Insulin is a peptide hormone produced by beta cells in the pancreas. It regulates the metabolism of carbohydrates and fats by promoting the absorption of glucose from the blood to skeletal muscles and fat tissue and by causing fat to be stored rather than used for energy. Insulin also inhibits the production of glucose by the liver.
Contain or associate with multiple structural and signaling molecules including caveolin-1, Insulin Receptor (IR), IGF-1R, dynamin 2, actin filaments and eNOS. Early studies demonstrated that vascular Endothelial Cells (ECs) express IRs and that insulin TET is saturable and mediated by IRs. Subsequent in vivo studies also reported that at physiological insulin concentrations insulin TET into human skeletal muscle interstitium is saturable. However, several in vivo studies were unable to observe the saturation when supraphysiological insulin doses were applied during an insulin clamp. In 2006, we employed a different approach using confocal microscopy and serial muscle biopsies and found that intravenously infused Fluorescein Isothiocyanate (FITC)-labeled insulin rapidly localized within the vascular ECs of skeletal muscle but not in the intercellular clefts in vivo. Given that vascular ECs also possess IGF-1 receptors and IGF-1Rs are ~10x more abundant than IRs with a much lower affinity for insulins binding we found that both IGF-1 peptide and a neutralizing antibody against IGF-1R significantly inhibited insulin uptake and TET when a pharmacologic insulin concentration (50nM) was used. This has provided an alternative explanation for the seemingly conflicting data regarding the saturability of insulin transport into muscle, i.e. that at physiological insulin concentrations insulin TET is mediated predominantly by IRs but at supraphysiologic insulin concentrations both IR and IGF-1R (and IR/IGF-1R hybrid receptors) contribute to insulin TET. Caveolin-1, a 21-kDa integral membrane protein required for caveolae formation is required for receptor-mediated albumin uptake by vascular ECs.
Journal Article is sometimes called a Scientific Article, a Peer-Reviewed Article, or a Scholarly Research Article. Together, journal articles in a particular field are often referred to as The Literature.
Journal articles are most often Primary Research Articles. However, they can also be Review Articles. These types of articles have different aims and requirements. Sometimes, an article describes a new tool or method
Last date updated on July, 2014