The Effect of Insulin and Glucagon Before and after Meals

Introduction

 Insulin and Glucagon hormones play a critical role in regulating the amount of blood glucose. In most tissues, blood glucose levels are normally expected to rise after a meal. Insulin regulates the amount of glucose after a meal by initiating several signaling pathways. The first pathway involves the consumption of more glucose by the cells. The second pathway involves the activation of the glycolytic pathway and the last one involves the conversion of excess sugar into fats (Röder, Wu, Liu, & Han, 2016). On the other hand, Glucagon hormone is released when the blood sugar levels fall. Glucagon initiates the Gluconeogenesis pathway which is considered as reverse glycolysis and the breakdown of reserve sugar in form of glycogen to glucose (Godoy-Matos, 2014). The action of one hormone inhibits the action of the other.

 Blood glucose is transported through a number of vessels. It is common for blood glucose levels to vary across different blood vessels based on the role of the vessel. Nonetheless, the action of the Insulin and Glucagon hormones, ensures that the homeostatic role of blood glucose is maintained at all times. Slight deviations in the regulation of blood glucose levels by the two hormones could easily predispose an individual to various disease conditions (Fu, Gilbert, & Liu, 2013). Thus, blood samples taken from healthy individuals at any given times are expected to have some little variation.  Three vessels that transport blood glucose include the mesenteric arteries, hepatic vein and the hepatic portal vein. Mesenteric arteries normally take blood from the aorta and redistribute the blood primarily to the gastrointestinal parts. Hepatic vein carries deoxygenated blood from within then liver and takes the blood towards the inferior vena cava while the hepatic portal vein carries the blood from the gastrointestinal parts of the body and other parts including the gall bladder and pancreas to the liver. An experiment was carried out with the aim of examining the relative concentration of glucose across the mesenteric arteries, hepatic portal
vein, and hepatic vein before and after the meal.

Objective

 To determine the relative concentration of glucose across the mesenteric arteries, hepatic portal vein, and hepatic vein before and after the meal.

Hypothesis

  Null hypothesis.  The relative concentration of glucose across the mesenteric arteries, hepatic portal vein, and hepatic vein is the same before and after the meal.

 Alternate Hypothesis. The relative concentration of glucose across the mesenteric arteries, hepatic portal vein, and hepatic vein is not the same before and after the meal.

Materials and Methods

  The materials used in the above experiment included a metric ruler, 6 test tubes,  test tube rack, marking pen, test tube holder, beaker, Benedict’s reagent, and hot plate. Fasting serum samples were collected from the mesenteric arteries, hepatic portal vein, and hepatic vein while postprandial samples (after eating) were collected from the mesenteric arteries, hepatic portal vein, and hepatic vein.

The test was not quantitative in nature and was thus used to compare the relative quantities of glucose in serum samples by observing how quickly the reaction occurred and degree of change in color. Serum samples were placed in tubes and were heated by Benedict’s solution. A water bath was then prepared. At the same time a metric ruler was used to mark off 6 tubes at 1 cm and 2 cm from the bottom to indicate the volume of serum and reagent which was to be used in the experiment. All the tubes were marked according to the blood vessels they came from and from the appropriate samples before and after eating. All the tubes were filled to its required levels before and after eating. Each tube was labelled accordingly with the serum on the first mark. Benedict reagent was then added to the second mark. The three postprandial samples were then simultaneously heat in a water bath and the time taken for the color changes were recorded after 3 minutes. The three fasting samples were also placed under the same experimental conditions. Benedict reagent changes from blue (negative) to yellow, orange then to red as glucose were noted as glucose levels increased in the samples. The Benedicts reagent used was then disposed in the appropriate waste jar after all experimental procedures were carried out.

Results

 The samples from the mesenteric arteries, hepatic portal vein, and hepatic vein all provided different colors before and after meals.  The images for the color changes for the various samples are indicated in the figure 1.1 below

Figure 1. 1 Blood Glucose levels for the three blood vessels after the application of the Benedicts test.

A description of the various colors obtained after the experiments and for the different hormones insulin and Glucagon is provided Table 1.1 and Table 1.2 respectively.

Table 1. 1 Postprandial data for Insulin hormone

Table 1. 2 Fasting data for Glucagon hormone

Discussion

  The null hypothesis indicates that the relative concentration of glucose across the mesenteric arteries, hepatic portal vein, and hepatic vein is the same before and after the meal is supported by the above results. In the above experimental set up, the final color changes of the various sugar types remained the same before and after meals. The red color which signifies high amount of glucose in the hepatic portal vein is an indicator that the vessel carries blood  rich in glucose from the gastrointestinal parts probably after food consumption and maintains the same activity throughout its course. The above results also serve to indicate that insulin and glucagon hormone regulate blood sugar levels across the three different blood vessels and as a result, homeostasis processes and functions are maintained within cells (Röder et al., 2016).  Minor errors which could influenced the color changes during the first 35 seconds include the changes in the stop watch measurements, room temperature and other factors such as accurate amounts of starting materials. Future designed experiments should monitor the color changes after every 10 seconds. Nonetheless, the overall final colors in the tests remained constant indicating the experiment was carried out within the required conditions and that the methodological approach is reliable and valid. Future tests should investigate the blood glucose concentration levels of the three different arteries.

Clinical Application

  The above result the essential role of insulin and glucose hormone in regulating blood glucose levels across various blood vessels. In essence, the results indicate the two hormones play an essential role in maintaining homeostatic processes. Clinically, changes in the final color changes of the blood glucose levels across the three different levels against the norm would indicate a disorder in the accompanying tissue.

References

• Fu, Z., Gilbert, E., & Liu, D. (2013). Regulation of insulin synthesis and secretion and pancreatic beta-cell dysfunction in diabetes. Current Diabetes Reviews, 9(1), 25–53. https://doi.org/10.2174/157339913804143225
• Godoy-Matos, A. F. (2014). The role of glucagon on type 2 diabetes at a glance. Diabetology and Metabolic Syndrome, 6(1), 91. https://doi.org/10.1186/1758-5996-6-91
• Röder, P. V, Wu, B., Liu, Y., & Han, W. (2016). Pancreatic regulation of glucose homeostasis. Experimental & Molecular Medicine, 48(3), e219. https://doi.org/10.1038/emm.2016.6