Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine running performance and hormonal and metabolic responses during insulin-induced hypoglycemia, fed and fasted male rats (315 +/- 3 g) were infused with insulin (100 mU/ml, 1.5 ml/h) or saline (1.5 ml/h) for 60 min and then killed at rest or after running on the treadmill (21 m/min, 15% grade). Insulin-infused fed rats ran poorly during the second 10 min of a 20-min exercise test. They were capable of running a total of 43 +/- 5 min, compared with 138 +/- 6 min for saline-infused fed rats. Fasted insulin-infused rats were able to run only 12.8 +/- 0.8 min, compared with 122 +/- 15 min for fasted saline-infused rats. In fasted rats, blood glucose was 1.6 +/- 0.1 mM after 60 min of insulin infusion and 1.2 +/- 0.1 mM after running to exhaustion. Artificial increase of plasma free fatty acids had no effect on performance. Intravenous infusion of glucose at the time of fatigue produced an immediate recovery, allowing the formerly fatigued rats to run 20 min without development of fatigue. These results provide evidence that severe hypoglycemia can be a significant cause of fatigue, even if it occurs early in the course of an exercise bout.
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PMID:Insulin-induced hypoglycemia in fed and fasted exercising rats. 160 10

Using the mixed type musculus latissimus dorsi of the dog in the present work, we show the effect of carnitine on an in situ fatigue test. L-Carnitine appears to improve force of this muscle by 34% while stimulated in situ. This effect of carnitine is acute and (stereo)specific, since neither D-carnitine nor the structural analogue choline (also a tertiary amine) has a positive effect on contractile force. Because skeletal muscle is rich in carnitine and because carnitine transport is slow, its effect must be exerted outside the striated muscle cells. Insulin (with glucose) administration abolished the carnitine effect. It is speculated that facilitation of fatty acid oxidation in the blood vessel wall is the basis for this positive effect of carnitine.
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PMID:Acute effect of L-carnitine on skeletal muscle force tests in dogs. 199 22

Fifty-nine patients with both clinical evidence of thyroid dysfunction and patent diabetes mellitus were investigated in our diabetology department. Patients with euthyroid goitre and iatrogenic or pituitary hypothyroidism were excluded from the study. Among the 45 diabetics with hyperthyroidism, 32 had Graves' disease and 13 had toxic adenoma; 71% were insulin-treated. Hyperthyroidism had passed unnoticed in 7 of these 32 patients because fatigue and loss of weight, which initially were the predominant or sole symptoms, are extremely frequent in uncontrolled diabetes. These symptoms, as well as polyuria, polyphagia and even sweating are common to both diseases. Considerable deterioration in the control of glycaemia was observed in 63% of the insulin-treated patients when hyperthyroidism developed, with a 17 to 212% (mean 82%) increase in insulin dosage in 53%. There was no correlation between the degree of hyperthyroidism and the loss of control. Following treatment of the hyperthyroidism, control was improved in 63%, with an 11-83% (mean 44%) decrease in insulin dosage in 59% of them. Insulin therapy could be withdrawn in only one of the 32 insulin-treated patients. Non-iatrogenic primary hypothyroidism was found in 0.2% of the diabetics investigated. This incidence was significantly higher than the calculated probability of the two diseases occurring by chance in the same patient. Eleven out of 14 patients were insulin-treated. When hypothyroidism developed, 73% of them had their insulin dosage reduced, with a high frequency of hypoglycaemic disorders: repeated "malaise" in 55% and coma in 27%. A higher proportion of vitiligo was also noted: 14% in the total patient population reported, and 18% in insulin-treated patients.
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PMID:[Effect of clinical hyperthyroidism and hypothyroidism on patent diabetes. 59 cases]. 315 40

Denervated (1-10 days) rat epitrochlearis muscles were isolated, and basal and insulin-stimulated protein and glucose metabolism were studied. Although basal rates of glycolysis and glucose transport were increased in 1-10-day-denervated muscles, basal glycogen-synthesis rates were unaltered and glycogen concentrations were decreased. Basal rates of protein degradation and synthesis were increased in 1-10-day-denervated muscles. The increase in degradation was greater than that in synthesis, resulting in muscle atrophy. Increased rates of proteolysis and glycolysis were accompanied by elevated release rates of leucine, alanine, glutamate, pyruvate and lactate from 3-10-day-denervated muscles. ATP and phosphocreatine were decreased in 3-10-day-denervated muscles. Insulin resistance of glycogen synthesis occurred in 1-10-day denervated muscles. Insulin-stimulated glycolysis and glucose transport were inhibited by day 3 of denervation, and recovered by day 10. Inhibition of insulin-stimulated protein synthesis was observed only in 3-day-denervated muscles, whereas regulation by insulin of net proteolysis was unaffected in 1-10-day-denervated muscles. Thus the results demonstrate enhanced glycolysis, proteolysis and protein synthesis, and decreased energy stores, in denervated muscle. They further suggest a defect in insulin's action on protein synthesis in denervated muscles as well as on glucose metabolism. However, the lack of concurrent changes in all insulin-sensitive pathways and the absence of insulin-resistance for proteolysis suggest multiple and specific cellular defects in insulin's action in denervated muscle.
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PMID:Resistance of protein and glucose metabolism to insulin in denervated rat muscle. 319 84

Progressive weight loss and anorexia are frequent phenomena in cancer patients. Although cachexia is an expected occurrence in the terminal stages of nearly all malignancies, it may be a presenting sign when the tumor burden is quite small. Lipid depletion occurs out of proportion to the protein loss and accounts for most of the weight loss in cancer. Lipids, more specifically fatty acids, are the major source of fuel in mammals and may also be used in the synthesis of new cell products. Lipolysis and lipogenesis are under the influence of several important enzymes and peptide hormones that may be modulated by a variety of exogenous factors. There is evidence that cancer patients have lost the normal homeostatic responses to decreased energy intake or starvation that allow a decrease in oxygen consumption and protein sparing. An increase in Cori cycle activity or futile recycling of metabolic products occurs with a net energy expenditure rather than energy production. Clinical studies have shown that the body lipid depletion accompanying tumor progression is not solely secondary to decreased food intake and may be reproduced by the transplantation of certain noninvasive tumors to normal hosts. Elevated basal lipolysis has occasionally been seen early in tumor growth. Such findings suggest the presence of a tumor-associated factor responsible for this increase in lipid mobilization. Some of the potential mechanisms for the altered lipid metabolism seen in cancer have been discussed. Metabolic substrates may be remodeled and directed away from fuel-efficient into energy-requiring pathways. An increased energy expenditure may occur as a result of the energy costs of tumor synthesis, an uncoupling of oxidative phosphorylation, or energy-requiring futile cycling. An overall depletion of lipid may be the final outcome of the inhibition of lipid deposition. TNF/cachectin has recently been found to suppress the activity and synthesis of several key lipogenic enzymes, including lipoprotein lipase. Abnormalities in insulin secretion or sensitivity may be involved in the decrease of fat storage in malignancy. Insulin also exerts a significant antilipolytic effect by its antagonism of hormone-sensitive lipase. Mediators of lipolysis and abnormal lipid metabolism may occur in a number of clinical conditions and include ectopic hormone production, growth factors, and tumor-associated lipolytic factors (lipid mobilizing factor, toxohormone).
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PMID:Fat metabolism and cancer. 353 75

The urinary excretion of 3-methylhistidine has been determined in rats fed an energy-depleted diet. Young male rats were fed over a 21-day period on either an adequate control diet (18% lactalbumin), or an energy-depleted diet (containing half of the amount of carbohydrates of the control diet). Urinary urea-N, creatinine, creatine and 3-methylhistidine, as well as body weight changes were monitored throughout the experiment. At the end of the experiment, the levels of insulin and corticosterone, and the weights of livers and gastrocnemius, soleus, tibialis anterior and extensor digitorum longus muscles were determined. A significant (p less than 0.05) reduction in body and liver weight was found in the energy-depleted rats, but no weight differences were found in the four excised muscles. Urinary outputs of urea-N, creatine and creatinine were significantly (p less than 0.05) increased in this latter group. Output of 3-methylhistidine showed an initial rise followed by a significant (p less than 0.05) and progressive decline throughout the experiment in the rats fed the energy deficient diet. Insulin concentration was significantly (p less than 0.01) reduced in those animals, but no differences were found in the serum levels of corticosterone. It is assumed that lack of energy in the diet decreases the rate of myofibrillar protein breakdown in growing rats.
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PMID:Muscle protein breakdown in young rats fed on a energy-depleted diet. 701 47

The purpose of this study was to document the self-care behaviors of patients with type I diabetes, identify their concerns about having diabetes, and measure their level of control (HbA1c). A 20-point questionnaire was mailed to 105 young adults with type I diabetes. Fifty-nine (56%) returned the questionnaire (33 males, mean age 23.2 years; 26 females, mean age 22.7 years). Duration of diabetes was 5 months to 25 years (mean = 11.28 years). HbA1c range was 5% to 13.9% (mean = 7.85%, normal < 6.6%). Sixty-eight percent performed at least one blood glucose test per day and 12% reported not testing at all. The number of insulin injections per day ranged from 2 to 5, and 83% regularly adjusted their insulin dose. Confidence in adjusting insulin was not related to duration of diabetes, age, or sex. Insulin manipulation to control weight was reported by 38% (24 females, 2 males). The long-term complications they were concerned about were eye disease (35%), pregnancy and childbirth (27%), hypoglycemia (13%), and loss of independence (5%). Hypoglycemia was always recognized by 35%, although 50% sometimes confused it with stress, tiredness, and high blood glucose. All subjects reported that hypoglycemia affected their lifestyle.
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PMID:Young-adult perspectives of insulin-dependent diabetes. 783 6

The objective of this study was to investigate the existence of abnormalities of insulin sensitivity in patients with chronic heart failure. Glucose metabolism and insulin resistance were assessed in 10 male patients with severe, chronic heart failure and in 10 matched control subjects. Glucose, insulin and C-peptide concentration profiles were measured following a 0.5 g.kg-1 intravenous glucose tolerance test. Insulin sensitivity (inversely related to insulin resistance) was estimated by minimal modelling analysis of the glucose and insulin profiles. Heart failure patients had similar mean fasting plasma glucose concentration to controls but a significantly greater mean fasting plasma insulin concentration (P = 0.002) and C-peptide concentration (P = 0.02). Plasma glucose response profile was similar in the two groups but the incremental plasma insulin response profile of the heart failure group was significantly greater (P = 0.004). Mean insulin sensitivity was 73% lower in the heart failure patients (P = 0.003). These findings show that patients with severe chronic heart failure are hyperinsulinaemic and insulin resistant compared with a matched health group. This insulin resistance and hyperinsulinaemia may contribute to the progressive deterioration in myocardial function and associated clinical features of fatigue and reduced exercise tolerance seen in heart failure. Interventions designed to overcome or reduce insulin resistance warrant further investigation.
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PMID:Insulin resistance in chronic heart failure. 783 69

The bioenergetic effects of cancer cachexia on the livers of male Fischer rats inoculated with a methylcholanthrene-induced sarcoma were assessed using serial in vivo 31P magnetic resonance spectroscopy. Rats were randomized into three groups: tumor-bearing controls (n = 7); an insulin-treated group receiving 2 units/100 g body weight/day starting 21 days after implantation (n = 8); and a chronic insulin-treated group receiving insulin every day after implantation (n = 3). During the 32-day study, serial measurements of food intake, body weight, and tumor volume were taken, and 31P magnetic resonance spectroscopy analyses of the livers were conducted every 7 days after tumor implantation. Neither the short-term nor the chronic insulin treatment regimens stimulated the progress of tumor growth. However, both treatments prevented body weight loss, and the short-term insulin treatment prevented tumor-induced decrease in food intake relative to the control group. Liver bioenergetic deterioration was evaluated from the increase in the ratio of Pi to ATP obtained from the hepatic 31P magnetic resonance spectra. At day 28 postimplantation, control rats exhibited appreciable hepatic bioenergetic deterioration, i.e., a Pi/ATP ratio of 1.41 +/- 0.35 (SE), significantly higher (P < 0.05) than the Pi/ATP ratio for short-term or chronic insulin treatment groups (Pi/ATP 0.92 +/- 0.22 and 0.84 +/- 0.22, respectively) or rats before tumor implantation (Pi/ATP 0.76 +/- 0.14). This insulin-induced bioenergetic protection occurred at any given tumor burden up to at least 10%. Thus, both short-term insulin given just prior to the frank manifestations of cancer cachexia and chronic insulin treatment given throughout tumor growth ameliorated host hepatic bioenergetic deterioration without significantly stimulating tumor growth. Insulin may act by altering the host metabolism (stimulation of liver glucose uptake and utilization, decreased energy-requiring gluconeogenesis, and general protein-sparing action) at the expense of the tumor.
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PMID:Insulin protects against hepatic bioenergetic deterioration induced by cancer cachexia: an in vivo 31P magnetic resonance spectroscopy study. 798 32

Patients with noninsulin-dependent diabetes mellitus (NIDDM) are often obese and frequently complain of tiredness. These features are also characteristically seen in patients with obstructive sleep apnea (OSA). Therefore, it was the aim of this study to assess the prevalence of OSA among a group of obese NIDDM patients who have some clinical features of OSA. The effect of reversal of OSA by nasal continuous positive airway pressure (CPAP) treatment on insulin responsiveness was also investigated. From a population of 179 NIDDM patients with a body mass index (BMI) greater than 35 kg/m2, we performed ambulatory sleep monitoring on 31 (15 males and 16 females) who admitted to either heavy snoring or excessive sleepiness. Results were reviewed by a sleep physician blinded to the clinical status of the patients, and 22 (70%) were found to have moderate or severe OSA, with mean oxygen desaturation indexes of 10.3 +/- 5.3 and 30.7 +/- 13.2 episodes/h, respectively. A subgroup of 10 patients (seven males and three females) with a mean BMI of 42.7 +/- 4.3 kg/m2 was treated with nightly CPAP for 4 months. These subjects all had significant OSA, with frequent obstructive apneas (mean, 47 +/- 31.6 episodes/h) and oxygen desaturation (mean minimum O2 saturation, 74 +/- 9.5%), as determined by polysomnography. One patient was excluded from analysis because of infrequent use of CPAP. Insulin responsiveness in terms of glucose disposal measured by hyperinsulinemic euglycemic clamps improved from 11.4 +/- 6.2 to 15.1 +/- 4.6 mumol/kg.min (P < 0.05) during CPAP treatment. These results indicate that OSA occurs commonly in obese NIDDM patients with excessive sleepiness or heavy snoring. Treatment of their OSA may improve insulin responsiveness.
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PMID:Obstructive sleep apnea in obese noninsulin-dependent diabetic patients: effect of continuous positive airway pressure treatment on insulin responsiveness. 798 75


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