Project description:Seventeen northern elephant seal pups constituting four different cohorts at Año Nuevo State Reserve were studied at two post-weaning periods: early (1-2 wk post weaning; n=5) and late (6-7 weeks post weaning; n=12). Study #1: Prior to each infusion protocol, plasma U/kg). Following the infusion, blood samples were collected at 10,To determine the effects of prolonged fasting on peripheral insulin activity and function, samples were collected. Ten fasting seal pups (n=5 early, n=5 late) were infused (i.v.) with a mass-specific dose of insulin (0.065 U/kg). Following the infusion, blood samples were collected at 10, 30, 60, 90, and 120 minutes. Study #2: Seven, late-fasted seal pups were administered either a low (LDG; 10 pmol/kg; n=3) or high (HDG; 100 pmol/kg; n=4) dose of GLP-1 immediately following a glucose bolus (0.5 g/kg) (i.v.) infused within 2 mins. the infusions, blood samples were collected at 10, 30, 60, 90, 120, and 150 minutes.
Project description:The aim was to study the effects of Nur77 on the white adipose tissue transcriptome after fasting. For this purpose we performed gene expression profiling of white adipose tissue from Nur77-/- mice and wildtype (Nur77+/+) littermates submitted to prolonged fasting using microarray analysis on >27k elements cDNA microarrays.
Project description:Prolonged fasting-induced changes in rat white adipose tissue (epidydimal) transcriptome White adipose tissue is a central place to energy storage and a major endocrine organ. However, adipose molecular mechanisms have been poorly studied during prolonged fasting. To fill this gap, the aim of this study was to decipher transcriptomic regulations in rat adipose tissue during phase 2 (lipid mobilization) and phase 3 (protein catabolism) of prolonged fasting compared to the fed state. We describe a regulatory transcriptional program in epididymal adipose tissue in line with lipogenesis repression during both phases, and that would favor lipolysis during phase 2 and repress it during phase 3. Such regulations notably involve selective (i.e. phase-dependent) changes in gene expression levels of lipases, lipid droplet-associated factors, and the proteins involved in cAMP-dependent and cAMP-independent regulation of lipolysis. The mRNA levels of adipose-secreted factors were globally consistent with the repression of insulin signalling during prolonged fasting. Regulations of leptin and adiponectin levels could be related to their respective role in triggering refeeding during late fasting and controlling lipid metabolism. Specific responses reflecting adipose tissue inflammation, increased fibrinolysis and a possible protein catabolism-related energy saving mechanism were also recorded during phase 3. These data thus provide a comprehensive molecular basis of adipose tissue responses according to the fasting stage.
Project description:White adipose tissue is a central place to energy storage and a major endocrine organ. However, adipose molecular mechanisms have been poorly studied during prolonged fasting. To fill this gap, the aim of this study was to decipher proteomic regulations in rat adipose tissue during phase 2 (lipid mobilization) and phase 3 (protein catabolism) of prolonged fasting compared to the fed state. Specific responses reflecting adipose tissue inflammation, increased fibrinolysis and a possible protein catabolism-related energy saving mechanism were recorded during phase 3. Differences between internal and subcutaneous adipose tissues were essentially related to lipid metabolism, the response to oxidative stress and energy production. These data thus provide a molecular basis of adipose tissue responses according to the fasting stage.
