. It is concluded that water consumption accentuates the effect of food deprivation on hepatic microsomal metabolism.
J Toxicol Environ Health 1976 Sep
PMID:Effect of water and food deprivation on hepatic microsomal metabolism of hexobarbital and aniline. 99 38

Experiments were conducted to investigate plasma free amino acid concentrations in the chick. After one hour of fasting, total plasma amino acid concentration decreased to approximately half of the full-fed value. Within three to six hours, most amino acids had returned toward the full-fed level but did not exceed it throughout a 48 hour period of starvation. However, after 48 hours fasting lysine, threonine, and isoleucine accumulated three-fold, two-fold and two-fold of the full-fed level, respectively. Serine and glutamic acid exceeded the full-fed level at three hours and then declined. Alanine reached its highest level after six hours of fasting and then declined. In full-fed chicks diurnal variations of plasma free amino acid concentrations were observed. The lowest and highest concentrations were observed at 11 a.m. and 8 to 11 p.m., respectively under a 24 hr-lighting. Reference plasma amino acid patterns are reported for chicks fed a practical diet ad libitum. In day-old chicks, concentrations of total amino acids, methionine plus one half cystine, lysine, and arginine were high. Alanine and glutamic acid concentrations were low. Most amino acid concentrations declined gradually during the first four weeks of life, but methionine plus one half cystine, phenylalaine, threonine and serine concentrations decreased sharply between two and four weeks. Lysine concentration continued to decrease in chicks fed the starter diet. At 20 weeks, plasma amino acid concentrations had decreased considerably except for methionine plus one half cystine and basic amino acids. The plasma amino acid pattern for chicks fed an isolated soybean protein diet was similar to that of chicks fed the practical diet.
Poult Sci 1976 Sep
PMID:Conditions affecting plasma amino acid patterns in chickens fed practical and purified diets. 103 38

Ethanol elimination rates were determined in rats using an intravenous route of ethanol administration after several experimental manipulations. Twenty-four hr food deprivation resulted in a 30% reduction to 35 mg/100ml blood/hr in elimination rate from a non-deprived rate of 50 mg/100 ml blood/hr. After 2 months of ethanol drinking (5% v/v), 24 hr starvation resulted in only a 10% reduction in elimination rate (45 mg/100 ml blood/hr), and did not increase the non-food-deprived rate (49.2 mg/100 ml blood/hr) over that obtained in the above animals' drinking water rather than 5% ethanol. Animals which chronically overdrank ethanol or water for 3 months on a schedule-induced polydipsia procedure, known to result in ethanol physical dependence, showed a decreased rate of ethanol elimination (37.9 mg/100 ml blood/hr for water drinkers) in the non-food-deprived condition. By providing 750 mg of liver powder daily as a food supplement in the ethanol overdrinking regimen, the ethanol elimination rate remained at a rate comparable to the normal animal (48.4 mg/100 ml blood/hr).
Pharmacol Biochem Behav 1976 Sep
PMID:Ethanol elimination rates in normal and ethanol dependent animals. 103 70

Starvation of strains of Escherichia coli which are glycerol auxotrophs and are also defective in beta oxidation results in the accumulation of large amounts of free fatty acid (Cronan, J. E., Jr., Weisberg, L. W., and Allen, R. G. (1975) J. Biol. Chem. 250, 5835-5840). We now report that the ratio of saturated to unsaturated species appearing in the free fatty acid fraction depends on the incubation temperature at the time of synthesis of these acids. This result indicates that fatty acid synthesis is one site of the thermal control of phospholipid fatty acid composition. We also report experiments on the incorporation of exogenously supplied fatty acids into membrane phospholipids. The effect of temperature on this incorporation supports the hypothesis that a second site of thermal regulation acts at the level of phosphatidic acid synthesis.
J Biol Chem 1975 Sep 10
PMID:Thermal regulation of the membrane lipid composition of Escherichia coli. Evidence for the direct control of fatty acid synthesis. 109 1


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