Cell-Cell Communication is a fundamental process that is essential for the regulation of metabolism in various organs. Through hormones of the endocrine system, signals are chemically transmitted through the bloostream between different organs. The outcome of a hormone binding its specific receptor in target tissues can produce profound effects on metabolism. Insulin and its effects on the liver, is used as an example of the outcome of communication between the pancreas and the liver.

This podcast covers the catabolism of alanine, glutamate and aspartate, including the roles of 3 important enzymes alanine transaminase (ALT), aspartate transaminase (AST) and glutamate dehydrogenage in this process. Input of nitrogen into the Urea cycle is provided directly or indirectly through the metabolism of the 3 discussed amino acids.

This podcast is an overview of the catabolism of amino acids including the initial phase of transferring amines through transaminases to an acceptor keto acid like Alpha-ketoglutarate to produce glutamate.

During fasting, fatty acids are mobilized from stored triacylglycerol in adipose tissue through the activation of Hormone-Sensitive Lipase by epinephrine which results in the release of 3 fatty acids to the bloodstream.

This podcast covers three misconceptions dietary fat and covers the crucial contributions of dietary fat to energy production/ storage, membrane synthesis, and inflammation. The key roles of cholesterol in cellular functions are also summarized.

This podcast covers some misconceptions about glucose and its perceived bad effects on health. Glucose is an essential energy source for many tissues that almost exclusively depend on it availability in the bloodstream. In fact, through coordinated release of hormones and their various tissue effects, glucose is maintained between 80-100 mg/ dl during fasting and sleep with the purpose of supplying glucose to tissues that depend on it. Restoring blood glucose under fasting conditions is primarily accomplished by the liver. Although elevated plasma glucose can cause some health risks, the tissue requirement for glucose as an energy source can not be overlooked.

This podcast the dependence of the brain on glucose as an energy source. Although the brain can use ketone bodies, it only does that in prolonged fasts. Instead the brain can instruct other organs to release hormones that will restore blood glucose.

This pocast covers the endocrine pancreas and the role of the beta cells in secretion of insulin. The rise in bloodstream glucose triggers the increase of glucose uptake by the pancreas by glut-2 transporter, followed by an increase in glycolysiss and a rise in ATP in the cytoplasm. This rise triggers a cascade of events inside the beta cells leading to insulin release.

This podcast covers the major glucose transporters, their tissue distribution, and regulation by hormones. The key role of these transporters is to pick up glucose from the bloodstream so it can be further metabolized by the cell.

This podcast covers 4 distinct classes of receptors and their respective hormones, including the mechanism of transducing their intracellular signals. The receptors covered in detail are the steroid receptor, the insulin receptor, and 3 distinct G-protein coupled receptors, including the second messengers they produce.