The Effect of Insulin and Glucagon Before and After Meals
Insulin belongs to the group of peptide hormones. It takes part in the regulation of metabolism, transport of glucose, aminoacids, in protein biosynthesis (Sonksen P. and Sonksen J. 69). Insulin also influences replication and transcription processes, thus taking part in cell differentiation and proliferation (Saltiel A.R and Kahn R. 799) Insulin stimulates glucose utilization in cells via different ways.
Around 50 % glucose is used in glycolysis, up to 40 % is transformed into fats and 10 % is accumulated as glycogen. The final outcome of above mentioned processes is the decrease of the blood glucose concentration. In liver cells insulin induces glukokinase synthesis. As a result of the phosphorylation the free glucose concentration in cells is maintained on the low level thus facilitating glucose transport via concentration gradient.
Structure and function of glucagon
Glucagon is a peptide hormone produced by pancreas cells in response to the decrease of the glucose level in blood. Effect of the glucagon is opposite to that of the insulin. Major glucagon target cells are liver and fat tissue. In hepatocytes glucagon activates glycogen phosphorylase and lowers the activity of glycogen synthase (Jiang G. and Zhang B. E673). As a result the mobilization of glycogen is accelerated. Glucagon also stimulates gluconeogenesis by inducing synthesis of glucose-6-phosphatase, phosphoenolpyruvate carboxylase, fructose-1,6-biphosphatase (Van Schaftingen E. and Gerin I. 513).
Thus as opposed to insulin glucagon stimulates mobilization of major energy carriers: carbohydrates and fats.In relation to the insulin and glucagon interplay it is interesting to see how external supply of sugar containing food (postprandial state) and absence of such supply (fasting state) would affect blood glucose concentration.The following working hypothesis was formulated to be checked experimentally: glucose concentration in blood is affected by the nutritional status.
In the current laboratory experiment semi quantitative assay was used to demonstrate the change in blood glucose levels depending on nutritional status and type of blood vessels.Blood serum samples from mesenteric artery, hepatic vein and hepatic portal vein have been taken from fasting organism and after eating. Then samples were placed in test tubes, Benedict`s reagent was added and resulting solution was heated in the water bath. The change of color after 1 and 3 minutes was recorded for every experimental treatment.In the presence of alkali sugars in the blood serum react with copper containing Benedict`s reagent and reduce copper (II) to copper (I) which precipitates as red insoluble copper (I) oxide Cu
Effect of insulin and glucagon
Insulin and glucagon regulate metabolism of glucose in cells. They are two major peptide hormones that support homeostasis of glucose in the body. Working hypothesis: glucose concentration in blood is affected by the nutritional status.To verify this hypothesis blood serum glucose samples have been taken from human body before and after food intake. Samples were analyzed semi quantitatively for glucose content. Three types of blood vessels were examined: mesenteric artery (transports glucose from liver to intestines), hepatic portal vein (transports glucose from intestines to liver) and hepatic vein (transports glucose …
