New Findings r What is the central question of this study?The aim was to determine whether mitochondrial protein content of perilipin 3 (PLIN3) and perilipin 5 (PLIN5) is increased following endurance training and whether mitochondrial PLIN5 protein is increased to a greater extent in endurance-trained rats when compared with sedentary rats following acute contraction. r What is the main finding and its importance?Mitochondrial PLIN3 but not PLIN5 protein was increased in endurance-trained compared with sedentary rats, suggesting a mitochondrial role for PLIN3 due to chronic exercise. Contrary to our hypothesis, acute mitochondrial PLIN5 protein was similar in both sedentary and endurance-trained rats.Endurance training results in an increased association between skeletal muscle lipid droplets and mitochondria. This association is likely to be important for the expected increase in intramuscular fatty acid oxidation that occurs with endurance training. The perilipin family of lipid droplet proteins, PLIN(2-5), are thought to play a role in skeletal muscle lipolysis. Recently, results from our laboratory demonstrated that skeletal muscle mitochondria contain PLIN3 and PLIN5 protein. Furthermore, 30 min of stimulated contraction induces an increased mitochondrial PLIN5 content. To determine whether mitochondrial content of PLIN3 and PLIN5 is altered with endurance training, Sprague-Dawley rats were randomized into sedentary or endurance-trained groups for 8 weeks of treadmill running followed by an acute (30 min) sciatic nerve stimulation to induce lipolysis. Mitochondrial PLIN3 protein was ß1.5-fold higher in red gastrocnemius of endurance-trained rats compared with sedentary animals, with no change in mitochondrial PLIN5 protein. In addition, there was an increase in plantaris intramuscular lipid storage. Acute electrically stimulated contraction in red gastrocnemius from sedentary and endurance-trained rats resulted in a similar increase of mitochondrial PLIN5 between these two groups, with no net change in PLIN3 in either group. Plantaris intramuscular lipid content decreased to a similar extent in sedentary and endurance-trained rats. These results suggest that while total mitochondrial PLIN5 content is not altered by endurance training, PLIN5 does have an acute role in the mitochondrial fraction during muscle contraction. Conversely, mitochondrial PLIN3 does not change acutely with muscle contraction, but PLIN3 content IntroductionThe physiological adaptations to endurance training in skeletal muscle include, but are not limited to, increased oxidative capacity, intramuscular triglyceride storage and an increase in the proteins and enzymes involved in regulating oxidative phosphorylation (Davies et al. 1981;Hoppeler et al. 1985). These are important adaptations because they lead to an improvement in the ability of muscles to use stored triglycerides efficiently. An increased reliance on intramuscular triglycerides as a fuel source after endurance training has been demonstrated in both rodent (Molé et al. 19...
The doubly hydrogen-bonded dimer of pyrrolidinone (γ-lactam) is used as a benchmark for the effect of conjugation on the strength and extent of hydrogen-bonding of the compounds Oxindole and Isoxindole. The experimental portion of this project consists of collecting the FTIR spectrum of γ-lactam, Oxindole and Isoxindole in CCl4. The concentrations and temperatures were varied to determine the thermodynamic properties of ∆Hd, ∆Sd and Kd. In addition, the spectroscopic parameters of the difference of the monomer and dimer N-H stretching frequencies (∆ν) and the ratio of the molar extinction coefficients of the dimer and monomer (εd/εm) are experimentally determined. The values of ∆Hd, ∆Sd, ∆ν and εd/εm are computed using MP2 and B3LYP methods with 6-31G** and 6-31+G** basis sets. The experimental values are best described by B3LYP/6-31G**with the incorporation of the dielectric effect (PCM) of CCl4. The experimental and computational results support the results of increased or decreased hydrogen-bond strength due to conjugation effects on the polarization of the monomers in forming dimers.
High fat diets (HFD) can have adverse effects on skeletal muscle development. Skeletal muscle PLIN proteins (PLIN2, 3, & 5) are thought to play critical roles in lipid metabolism, however effects of HFD on PLINs as well as lipases (HSL, ATGL, CGI‐58) have yet to be investigated. The objective of this study was to determine whether HFD would influence skeletal muscle lipase and PLIN protein content in dams as well as offspring at weaning (19d) and young adulthood (3mo). Female rats (28d old, n=9/group) were fed control (CON, AIN93G, 7% soybean oil) or HFD (AIN93G, 20% lard) for 10wks prior to mating, throughout pregnancy and lactation. Offspring were weaned onto CON (n=18/group, one female & one male pup per litter was studied at 19d & 3mo of age). Because there was no effect of sex for outcomes measured, male and female data was combined. HFD resulted in increased lipid content in plantaris of dams and pups, both at weaning and at 3mo (p=0.07). HFD resulted in increased PLIN3 content in plantaris of dams (P=0.016) and increased PLIN5 content in pups at weaning and 3mo (p=0.05). PLIN2 and PLIN5 content increased at 3mo vs. weaning (P<0.001). Diet had no effect on ATGL, CGI‐58, or HSL content. The data suggest that exposure to a maternal HFD results in increased skeletal muscle lipid and PLIN5 content in offspring through to young adulthood. Funded by NSERC.
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