GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Intramuscular triglyceride synthesis: importance in muscle lipid partitioning in humans
    American Physiological Society ; 2018
    In:  American Journal of Physiology-Endocrinology and Metabolism Vol. 314, No. 2 ( 2018-02-01), p. E152-E164
    Details
    In: American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 314, No. 2 ( 2018-02-01), p. E152-E164
    Abstract: Intramuscular triglyceride (IMTG) concentration is elevated in insulin-resistant individuals and was once thought to promote insulin resistance. However, endurance-trained athletes have equivalent concentration of IMTG compared with individuals with type 2 diabetes, and have very low risk of diabetes, termed the “athlete’s paradox.” We now know that IMTG synthesis is positively related to insulin sensitivity, but the exact mechanisms for this are unclear. To understand the relationship between IMTG synthesis and insulin sensitivity, we measured IMTG synthesis in obese control subjects, endurance-trained athletes, and individuals with type 2 diabetes during rest, exercise, and recovery. IMTG synthesis rates were positively related to insulin sensitivity, cytosolic accumulation of DAG, and decreased accumulation of C18:0 ceramide and glucosylceramide. Greater rates of IMTG synthesis in athletes were not explained by alterations in FFA concentration, DGAT1 mRNA expression, or protein content. IMTG synthesis during exercise in Ob and T2D indicate utilization as a fuel despite unchanged content, whereas IMTG concentration decreased during exercise in athletes. mRNA expression for genes involved in lipid desaturation and IMTG synthesis were increased after exercise and recovery. Further, in a subset of individuals, exercise decreased cytosolic and membrane di-saturated DAG content, which may help explain insulin sensitization after acute exercise. These data suggest IMTG synthesis rates may influence insulin sensitivity by altering intracellular lipid localization, and decreasing specific ceramide species that promote insulin resistance.
    Type of Medium: Online Resource
    ISSN: 0193-1849 , 1522-1555
    URL: Article
    DOI: 10.1152/ajpendo.00142.2017
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2018
    detail.hit.zdb_id: 1477331-4
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Skeletal muscle phosphatidylcholine and phosphatidylethanolamine are related to insulin sensitivity and respond to acute exercise in humans
    American Physiological Society ; 2016
    In:  Journal of Applied Physiology Vol. 120, No. 11 ( 2016-06-01), p. 1355-1363
    Details
    In: Journal of Applied Physiology, American Physiological Society, Vol. 120, No. 11 ( 2016-06-01), p. 1355-1363
    Abstract: Several recent reports indicate that the balance of skeletal muscle phosphatidylcholine (PC) and phosphatidylethanolamine (PE) is a key determinant of muscle contractile function and metabolism. The purpose of this study was to determine relationships between skeletal muscle PC, PE and insulin sensitivity, and whether PC and PE are dynamically regulated in response to acute exercise in humans. Insulin sensitivity was measured via intravenous glucose tolerance in sedentary obese adults (OB; n = 14), individuals with type 2 diabetes (T2D; n = 15), and endurance-trained athletes (ATH; n = 15). Vastus lateralis muscle biopsies were obtained at rest, immediately after 90 min of cycle ergometry at 50% maximal oxygen consumption (V̇o 2 max ), and 2-h postexercise (recovery). Skeletal muscle PC and PE were measured via infusion-based mass spectrometry/mass spectrometry analysis. ATH had greater levels of muscle PC and PE compared with OB and T2D ( P 〈 0.05), with total PC and PE positively relating to insulin sensitivity (both P 〈 0.05). Skeletal muscle PC:PE ratio was elevated in T2D compared with OB and ATH ( P 〈 0.05), tended to be elevated in OB vs. ATH ( P = 0.07), and was inversely related to insulin sensitivity among the entire cohort ( r = −0.43, P = 0.01). Muscle PC and PE were altered by exercise, particularly after 2 h of recovery, in a highly group-specific manner. However, muscle PC:PE ratio remained unchanged in all groups. In summary, total muscle PC and PE are positively related to insulin sensitivity while PC:PE ratio is inversely related to insulin sensitivity in humans. A single session of exercise significantly alters skeletal muscle PC and PE levels, but not PC:PE ratio.
    Type of Medium: Online Resource
    ISSN: 8750-7587 , 1522-1601
    URL: Article
    DOI: 10.1152/japplphysiol.00664.2015
    RVK:
    WA 15000
    RVK:
    XA 52094
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2016
    detail.hit.zdb_id: 1404365-8
    SSG: 12
    SSG: 31
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Serum sphingolipids: relationships to insulin sensitivity and changes with exercise in humans
    American Physiological Society ; 2015
    In:  American Journal of Physiology-Endocrinology and Metabolism Vol. 309, No. 4 ( 2015-08-15), p. E398-E408
    Details
    In: American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 309, No. 4 ( 2015-08-15), p. E398-E408
    Abstract: Ceramides and sphingolipids are a family of lipid molecules that circulate in serum and accumulate in skeletal muscle, promoting insulin resistance. Plasma ceramide and dihydroceramide are related to insulin resistance, yet less is known regarding other ceramide and sphingolipid species. Despite its association with insulin sensitivity, chronic endurance exercise training does not change plasma ceramide and sphingolipid content, with little known regarding a single bout of exercise. We measured basal relationships and the effect of acute exercise (1.5 h at 50% V̇o 2 max ) and recovery on serum ceramide and sphingolipid content in sedentary obese individuals, endurance-trained athletes, and individuals with type 2 diabetes (T2D). Basal serum C18:0, C20:0, and C24:1 ceramide and C18:0 and total dihydroceramide were significantly higher in T2D and, along with C16:0 ceramide and C18:0 sphingomyelin, correlated positively with insulin resistance. Acute exercise significantly increased serum ceramide, glucosylceramide, and GM3 gangliosides, which largely decreased to basal values in recovery. Sphingosine 1-phosphate and sphingomyelin did not change during exercise but decreased below basal values in recovery. Serum C16:0 and C18:0 ceramide and C18:0 sphingomyelin, but not the total concentrations of either of them, were positively correlated with markers of muscle NF-κB activation, suggesting that specific species activate intracellular inflammation. Interestingly, a subset of sphingomyelin species, notably C14:0, C22:3, and C24:4 species, was positively associated with insulin secretion and glucose tolerance. Together, these data show that unique ceramide and sphingolipid species associate with either protective or deleterious features for diabetes and could provide novel therapeutic targets for the future.
    Type of Medium: Online Resource
    ISSN: 0193-1849 , 1522-1555
    URL: Article
    DOI: 10.1152/ajpendo.00134.2015
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2015
    detail.hit.zdb_id: 1477331-4
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Intermuscular adipose tissue directly modulates skeletal muscle insulin sensitivity in humans
    American Physiological Society ; 2019
    In:  American Journal of Physiology-Endocrinology and Metabolism Vol. 316, No. 5 ( 2019-05-01), p. E866-E879
    Details
    In: American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 316, No. 5 ( 2019-05-01), p. E866-E879
    Abstract: Intermuscular adipose tissue (IMAT) is negatively related to insulin sensitivity, but a causal role of IMAT in the development of insulin resistance is unknown. IMAT was sampled in humans to test for the ability to induce insulin resistance in vitro and characterize gene expression to uncover how IMAT may promote skeletal muscle insulin resistance. Human primary muscle cells were incubated with conditioned media from IMAT, visceral (VAT), or subcutaneous adipose tissue (SAT) to evaluate changes in insulin sensitivity. RNAseq analysis was performed on IMAT with gene expression compared with skeletal muscle and SAT, and relationships to insulin sensitivity were determined in men and women spanning a wide range of insulin sensitivity measured by hyperinsulinemic-euglycemic clamp. Conditioned media from IMAT and VAT decreased insulin sensitivity similarly compared with SAT. Multidimensional scaling analysis revealed distinct gene expression patterns in IMAT compared with SAT and muscle. Pathway analysis revealed that IMAT expression of genes in insulin signaling, oxidative phosphorylation, and peroxisomal metabolism related positively to donor insulin sensitivity, whereas expression of macrophage markers, inflammatory cytokines, and secreted extracellular matrix proteins were negatively related to insulin sensitivity. Perilipin 5 gene expression suggested greater IMAT lipolysis in insulin-resistant individuals. Combined, these data show that factors secreted from IMAT modulate muscle insulin sensitivity, possibly via secretion of inflammatory cytokines and extracellular matrix proteins, and by increasing local FFA concentration in humans. These data suggest IMAT may be an important regulator of skeletal muscle insulin sensitivity and could be a novel therapeutic target for skeletal muscle insulin resistance.
    Type of Medium: Online Resource
    ISSN: 0193-1849 , 1522-1555
    URL: Article
    DOI: 10.1152/ajpendo.00243.2018
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2019
    detail.hit.zdb_id: 1477331-4
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...