135. FATTY ACID OXIDATION IS ESSENTIAL FOR OOCYTE DEVELOPMENTAL COMPETENCE

2009 ◽  
Vol 21 (9) ◽  
pp. 54
Author(s):  
K. R. Dunning ◽  
K. Cashman ◽  
R. J. Norman ◽  
R. L. Robker
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Oocyte Maturation ◽  
Dietary Fat ◽  
Fold Increase ◽  
Developmental Competence ◽  
Acid Oxidation ◽  
Oocyte Developmental Competence ◽  
Carnitine Palmitoyltransferase 1

Oocyte lipid composition and developmental competence are influenced by dietary fat yet whether lipids are metabolised by the oocyte or essential for subsequent embryo development is largely unexplored. Fatty acid oxidation (FAO) is largely overlooked as an energy source for the oocyte, despite generating several-fold more energy than glucose oxidation. FAO requires the rate-limiting enzyme carnitine palmitoyltransferase-1 (Cpt1) and the metabolite Carnitine to shuttle fatty acids into mitochondria for energy production. Analysis of Cpt1 mRNA during oocyte maturation showed that Cpt1 expression was hormonally induced (p<0.05) in the cumulus oocyte complex (COC), peaking at 10h following ovulatory hCG treatment. In contrast, Cpt1 was not hormonally regulated in granulosa cells (p>0.05). To investigate the role of Cpt1-mediated FAO during oocyte maturation we measured FAO in oocytes in the presence and absence of Carnitine and inhibited FAO to determine its importance for oocyte developmental competence. Levels of FAO in COCs were assessed as metabolism of the fatty acid 3H-palmitate. During oocyte maturation there was a 2.1-fold increase (p<0.0001) in FAO compared to immature COCs. Carnitine supplementation led to a further 3.7-fold increase (p<0.001), while inhibition of Cpt1 with Etomoxir resulted in a 6.5-fold decrease (p<0.0002) in FAO during oocyte maturation. FAO inhibition had no effect on cumulus expansion. However inhibition of FAO during oocyte maturation followed by IVF and embryo culture in the absence of inhibitor, resulted in significantly decreased numbers of embryos developing ‘on time' (p<0.002). This is the first identification of hormonal induction of Cpt1 and Cpt1 mediated FAO in the COC during oocyte maturation. Further, the results demonstrate that oxidation of fatty acids by the oocyte is essential for oocyte developmental competence and can be modulated by Carnitine. These findings provide a potential mechanism by which dietary fat, obesity or metabolic disorders including CPT deficiency lead to infertility.

scholarly journals Adenovirus-mediated overexpression of liver carnitine palmitoyltransferase I in INS1E cells: effects on cell metabolism and insulin secretion

2002 ◽  
Vol 364 (1) ◽  
pp. 219-226 ◽  
Author(s):  
Blanca RUBÍ ◽  
Peter A. ANTINOZZI ◽  
Laura HERRERO ◽  
Hisamitsu ISHIHARA ◽  
Guillermina ASINS ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Insulin Secretion ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Fold Increase ◽  
Acid Oxidation ◽  
Β Cells ◽  
Β Cell ◽  
Carnitine Palmitoyltransferase I ◽  
Cpt I

Lipid metabolism in the β-cell is critical for the regulation of insulin secretion. Pancreatic β-cells chronically exposed to fatty acids show higher carnitine palmitoyltransferase I (CPT I) protein levels, higher palmitate oxidation rates and an altered insulin response to glucose. We examined the effect of increasing CPT I levels on insulin secretion in cultured β-cells. We prepared a recombinant adenovirus containing the cDNA for the rat liver isoform of CPT I. The overexpression of CPT I in INS1E cells caused a more than a 5-fold increase in the levels of CPT I protein (detected by Western blotting), a 6-fold increase in the CPT activity, and an increase in fatty acid oxidation at 2.5mM glucose (1.7-fold) and 15mM glucose (3.1-fold). Insulin secretion was stimulated in control cells by 15mM glucose or 30mM KCl. INS1E cells overexpressing CPT I showed lower insulin secretion on stimulation with 15mM glucose (−40%; P<0.05). This decrease depended on CPT I activity, since the presence of etomoxir, a specific inhibitor of CPT I, in the preincubation medium normalized the CPT I activity, the fatty-acid oxidation rate and the insulin secretion in response to glucose. Exogenous palmitate (0.25mM) rescued glucose-stimulated insulin secretion (GSIS) in CPT I-overexpressing cells, indicating that the mechanism of impaired GSIS was through the depletion of a critical lipid. Depolarizing the cells with KCl or intermediary glucose concentrations (7.5mM) elicited similar insulin secretion in control cells and cells overexpressing CPT I. Glucose-induced ATP increase, glucose metabolism and the triacylglycerol content remained unchanged. These results provide further evidence that CPT I activity regulates insulin secretion in the β-cell. They also indicate that up-regulation of CPT I contributes to the loss of response to high glucose in β-cells exposed to fatty acids.

scholarly journals Lipids and oocyte developmental competence: the role of fatty acids and β-oxidation

Reproduction ◽  
2014 ◽  
Vol 148 (1) ◽  
pp. R15-R27 ◽  
Author(s):  
Kylie R Dunning ◽  
Darryl L Russell ◽  
Rebecca L Robker
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Embryo Development ◽  
Oocyte Maturation ◽  
Unsaturated Fatty Acids ◽  
Cumulus Cells ◽  
Developmental Competence ◽  
Oocyte Developmental Competence

Metabolism and ATP levels within the oocyte and adjacent cumulus cells are associated with quality of oocyte and optimal development of a healthy embryo. Lipid metabolism provides a potent source of energy and its importance during oocyte maturation is being increasingly recognised. The triglyceride and fatty acid composition of ovarian follicular fluid has been characterised for many species and is influenced by nutritional status (i.e. dietary fat, fasting, obesity and season) as well as lactation in cows. Lipid in oocytes is a primarily triglyceride of specific fatty acids which differ by species, stored in distinct droplet organelles that re-localise during oocyte maturation. The presence of lipids, particularly saturated vs unsaturated fatty acids, in in vitro maturation systems affects oocyte lipid content as well as developmental competence. Triglycerides are metabolised by lipases that have been localised to cumulus cells as well as oocytes. Fatty acids generated by lipolysis are further metabolised by β-oxidation in mitochondria for the production of ATP. β-oxidation is induced in cumulus–oocyte complexes (COCs) by the LH surge, and pharmacological inhibition of β-oxidation impairs oocyte maturation and embryo development. Promoting β-oxidation with l-carnitine improves embryo development in many species. Thus, fatty acid metabolism in the mammalian COC is regulated by maternal physiological and in vitro environmental conditions; and is important for oocyte developmental competence.

The 1993 Merck Frosst Award. Acetyl-CoA carboxylase: an important regulator of fatty acid oxidation in the heart

1994 ◽  
Vol 72 (10) ◽  
pp. 1101-1109 ◽  
Author(s):  
Gary D. Lopaschuk ◽  
Jim Gamble
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Carbohydrate Oxidation ◽  
Acid Oxidation ◽  
Acetyl Coa ◽  
Atp Production ◽  
Malonyl Coa ◽  
Important Regulator ◽  
Carnitine Palmitoyltransferase 1

It has long been known that most of the energy production in the heart is derived from the oxidation of fatty acids. The other important sources of energy are the oxidation of carbohydrates and, to a lesser extent, ATP production from glycolysis. The contribution of these pathways to overall ATP production can vary dramatically, depending to a large extent on the carbon substrate profile delivered to the heart, as well as the presence or absence of underlying pathology within the myocardium. Despite extensive research devoted to the study of the individual pathways of energy substrate metabolism, relatively few studies have examined the integrated regulation between carbohydrate and fatty acid oxidation in the heart. While the mechanisms by which fatty acids inhibit carbohydrate oxidation (i.e., the Randle cycle) have been characterized, much less is known about how carbohydrates regulate fatty acid oxidation in the heart. It is clear that an increase in intramitochondrial acetyl-CoA derived from carbohydrate oxidation (via the pyruvate dehydrogenase complex) can downregulate β-oxidation of fatty acids, but it is not clear how fatty acid acyl group entry into the mitochondria is downregulated when carbohydrate oxidation increases. Recent interest in our laboratory has focused on the involvement of acetyl-CoA carboxylase (ACC) in this process. While it has been known for some time that malonyl-CoA does exist in heart tissue, and that it is a potent inhibitor of carnitine palmitoyltransferase 1 (CPT 1), it has only recently been demonstrated that an isoenzyme of ACC exists in the heart that is a potential source of malonyl-CoA. These findings led to the hypothesis that ACC may be an important regulator of myocardial fatty acid oxidation. We have recently provided evidence that heart ACC, via the production of malonyl-CoA, can regulate fatty acid oxidation. We believe that ACC represents a key enzyme in a feedback loop that decreases acyl-CoA transport into the mitochondria when carbohydrate oxidation rates are increased. It is possible that ACC may represent a novel and potentially important site for pharmacological intervention in pathological situations characterized by abnormal fatty acid metabolism. This review provides a brief overview of the regulation of myocardial metabolism followed by our recent studies that support the hypothesis that ACC has an important role in regulating the balance between carbohydrate and lipid metabolism in the heart.Key words: fatty acids, glucose, malonyl-CoA, carnitine palmitoyltransferase 1, myocardial ischemia.

scholarly journals Mitochondrial Fission Governed by Drp1 Regulates Exogenous Fatty Acid Usage and Storage in Hela Cells

Metabolites ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 322
Author(s):  
Jae-Eun Song ◽  
Tiago C. Alves ◽  
Bernardo Stutz ◽  
Matija Šestan-Peša ◽  
Nicole Kilian ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Lipid Droplets ◽  
Mitochondrial Fission ◽  
Acid Oxidation ◽  
Mitochondrial Morphology ◽  
Mitochondrial Fatty Acid Oxidation ◽  
Mitochondrial Fatty Acid ◽  
And Storage

In the presence of high abundance of exogenous fatty acids, cells either store fatty acids in lipid droplets or oxidize them in mitochondria. In this study, we aimed to explore a novel and direct role of mitochondrial fission in lipid homeostasis in HeLa cells. We observed the association between mitochondrial morphology and lipid droplet accumulation in response to high exogenous fatty acids. We inhibited mitochondrial fission by silencing dynamin-related protein 1(DRP1) and observed the shift in fatty acid storage-usage balance. Inhibition of mitochondrial fission resulted in an increase in fatty acid content of lipid droplets and a decrease in mitochondrial fatty acid oxidation. Next, we overexpressed carnitine palmitoyltransferase-1 (CPT1), a key mitochondrial protein in fatty acid oxidation, to further examine the relationship between mitochondrial fatty acid usage and mitochondrial morphology. Mitochondrial fission plays a role in distributing exogenous fatty acids. CPT1A controlled the respiratory rate of mitochondrial fatty acid oxidation but did not cause a shift in the distribution of fatty acids between mitochondria and lipid droplets. Our data reveals a novel function for mitochondrial fission in balancing exogenous fatty acids between usage and storage, assigning a role for mitochondrial dynamics in control of intracellular fuel utilization and partitioning.

Isotope tracer measures of meal fatty acid metabolism: reproducibility and effects of the menstrual cycle

2005 ◽  
Vol 288 (3) ◽  
pp. E547-E555 ◽  
Author(s):  
Ana Paola Uranga ◽  
James Levine ◽  
Michael Jensen
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Menstrual Cycle ◽  
Dietary Fat ◽  
Fatty Acid Uptake ◽  
Upper Body ◽  
Acid Oxidation ◽  
Acid Uptake ◽  
Lower Body

Oxidation and adipose tissue uptake of dietary fat can be measured by adding fatty acid tracers to meals. These studies were conducted to measure between-study variability of these types of experiments and assess whether dietary fatty acids are handled differently in the follicular vs. luteal phase of the menstrual cycle. Healthy normal-weight men ( n = 12) and women ( n = 12) participated in these studies, which were block randomized to control for study order, isotope ([3H]triolein vs. [14C]triolein), and menstrual cycle. Energy expenditure (indirect calorimetry), meal fatty acid oxidation, and meal fatty acid uptake into upper body and lower body subcutaneous fat (biopsies) 24 h after the experimental meal were measured. A greater portion of meal fatty acids was stored in upper body subcutaneous adipose tissue (24 ± 2 vs. 16 ± 2%, P < 0.005) and lower body fat (12 ± 1 vs. 7 ± 1%, P < 0.005) in women than in men. Meal fatty acid oxidation (3H2O generation) was greater in men than in women (52 ± 3 vs. 45 ± 2%, P = 0.04). Leg adipose tissue uptake of meal fatty acids was 15 ± 2% in the follicular phase of the menstrual cycle and 10 ± 1% in the luteal phase ( P = NS). Variance in meal fatty acid uptake was somewhat ( P = NS) greater in women than in men, although menstrual cycle factors did not contribute significantly. We conclude that leg uptake of dietary fat is slightly more variable in women than in men, but that there are no major effects of menstrual cycle on meal fatty acid disposal.

Meal composition affects postprandial fatty acid oxidation

1993 ◽  
Vol 264 (6) ◽  
pp. R1065-R1070 ◽  
Author(s):  
D. M. Surina ◽  
W. Langhans ◽  
R. Pauli ◽  
C. Wenk
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Nutrient Utilization ◽  
Whole Body ◽  
Acid Oxidation ◽  
Plasma Ffa ◽  
Hepatic Fatty Acid Oxidation ◽  
Beta Hydroxybutyrate ◽  
Chain Fatty Acids

The influence of macronutrient content of a meal on postprandial fatty acid oxidation was investigated in 13 Caucasian males after consumption of a high-fat (HF) breakfast (33% carbohydrate, 52% fat, 15% protein) and after an equicaloric high-carbohydrate (HC) breakfast (78% carbohydrate, 6% fat, 15% protein). The HF breakfast contained short- and medium-chain fatty acids, as well as long-chain fatty acids. Respiratory quotient (RQ) and plasma beta-hydroxybutyrate (BHB) were measured during the 3 h after the meal as indicators of whole body substrate oxidation and hepatic fatty acid oxidation, respectively. Plasma levels of free fatty acids (FFA), triglycerides, glucose, insulin, and lactate were also determined because of their relationship to nutrient utilization. RQ was significantly lower and plasma BHB was higher after the HF breakfast than after the HC breakfast, implying that more fat is burned in general and specifically in the liver after an HF meal. As expected, plasma FFA and triglycerides were higher after the HF meal, and insulin and lactate were higher after the HC meal. In sum, oxidation of ingested fat occurred in response to a single HF meal.

Effect of Age and Dietary Fat Level on Fatty Acid Oxidation in the Neonatal Pig

1978 ◽  
Vol 108 (10) ◽  
pp. 1621-1634 ◽  
Author(s):  
Ronald G. Wolfe ◽  
Charles V. Maxwell ◽  
Eldon C. Nelson
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Dietary Fat ◽  
Acid Oxidation ◽  
Fat Level ◽  
Neonatal Pig ◽  
Effect Of Age

Impact of 1 wk of diabetes on the regulation of myocardial carbohydrate and fatty acid oxidation

1999 ◽  
Vol 277 (2) ◽  
pp. E342-E351 ◽  
Author(s):  
John C. Chatham ◽  
Zhi-Ping Gao ◽  
John R. Forder
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Fold Increase ◽  
Diabetic Rats ◽  
Diabetic Group ◽  
Acid Oxidation ◽  
Oxidation Rates ◽  
Tissue Extracts ◽  
Isotopomer Analysis ◽  
C Nmr

The aim of this study was to investigate the effect of increasing exogenous palmitate concentration on carbohydrate and palmitate oxidation in hearts from control and 1-wk diabetic rats. Hearts were perfused with glucose, [3-13C]lactate, and [U-13C]palmitate. Substrate oxidation rates were determined by combining13C-NMR glutamate isotopomer analysis of tissue extracts with measurements of oxygen consumption. Carbohydrate oxidation was markedly depressed after diabetes in the presence of low (0.1 mM) but not high (1.0 mM) palmitate concentration. Increasing exogenous palmitate concentration 10-fold resulted in a 7-fold increase in the contribution of palmitate to energy production in controls but only a 30% increase in the diabetic group. Consequently, at 0.1 mM palmitate, the rate of fatty acid oxidation was higher in the diabetic group than in controls; however, at 1.0 mM fatty acid oxidation, it was significantly depressed. Therefore, after 1 wk of diabetes, the major differences in carbohydrate and fatty acid metabolism occur primarily at low rather than high exogenous palmitate concentration.

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