Persistence of metabolic rhythmicity during fasting and its entrainment by restricted feeding schedules in rats

1998 ◽  
Vol 274 (5) ◽  
pp. R1309-R1316 ◽  
Author(s):  
Carolina Escobar ◽  
Mauricio Díaz-Muñoz ◽  
Fabiola Encinas ◽  
Raúl Aguilar-Roblero
Keyword(s):  
Fatty Acids ◽  
Lipid Metabolism ◽  
Free Fatty Acids ◽  
Ketone Bodies ◽  
Liver Glycogen ◽  
Restricted Feeding ◽  
Feeding Schedule ◽  
Daily Food ◽  
Catabolic State

The presence of a food-entrainable oscillator (FEO) independent from the SCN is now well established, but until now its location and characterization have been elusive. Because its expression requires priming of the animal’s metabolism toward a catabolic state, it is possible that metabolic rhythms may be related to FEO. The present study was designed to determine whether metabolic rhythms persist during fasting and whether such rhythms could be entrained to a restricted feeding schedule. The results indicate persistent rhythms of triacylglycerides, free fatty acids, glucose, and proteins during fasting, whereas ketone bodies and liver glycogen changed their concentration as a function of fasting. Daily food pulses of 2 h entrained the rhythms of triacylglycerides and free fatty acids and restored ketone bodies and liver glycogen to similar levels as controls. Neither glucose nor proteins were affected by the food pulse. These results indicate the relevance of lipid metabolism as a phenomenon associated with the FEO.

scholarly journals Effects of 3-hydroxybutyrate and free fatty acids on muscle protein kinetics and signaling during LPS-induced inflammation in humans: anticatabolic impact of ketone bodies

2018 ◽  
Vol 108 (4) ◽  
pp. 857-867 ◽  
Author(s):  
Henrik H Thomsen ◽  
Nikolaj Rittig ◽  
Mogens Johannsen ◽  
Andreas B Møller ◽  
Jens Otto Jørgensen ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Acute Inflammation ◽  
Ketone Bodies ◽  
Muscle Protein ◽  
Initiation Factor ◽  
Whole Body ◽  
Protein Breakdown ◽  
Protein Kinetics ◽  
Nonesterified Fatty Acids

Abstract Background Acute inflammation, and subsequent release of bacterial products (e.g. LPS), inflammatory cytokines, and stress hormones, is catabolic, and the loss of lean body mass predicts morbidity and mortality. Lipid intermediates may reduce protein loss, but the roles of free fatty acids (FFAs) and ketone bodies during acute inflammation are unclear. Objective We aimed to test whether infusions of 3-hydroxybutyrate (3OHB), FFAs, and saline reduce protein catabolism during exposure to LPS and Acipimox (to restrict and control endogenous lipolysis). Design A total of 10 healthy male subjects were randomly tested 3 times, with: 1) LPS, Acipimox (Olbetam) and saline, 2) LPS, Acipimox, and nonesterified fatty acids (Intralipid), and 3) LPS, Acipimox, and 3OHB, during a 5-h basal period and a 2-h hyperinsulinemic, euglycemic clamp. Labeled phenylalanine, tyrosine, and urea tracers were used to estimate protein kinetics, and muscle biopsies were taken for Western blot analysis of protein metabolic signaling. Results 3OHB infusion increased 3OHB concentrations (P < 0.0005) to 3.5 mM and decreased whole-body phenylalanine-to-tyrosine degradation. Basal and insulin-stimulated net forearm phenylalanine release decreased by >70% (P < 0.005), with both appearance and phenylalanine disappearance being profoundly decreased. Phosphorylation of eukaryotic initiation factor 2α at Ser51 was increased in skeletal muscle, and S6 kinase phosphorylation at Ser235/236 tended (P = 0.074) to be decreased with 3OHB infusion (suggesting inhibition of protein synthesis), whereas no detectable effects were seen on markers of protein breakdown. Lipid infusion did not affect phenylalanine kinetics, and insulin sensitivity was unaffected by interventions. Conclusion During acute inflammation, 3OHB has potent anticatabolic actions in muscle and at the whole-body level; in muscle, reduction of protein breakdown overrides inhibition of synthesis. This trial was registered at clinicaltrials.gov as NCT01752348.

scholarly journals A Clinical Case of Clozapine-Induced Fatal Diabetic Ketoacidosis

2016 ◽  
Vol 7 ◽  
pp. CMPsy.S30532
Author(s):  
Eric Romney ◽  
Vinay J. Nagaraj ◽  
Amie Kafer
Keyword(s):  
Fatty Acids ◽  
Weight Gain ◽  
Free Fatty Acids ◽  
Diabetic Ketoacidosis ◽  
Ketone Bodies ◽  
Pancreatic Beta Cell ◽  
Metabolic Effects ◽  
Psychotic Symptoms ◽  
Life Threatening ◽  
Altered Metabolism

Introduction Clozapine, a second generation medication, has become the atypical antipsychotic drug of choice for refractory or treatment-resistant schizophrenia. In addition to the high risk of agranulocytosis and seizures, clozapine treatment is increasingly associated with significant metabolic effects, such as hyperglycemia, central weight gain and adiposity, hypertriglyceridemia, and elevated low-density lipoprotein cholesterol. A potentially life-threatening complication of altered metabolism is diabetic ketoacidosis (DKA). This report details a case of fatal DKA in a schizophrenic patient undergoing treatment with clozapine. Case Description An African–American male in his 20s with a medical history significant for schizophrenia was presented to the psychiatric inpatient ward with severe paranoid thoughts and aggressive behavior. After trials of risperidone, olanzapine, and haloperidol—all of which failed to adequately control his psychotic symptoms—clozapine titration was initiated and he showed significant improvement. Weight gain was observed throughout hospitalization, but all blood and urine test results showed no metabolic or hematological abnormalities. The patient was discharged for outpatient treatment on clozapine (125 mg morning and 325 mg evening) along with divalproex sodium and metoprolol. Six days post-discharge, the patient died. A medical autopsy later ruled that the death was due to DKA without any evidence of contributory injuries or natural disease. Results and Conclusion Significant increase in body mass index from 28.7 to 33.5 was observed during hospitalization. The blood glucose level, measured after his death, was found to be 500 mg/dL. Altered metabolism due to clozapine can lead to dyslipidemia-mediated-pancreatic-beta-cell damage, decreased insulin secretion as well as insulin resistance. In DKA, low levels of insulin lead to an increased release of free fatty acids from adipose tissue. Acetyl coenzyme A (CoA), derived from the breakdown of free fatty acids, is metabolized by the Kreb's cycle. In hepatocytes, excess acetyl-CoA is converted into ketone bodies (acetoacetate and β-hydroxybutyrate) and released into circulation. Ketone bodies have a low p Ka value and their high serum concentrations lead to DKA. In this patient, DKA was most probably clozapine induced and had fatal consequences. Thus, recognizing potential risk factors, providing patient education, and increasing monitoring of patients on clozapine and other atypical antipsychotics are critical to prevent the life-threatening effects of DKA.

Metabolic concomitants of hypophagia during recovery from insulin-induced obesity in rats

1983 ◽  
Vol 245 (3) ◽  
pp. E211-E219 ◽  
Author(s):  
I. Ramirez ◽  
M. I. Friedman
Keyword(s):  
Fatty Acids ◽  
Weight Loss ◽  
Food Intake ◽  
Free Fatty Acids ◽  
Insulin Treatment ◽  
Liver Glycogen ◽  
Diabetic Rats ◽  
Acid Oxidation ◽  
Hepatic Fatty Acid Oxidation ◽  
Adipose Tissue Lipoprotein Lipase

Rats were given daily injections of protamine-zinc insulin (PZI) that increased food intake and body weight. Termination of insulin treatment resulted in transient hypophagia and weight loss. Simultaneously with the weight loss, plasma levels of glycerol, free fatty acids, glucose, and ketones increased, whereas adipose tissue lipoprotein lipase activity and liver glycogen decreased. These changes in food intake and metabolism after termination of PZI treatment were accentuated in streptozotocin-diabetic rats. Two antilipolytic drugs (nicotinic acid and 3,5-dimethylpyrazole) blocked the elevation in plasma glycerol while having no effect on food intake. A 1-day fast after termination of insulin treatment equalized insulin-treated and control groups for plasma glycerol and ketones and reversed group differences in free fatty acids; the elevation in plasma glucose persisted despite starvation. Following starvation, previously PZI-treated rats ate less than controls on refeeding. The results show that enhanced lipolysis does not invariably accompany hypophagia during excess weight loss and suggest that a disturbance in carbohydrate metabolism or an increase in hepatic fatty acid oxidation may underlie this decrease in food intake.

scholarly journals Free Fatty Acids Impair FGF21 Action in HepG2 Cells

2015 ◽  
Vol 37 (5) ◽  
pp. 1767-1778 ◽  
Author(s):  
Mohamed Asrih ◽  
Christophe Montessuit ◽  
Jacques Philippe ◽  
François R. Jornayvaz
Keyword(s):  
Gene Expression ◽  
Fatty Acids ◽  
Lipid Metabolism ◽  
Free Fatty Acids ◽  
Hepg2 Cells ◽  
Lipid Lowering ◽  
Fibroblast Growth Factor 21 ◽  
Beneficial Effects ◽  
Positive Effects

Background/Aims: Fibroblast growth factor 21 (FGF21) is a key mediator of glucose and lipid metabolism. However, the beneficial effects of exogenous FGF21 administration are attenuated in obese animals and humans with elevated levels of circulating free fatty acids (FFA). Methods: We investigated in vitro how FFA impact FGF21 effects on hepatic lipid metabolism. Results: In the absence of FFA, FGF21 reduced lipogenesis and increased lipid oxidation in HepG2 cells. Inhibition of lipogenesis was associated with a down regulation of SREBP-1c, FAS and SCD1. The lipid-lowering effect was associated with AMPK and ACC phosphorylation, and up regulation of CPT-1α expression. Further, FGF21 treatment reduced TNFα gene expression, suggesting a beneficial action of FGF21 on inflammation. In contrast, the addition of FFA abolished the positive effects of FGF21 on lipid metabolism. Conclusion: In the absence of FFA, FGF21 improves lipid metabolism in HepG2 cells and reduces the inflammatory cytokine TNFα. However, under high levels of FFA, FGF21 action on lipid metabolism and TNFα gene expression is impaired. Therefore, FFA impair FGF21 action in HepG2 cells potentially through TNFα.

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