Post Lab Question Experiment 5 a. List the effect of each of the following hormones on blood glucose and the mechanism producing the effect. HORMONE
BLOOD GLUCOSE EFFECT
Insulin
The blood glucose level will be decreased
Adrenaline
The blood glucose level increased
Glucagon
The blood glucose level increased
Growth Hormone
The blood glucose level increased
Cortisol
The blood glucose level increased
MECHANISM When the blood glucose level is high, the beta cells were stimulated and released insulin. In response to insulin, the muscle cells, red blood cells and fat cells absorb glucose out of the blood having the net effect of lowering the high blood glucose level into the normal range Adrenaline will direct the liver to breakdown the glycogen and release glucose in the bloodstream while it will direct the muscle to breakdown glycogen into glucose but instead of releasing the glucose, the muscle will hold on it and use it as immediate energy When the blood glucose level falling, the alpha cells at the liver will stimulated and will release the glucagon. The glucagon will acts on hepatocytes to activate the enzymes that depolymerize glycogen and release glucose Supress the release of insulin which will make the blood glucose level higher The cortisol will tapping into protein stores by gluconeogenesis in the liver
b. How are the levels of insulin and glucagons regulated in the body? Insulin and glucagon are blood glucose that regulated in large measure by two pancreatic hormones. Both are peptides secreted by the pancreas that also act as an endocrine function in response to changes in blood glucose outside of its normal physiological range and both cause biological changes in distant target cells by binding to protein receptor molecules embedded in the plasma membrane. Insulin causes a wide range of responses including gene regulation, changes in intracellular ion concentration and changes in fuel metabolism. In three major insulin targets that are skeletal muscle, adipose, and liver, insulin act as glucose utilization. In these tissues, insulin stimulates glucose uptake from the blood and encourages glucose metabolism in three major pathways: 1) breakdown by glycolysis and cell respiration for ATP production, 2) uptake of “extra” blood glucose in order to store it as glycogen in the liver and skeletal muscle and 3) the conversion of glucose into triglycerides (white fat) in adipocytes and the liver by lipogenesis for long-term energy storage. When blood glucose increases (after eating) the pancreas responds by secreting insulin into the blood. Then, insulin stimulates blood glucose uptake by body tissues, which functionally will reduce blood glucose levels. When the muscles and liver take up blood glucose and extra blood glucose not needed for cell metabolism can be converted to a storage form of glucose called glycogen (a process called “glycogenesis”). Insulin is a hormone with a relatively short half-life, and it is 50% degraded within If blood glucose drops (after skipping a couple of meals) the pancreas respond by secreting glucagon, which stimulates the liver to break down glycogen stores into free glucose (a process termed “glycogenolysis”) and release glucose into the blood, functionally increasing blood glucose levels. Thus, regulation of blood glucose to within a normal range involves both the pancreas and the liver.
c. What causes the ‘insulin shock’ seen when an overdose of insulin is given to an organism? The causes of “insulin shock” seen when an overdose of insulin is given to an organisms is having too much insulin in the blood can lead to having too little glucose. If the blood sugar falls too low, the body no longer has enough fuel to carry out its regular functions. In insulin shock, the body becomes so starved for fuel that it begins to shut down. The overdose of insulin can be due to excessive insulin dose, it happened when patient forget or may be not aware of the recommended units of insulin to be injected. As a result he may inject insulin that is more than the required amount. Then, the mismatched meal timings also one of the factors, it happen when patient not eating food after taking insulin dose and the blood sugar may drastically reduce in the body and lead to condition called hypoglycemia. Lastly, patient accidentally injected wrong type of insulin. For example instead of injecting long acting insulin, he may inject short or rapid acting insulin. d. Why is there an increase in urine output (diuresis) in diabetes mellitus? Diabetes mellitus patient can resulting in hyperglycemia (elevated blood glucose) if not treated well. This is the primary cause of excessive urine production or urine output (diuresis). When it passes through the kidneys for filtering, excess glucose in blood will accumulated in the tubules within the kidneys. Once there, it blocks the reabsorption of water, leading to an increased concentration of water in the bloodstream. The kidneys then act to remove the excess water, causing increased urine production and increased frequency in urination. e. Why does a person who has diabetes mellitus have more acidic urine? When insulin is deficient and the cells cannot metabolize glucose for energy, instead, your body is forced to metabolized fat and convert fat into energy. The increased metabolism of fats releases into the blood large quantities of ketone bodies (e.g., acetone), which are intermediate products of fat breakdown. These are excreted in the urine. Ketone bodies are acidic and their accumulation will cause a drop in blood pH; the diabetic becomes acidotic.
f. Some diabetics control their blood glucose level by ingestion tablets rather than by receiving injections of insulin. How do these tablets work, and who may use them? Ingestions tablets known as oral hypoglycaemics or antihyperglycaemics are used to treat type 2 diabetes mellitus. Type 1 diabetics’ patient will usually go for insulin injections. There are a number of different types of oral hypoglycaemics available for treating type 2 diabetes, and they work in different ways. They may be used on their own and some can be used in conjunction with each other, or with insulin. There are various types of oral medicine that can be used to control blood sugar in type 2 diabetes like Biguanides (metformin), Sulfonylureas, Glitazones (sometimes called thiazolidinediones, Meglitinides, Gliptins (DPP-4 inhibitors which also available in combination with metformin, Alpha-glucosidase inhibitors; Acarbose (Glucobay) and Sodium-Glucose Transporter-2 Inhibitors. Oral medicines work in five basic ways to lower blood glucose in Type 2 diabetes: 1. Reducing insulin resistance: metformin and glitazones Metformin works mainly by reducing the amount of glucose produced by cells in the liver, and by increasing the sensitivity of muscle cells to insulin. This enables the cells to remove sugar from the blood more effectively. It also reduces the amount of sugar produced by cells in the liver and reduces the absorption of glucose from the gut after eating. Pioglitazone works by increasing the sensitivity of liver, fat and muscle cells to insulin. This medicine may also preserve the function of the beta cells in the pancreas and reduces the amount of glucose produced by the liver. 2. Stimulating insulin release: sulfonylureas and meglitinides The sulfonylureas and meglitinides work mainly by stimulating the beta cells in the pancreas to release more insulin. Meglitinides start to work more quickly and have a shorter effect than the sulfonylureas. They are taken to enhance insulin production during meals.
3. Slowing the absorption of sugar from the gut: acarbose Acarbose works by blocking the action on breaking down carbohydrates into simple sugar molecules by enzyme alpha-glucosidase that is found in the lining of the gut. This delays the absorption of sugar molecules from the gut, so that high peaks of blood glucose after eating are avoided. 4. DPP-4 inhibition: gliptins DPP-4 inhibitors, called gliptins prevent the breakdown of glucagon-like peptide-1 (GLP-1), which allows more insulin to be produced after meals. GLP-1 stimulates insulin release from the pancreas after meals. This reduces post-prandial hyperglycaemia (increased blood glucose levels after meals). The gliptins also suppress the release of another hormone from the pancreas called glucagon, which works against insulin. This further action of these new drugs improves glucose control. 5. Increasing excretion of glucose in urine: gliflozins Gliflozins are a relatively new class of medicines that lower blood sugar by increasing its excretion in the urine. Gliflozins works in the kidneys. Normally, when the kidneys filter and clean the blood, glucose is filtered out of the blood at the same time. The glucose is then reabsorbed back into the blood by a mechanism called the sodium-glucose co-transporter 2 (SGLT2). The kidneys normally reabsorb glucose back into the blood even when the levels of glucose in the blood are too high, as in diabetes. Gliflozins works by inhibiting the SGLT2 transporter. This allows excess glucose to be filtered out of the blood and excreted in the urine. g. Define the following terms: Glycogenolysis Glycogenolysis is the process where muscle or liver cells break down glycogen to glucose and use the glucose as an energy source. Gluconeogenesis The metabolic process in which glucose is formed, mostly in the liver, from non-carbohydrate precursors
Ketonemia Ketonemia is the presence of an abnormally high concentration of ketone bodies in the blood. Hyperglycemia Hyperglycemia, or high blood sugar (also spelled hyperglycaemia or hyperglycæmia) is a condition in which an excessive amount of glucose circulates in the blood plasma.
