Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Lipid Mobilization”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources
PubMed2006

Temporal dynamics of 1H-NMR-visible metabolites during radiation-induced apoptosis in MG-63 human osteosarcoma spheroids.

The metabolic changes that occur as a function of time in MG-63 osteosarcoma three-dimensional tumor spheroids undergoing radiation-induced apoptosis were studied using high-resolution proton nuclear magnetic resonance ((1)H-NMR) spectroscopy. Specifically, the (1)H-NMR spectra of MG-63 spheroids collected at 24, 48 and 72 h after exposure to 5 Gy of ionizing radiation were compared to the spectra of their respective controls. Small spheroids (about 50-80 microm in diameter) with no hypoxic center were used. Apoptosis was verified by both staining of spheroid DNA with the Hoechst 33258 dye and determination of caspase 3 enzyme activity at the three times examined. The results demonstrate that, as the percentage of apoptosis rises with time after exposure to ionizing radiation, the metabolic changes that take place in MG-63 spheroids follow very precise temporal dynamics. In particular, significant time-related increases in both CH(2) and CH(3) mobile lipids, considered by many authors as markers of apoptosis, were observed. In addition, temporal variations were also observed in choline-containing metabolites, reduced glutathione (GSH), glutamine/glutamate, taurine, alanine, creatine/phosphocreatine and lactate. These data show that in addition to CH(2) and CH(3) lipids, other metabolites can also be extremely useful in a deeper understanding of the temporal dynamics of radiation-induced apoptosis. This comprehension is particularly important in spheroids, a cell model of great complexity that resembles in vivo tumors much more closely than monolayer cultures. Ultimately, it is hoped that such studies can help to evaluate the outcome of radiotherapy protocols more accurately.

Apoptosis↗
PubMed1997

Trehalose inhibits the release of adipokinetic hormones from the corpus cardiacum in the African migratory locust, Locusta migratoria, at the level of the adipokinetic cells.

The effect of trehalose at various concentrations on the release of adipokinetic hormones (AKHs) from the adipokinetic cells in the glandular part of the corpus cardiacum of Locusta migratoria was studied in vitro. Pools of five corpora cardiaca or pools of five glandular parts of corpora cardiaca were incubated in a medium containing different concentrations of trehalose in the absence or presence of AKH-release-inducing agents. It was demonstrated that trehalose inhibits spontaneous release of AKH I in a dose-dependent manner. At a concentration of 80 mM, which is the concentration found in the hemolymph at rest, trehalose significantly decreased the release of AKH I induced by 100 microM locustatachykinin 1, 10 microM 3-isobutyl-1-methylxanthine (IBMX) or high potassium concentrations. The specificity of the effect of trehalose was studied by incubating pools of corpora cardiaca with the non-hydrolyzable disaccharide sucrose or with glucose, the degradation product of trehalose, both in the presence and absence of 10 microM IBMX. Sucrose had no effect at all on the release of AKH I, whereas glucose strongly inhibited its release. The results point to the inhibitory effect of trehalose on the release of AKH I being exerted, at least partly, at the level of the adipokinetic cells, possibly after its conversion into glucose. The data presented in this study support the hypothesis that in vivo the relatively high concentration of trehalose (80 mM) at rest strongly inhibits the release of AKHs. At the onset of flight, the demand for energy substrates exceeds the amount of trehalose that can be mobilized from the fat body and consequently the trehalose concentration in the hemolymph decreases. This relieves the inhibitory effect of trehalose on the release of AKHs, which in turn mobilize lipids from the fat body.

Animals↗
PubMed2000

The Effect of sex steroid hormones on substrate oxidation during prolonged submaximal exercise in women.

In animals, female sex steroid hormones (SS, estrogens-progesterone) influence the energy substrate that is metabolized. Human research on this issue is controversial. This study examined whether changes in circulating SS hormone levels affected the carbohydrate-lipid metabolism during submaximal prolonged (60 min) exercise. Young, physically active females were studied. Four were classified as anovulatory-oligomenorrheic and four were classified as ovulatory-eumenorrheic. Subject responses were pooled to form one group (n = 8) and then their responses under low (L) and high (H) pharmaceutically manipulated SS hormone conditions were examined. During exercise, the mean oxygen consumption levels were 1.70 +/- 0.10/ x min(-1) for L-SS and 1.75 +/- 0.11/ x min(-1) for H-SS (p = 0.07), respectively. The respiratory exchange ratio (RER) responses were significantly different during exercise between the conditions: 0.93 +/- 0.04 for L-SS and 0.90 +/- 0.04 for H-SS (p < 0.05), respectively. RER responses were utilized to calculate substrate oxidation. Significantly less carbohydrate oxidation was found in the H-SS condition as compared to the L-SS condition (p < 0.05). Lipid oxidation was also significantly different, but for this measure, the levels of oxidation were greater in the H-SS than in the L-SS condition (p < 0.05). Finally, total energy expenditure for the 60 min of exercise was not significantly different between the hormonal conditions. Results suggest that sex steroid hormones have an impact upon substrate oxidation in women during exercise. Specifically, high circulating concentrations of the SS hormones result in an enhanced reliance upon the oxidation of lipid as an energy substrate and consequently induce a reduction in carbohydrate oxidation. The mechanism inducing this "metabolism shift" appears due to sex steroid hormones directly and indirectly increasing lipid mobilization and lipolysis.

Adult↗
PubMed2005

Caveolin-1 expression is essential for proper nonshivering thermogenesis in brown adipose tissue.

Recently, we have shown that loss of caveolin-1 leads to marked alterations in insulin signaling and lipolysis in white adipose tissue. However, little is known about the role of caveolin-1 in brown adipose tissue (BAT), a tissue responsible for nonshivering thermogenesis. Here, we show that caveolin-1 null mice have a mildly, yet significantly, decreased resting core body temperature. To investigate this in detail, we next subjected the mice to fasting (for 24 h) or cold treatment (4 degrees C for 24 h), individually or in combination. Interestingly, caveolin-1 null mice showed markedly decreased body temperatures in response to fasting or fasting/cold treatment; however, cold treatment alone had no effect. In addition, under these conditions caveolin-1 null mice failed to show the normal increase in serum nonesterified fatty acids induced by fasting or fasting/cold treatment, suggesting that these mice are unable to liberate triglyceride stores for heat production. In accordance with these results, the triglyceride content of BAT was reduced nearly 10-fold in wild-type mice after fasting/cold treatment, but it was reduced only 3-fold in caveolin-1 null mice. Finally, electron microscopy of adipose tissue revealed dramatic perturbations in the mitochondria of caveolin-1 null interscapular brown adipocytes. Taken together, our data provide the first molecular genetic evidence that caveolin-1 plays a critical functional and structural role in the modulation of thermogenesis via an effect on lipid mobilization.

Adipose Tissue, Brown↗
PubMed1997

Effect of number of pig embryos in the uterus on their survival and development and on maternal metabolism.

The effects of pig embryo number on fetal survival and growth and maternal metabolism were evaluated with 114 Large White gilts. Gilts were assigned at 38 kg to three treatments: control (CTR), ligature of the left oviduct (LIG), or right hemi-hysteroovariectomy (HHO). Insemination occurred at 311 +/- 18 d of age. A laparotomy was performed at d 35 of gestation, and gilts were slaughtered at d 112. Ovulation rate per uterine horn was 4.30, 8.70, and 17.12 in the LIG, CTR, and HHO groups, respectively. The hierarchy was the same for litter size at d 35 of gestation, but the relative differences were reduced (3.24, 5.98, and 8.40 fetuses/uterine horn, respectively). Litter size per uterine horn was similar in the CTR and HHO groups at d 112 of pregnancy (2.93, 4.69, and 4.76 fetuses in the LIG, CTR, and HHO groups, respectively). Early (before d 35 of gestation), late, and total fetal mortality increased with embryo potential per uterine horn. There was a compensation between early and late fetal mortality in the CTR and HHO groups. Fetal weight at d 112 was related to litter size in early pregnancy (1.50, 1.38, and 1.27 kg in the LIG, CTR, and HHO groups, respectively). Uterine capacity limits litter size and fetal development, even in sows with a conventional potential of embryos. Availability of energetic and gluconeogenic substrates was higher at 110 than at 60 d of gestation in the three groups. Blood substrate levels suggested that lipid mobilization and glucose uptake were higher in the gilts with a larger litter weight.

Alanine↗
PubMed1981

The influence of sow dietary lipids and choline on piglet survival, milk and carcass composition.

Twenty-one crossbred gilts and 75 crossbred sows were randomly assigned to six treatments for examination of the effect of lipid feeding and choline level on baby pig survival. Dietary variables were supplemental fat and choline in a 3 X 2 factorial arrangement. Fat treatments were no supplemental fat, 10% corn oil and 10% animal fat; choline treatments were 0 and 500 ppm supplemental choline from choline chloride. Baby pig survival and litter weight at 21 days were improved (P less than .05) by supplemental fat. Lipid treatments also improved (P less than .05) percentage survival among piglets in the weight ranges of 909 g or less, 1,136 to 1,362 g and 1,363 to 1,589 grams. Lipid feeding increased survival by 18.5% among the piglets weighing less than 909 grams. Piglets fasted for 60 hr had 47.7% less (P less than .05) total lipids and 90.5% less (P less than .05) glycogen than 12-hr-old, nonfasted piglets. The feeding of corn oil significantly affected percentages of carcass fatty acids. Percentages of palmitic, palmitoleic, oleic and linoleic acids decreased during fasting, indicating good utilization, while percentages of stearic and arachidonic acids increased, indicating poorer utilization during fasting. Milk from control sows, which had received a gestation diet containing 4% added poultry fat prior to treatment, was only slightly lower in energy and lipid content (nonsignificant) than milk from sows on the lipid treatment. Corn oil affected (P less than .05) the percentage of fatty acids in milk. Additional choline appeared to have no beneficial effect in any phase of the experiment. Choline did not increase lipid mobilization or piglet survival.

Animals↗
PubMed1984

Inositol as a lipotropic agent in dairy cattle diets.

Fatty liver syndrome or hepatic lipidosis (HL) is a condition thought to contribute to an increased incidence of peripartum disease, reduced response to therapy and decreased fertility in dairy cows. This syndrome is characterized by excess triglyceride (TG) accumulation in the liver and apparent decreased hepatic lipoprotein output. In lactating rats, a similar condition results from feeding an inositol-deficient diet. It is also characterized by excess hepatic TG accumulation and decreased hepatic lipoprotein output. Myo-inositol is a necessary component of the phospholipid phosphatidyl-inositol, which is an important membrane constituent. Myo-inositol occurs in feed mainly as the inositol hexaphosphate phytic acid. Phytic acid is undigestible by the monogastric but rumen phytases are assumed to adequately hydrolyze it. In early lactation dairy cows, lipid mobilization is intense, and the myo-inositol requirement may exceed the dietary supply or availability. Myo-inositol is being tested in a field trial as a potential lipotropic agent for dairy cows. Preliminary results suggest no lipotropic benefit from added myo-inositol.

Animals↗
PubMed2004

[Pathogenesis and treatment of cancer anorexia-cachexia, with special emphasis on aged patients].

Cachexia is among the most debilitating and life-threatening aspects of cancer and is more common in children and elderly patients. Associated with anorexia, fat and muscle tissue wasting, psychological distress, and a lower quality of life, cachexia arises from a complex interaction between the cancer and the host. This process results from a failure of the adaptive feeding response seen in simple starvation and includes cytokine production, release of lipid-mobilizing and proteolysis-inducing factors, and alterations in intermediary metabolism. Cytokines play a pivotal role in long-term inhibition of feeding by mimicking the hypothalamic effect of excessive negative feedback signaling from leptin, a hormone secreted by adipose tissue, which is an integral component of the homeostatic loop of body weight regulation. This could be caused by persistent inhibition of the feeding-stimulatory circuitry including neuropeptide Y. Cachexia should be suspected in patients with cancer if an involuntary weight loss of greater than five percent of premorbid weight occurs within a 3-6-month period. The two major options for pharmacological therapy have been either progestational agents or corticosteroids. However, knowledge of the mechanisms of cancer anorexia-cachexia syndrome has led to, and continues to lead to, effective therapeutic interventions for several aspects of the syndrome. These include antiserotonergic drugs, gastroprokinetic agents, branched-chain amino acids, eicosapentanoic acid, cannabinoids, melatonin, and thalidomide all of which act on the feeding-regulatory circuitry to increase appetite and inhibit tumor-derived catabolic factors to antagonize tissue wasting and/or host cytokine release. Because weight loss shortens the survival time of cancer patients and decreases performance status, effective therapy would extend patient survival and improve quality of life.

Aged↗
PubMed2000

Fishmeal supplementation to grazing dairy cows in early lactation.

Our objectives were to determine if grazing dairy cows would respond to fishmeal supplementation and to determine if responses could be explained by stimulation of adipose tissue lipolysis. Thirty-four multiparous Holstein cows (25+/-11 DIM) were supplemented with isonitrogenous concentrates containing either fishmeal or pelleted sunflower meal. On a dry matter (DM) basis, concentrates contained fishmeal (14.5%) or sunflower meal (24.2%), corn grain (55.6% and 50.6%), wheat bran (26.7% and 22%), a mineral-vitamin complex (2.9%) and a flavoring agent (0.3%). Concentrates were consumed at a rate of 5 kg/cow per day. Herbage allowance averaged 49.8+/-6.1 kg of DM/cow per d. Milk (26.8 vs. 25.2 kg/d), fat-corrected milk (23.9 vs. 22.2 kg/d) and milk protein yields (0.90 vs. 0.81 kg/d) were increased by fishmeal. Milk protein percentage was similar among treatments. Milk fat yield and milk and plasma urea nitrogen tended to be higher in cows fed fishmeal. Plasma glucose and nonesterified fatty acids concentrations and differences in concentrations between jugular and mammary veins were increased by fishmeal. The in vivo lipolytic response to a beta-adrenergic agent or the antilipolytic + hypoglycemic action of insulin were not affected. The higher milk production observed with fishmeal can be explained by the quantity and quality of the absorbed protein, higher glucose availability to the mammary gland, and increased lipid mobilization without change in responsiveness of the adipose tissue to lipolytic stimuli.

Adipose Tissue↗
PubMed2001

Undegradable protein supplementation to early-lactation dairy cows in grazing conditions.

To determine the production responses to rumen undegradable protein (RUP) feeding in grazing conditions, we fed 18 multiparous Holstein cows concentrates containing either soybean meal (SBM) or blood meal (BM) during the first 8 wk of lactation. One cow from the SBM treatment was removed because of mastitis. Six additional dairy cows in late lactation fitted with ruminal cannula were used to evaluate the rumen environment and the in situ crude protein (CP) degradability of concentrates. On a dry matter (DM) basis, concentrates contained SBM (33%) or BM (13%), corn grain (64 and 84% for SBM and BM, respectively) and a mineral-vitamin complex (3%). Concentrates were offered at a rate of 6.6 kg/d per cow and herbage allowance averaged 31 kg/d of DM per cow. The BM reduced ruminal ammonia-N levels and had no effect on ruminal pH and molar volatile fatty acid concentration. The degradable fraction (63.59 vs. 22.46%) and the rate of disappearance of the CP (9.68 vs. 1.69%/h) were greater for the SBM compared with the BM concentrate. Cows fed the BM concentrate produced more milk (29.3 vs. 24.9 kg/d) and more milk protein (0.85 vs. 0.74 kg/d) than did those fed the SBM concentrate. Milk fat yield and percentages of milk fat, lactose and protein were not affected. Forage DMI was increased by BM (17.19 vs. 13.17 kg/d per cow). The in vivo responsiveness to lipolytic stimuli were increased by BM but enhanced body weight loss or higher plasma nonesterified fatty acids concentration were not observed. Results indicated that a concentrate with a high RUP content increased milk and milk protein yields when spring pasture was the sole forage. The highest milk yield was more likely caused by increased DM than by enhanced body lipid mobilization.

Animal Feed↗
PubMed1991

Duodenal rapeseed oil infusion in early and midlactation cows. 4. In vivo and in vitro adipose tissue lipolytic responses.

In vitro glycerol and FFA releases from adipose tissue were studied in early (wk 3, trial 1) and midlactation (wk 19 to 26, trial 2) multiparous Holstein Friesian cows receiving a duodenal rapeseed oil infusion (1.0 to 1.1 kg/d). In trial 2, in vitro basal FFA release, basal FFA: glycerol ratio, and isoproterenol-stimulated FFA and glycerol releases were higher in perirenal adipose tissue from oil-infused cows. Plasma FFA concentration also was higher in oil-infused cows before and after intravenous isoproterenol injection. In trail 1, basal and stimulated glycerol and FFA releases from perirenal (but not subcutaneous) adipose tissue tended to be lower in oil-infused cows. This was probably linked to a lower milk production potential of oil-infused than of control cows which introduced a bias in energy balance. The basal FFA:glycerol ratio tended to be higher in oil-infused cows in both adipose tissues, suggesting a lower rate of reesterification inducted by oil, as was the case in trial 2. The alpha 2-agonist clonidine decreased perirenal adipose tissue glycerol release in cows and treatments in which the responses to 4 x 10(-7) M isoproterenol were higher. In vivo and in vitro lipolytic responses were lower in trial 2 than in trial 1, except the in vitro maximally stimulated lipolytic rate, which probably reflected a long lasting teleophoretic adaptation to ensure energy needs of lactation. This study indicated that oil infusion affected both beta- and alpha 2-adrenergic responses and that postpartum lipid mobilization did not seem to be reduced by the exogenous unsaturated fatty acid supply.

Adenosine Deaminase↗
PubMed1994

Effect of propylene glycol dosage during feed restriction on metabolites in blood of prepartum Holstein heifers.

Different doses of propylene glycol were compared for lowering plasma NEFA concentration during restricted feed intake. Eight Holstein heifers, averaging 90 d prior to calving at initiation of the trial, were in a 4 x 4 Latin square design with 12-d periods. Heifers consumed alfalfa silage on an ad libitum basis during d 1 to 7 of each period. During d 8 to 12, heifers were gradually restricted to 50% of ad libitum intake. Heifers received an oral drench of 0, 296, 592, or 887 ml of propylene glycol once daily at 6 h prior to feeding on d 8 to 12. Propylene glycol linearly increased glucose and insulin and decreased BHBA and NEFA in blood. Quadratic effects of propylene glycol on plasma glucose, BHBA, and NEFA also occurred; response per milliliter of propylene glycol was greatest at the lowest dose. The highest dose of propylene glycol returned blood glucose, insulin, and NEFA concentrations to those prior to feed restriction. Ruminal acetate to propionate ratio decreased as propylene glycol dose was increased, indicating ruminal conversion of propylene glycol to propionate. A dose of 296 ml of propylene glycol was almost as effective as a dose of 887 ml in reducing lipid mobilization during restricted feed intake.

3-Hydroxybutyric Acid↗
PubMedDate not supplied

Acute necrotizing encephalopathy: diffusion MR imaging and localized proton MR spectroscopic findings in two infants.

In this report, we describe the findings of diffusion MR imaging and proton MR spectroscopy in two infants with acute necrotizing encephalopathy in which there was characteristic symmetrical involvement of the thalami. Diffusion MR images of the lesions showed that the observed apparent diffusion coefficient (ADC) decrease was more prominent in the first patient, who had more severe brain damage and a poorer clinical outcome, than in the second. Proton MR spectroscopy detected an increase in the glutamate/glutamine complex and mobile lipids in the first case but only a small increase of lactate in the second. Diffusion MR imaging and proton MR spectroscopy may provide useful information not only for diagnosis but also for estimating the severity and clinical outcome of acute necrotizing encephalopathy.

Brain↗
PubMedDate not supplied

The effect of triiodothyronine (T3) on calorigenic and thermoregulatory responses to noradrenaline in the rabbit.

Calorigenic action of NA administered to conscious rabbits was potentiated by the prior injection of triiodothyronine (T3). The increased NA-induced heat production in these rabbits, accompanied by higher increases in body temperature in spite of improved heat elimination, can be at least partly attributed to more intensive lipid mobilization and utilization. A considerable hyperglycemic effect of NA was found both in the control-untreated and T3-treated rabbits.

Animals↗
PubMed1999

Is the somatopause an indication for growth hormone replacement?

In the normal population, a gradual and progressive fall in spontaneous growth hormone (GH) secretion occurs with increasing age and is reflected in a parallel fall in circulating insulin-like growth factor (IGF)-I, reduction in lean body mass, increase in body fat and rise in low-density lipoprotein (LDL) cholesterol. Aging is also associated with a progressive failure of body functions and particularly with an increasing lack of physical strength and mobility. Many problems of aging are attributable to the progressive loss of lean tissues and to catabolic events. This can be and often is associated with a progressive decline in independence and quality of life, leading eventually to a prolonged dependence on others, followed by a distressing process of death. By analogy with the fall in ovarian function that inevitably eventually occurs in women with increasing age, this fall in GH secretion has been termed the somatopause. In cross-sectional studies on elderly people, the amount of GH secreted spontaneously correlates well with "good risk factors" such as body composition, mobility, lipid profiles and blood pressure. The important question that these scientific facts raises is whether this fall in GH secretion with increasing years is an important physiological safety event of the normal aging process, or whether it marks the development of GH deficiency which would benefit from GH replacement. It is established that a number of the clinical features of the somatopause are shared with the syndrome of adult-onset GH deficiency and Rudman first proposed the importance of GH in maintaining health and vitality with increasing age many years ago. In 1989, GH replacement was shown to be beneficial in adults with GH deficiency, and in 1990 Rudman showed remarkably similar beneficial effects in a group of elderly men with low plasma IGF-I values, but no underlying pituitary pathology, who were administered GH. In these adults, low doses of GH increased lean body mass and bone mineral density, decreased body fat and lowered LDL cholesterol. Sleep and exercise are the two major stimuli for secretion of GH in normal people and there is evidence to indicate that the GH response to exercise is essential for developing and maintaining physical fitness. There is also some evidence to suggest that adults who continue to exercise with increasing age better maintain lean body mass and physiological GH secretion. So, is the somatopause due to lifestyle changes consequent upon indolence, too much TV and modern living? Is it better to chase our patients (and colleagues?) down to the gym three times a week or should we give them an injection of GH before they sit down with a can of lager to watch the World Cup? Should the fact that elite athletes in virtually all sports have decided from their own "clinical trials" that GH is a performance-enhancing drug, when combined with exercise, have any influence on our strategy? The long-term safety of GH replacement is clearly a matter for concern but we do now know that life without GH is poor both in quantity and quality. Is there a safe therapeutic window that allows GH replacement in the somatopause to add years to life, quality to these years, and maybe even improves the quality of death?

Adult↗
PubMed1976

Diurnal variation in the effect of melatonin on plasma and muscle free fatty acid levels in the pigeon.

Pigeons maintained on standard diet and held under 12 h daily photo-period in a controlled environmental room, were given intravenous injections of melatonin. A low dose (1.25 mg/kg body weight) of melatonin when given in the middle of the scotophase, produced a significant increase in plasma FFA when estimated at 20 min and 90 min post-injection, whereas no significant change was seen with injections given in the middle of the photophase. No significant change in muscle FFA level was obtained either during the photophase or the scotophase when estimated at 90 min postinjection. With a higher dose (5 mg/kg body weight) of melatonin given in the scotophase, on the other hand, a significant increase in both plasma as well as muscle FFA levels was obtained at 90 min post-injection but there was no effect on plasma FFA at 20 min or 90 min post-injection in the photophase and at 20 min in the scotophase. It is concluded that melatonin has a lipid mobilizing action in the pigeon when administered during the scotophase.

Animals↗