Assignment on endocrinology PDF

Diabetes 1
ENDOCRINOLOGY ASSIGNMENT ON TYPE 2 DIABETES
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Diabetes 2
Answer to question 1
An oral glucose tolerance test is used to detect and confirm diabetes in patients suspected
to have the disease. It measures one’s body response to sugar/glucose (D'Souza et al
(2016)). It’s usually used to screen for diabetes type 2. A modified version of the same
can be used to diagnose gestational diabetes. The tolerance test is taken for a period of
two hours after ingesting glucose. In the procedure, one takes a solution that contains a
defined amount of glucose and the levels in blood are tested before, within 1 hour and
after two hours of intake of the solution. Two hours later the blood glucose levels are
tested. The expected results for a healthy person would show a normal blood glucose
level of between 3.2mmol/l to 7.8mmol/l which is the normal standard range for a
random blood sugar test. As stated by Pedersen et al (2016). The blood sugar levels
should not exceed 7.8mmol/l after the 2 hour mark for a healthy person. The fasting
blood sugar levels of a healthy person should also range between 3.9 to 6.1mmol/l when
tested. However in a pre-diabetic state the blood sugar levels range between 7.8 and
11mmol/l after the two hour mark indicating impaired glucose tolerance. The expected
results from our patient would show a blood sugar level that exceed 126mg/dl in the
fasting state and a random blood sugar levels that exceed 200mg/dl after the two hour
mark which is diagnostic for diabetes. This is because of the characteristic symptoms that
the patient had such as blurred vison and frequent urination suggestive for diabetes and
the test would be a confirmation of the disease
Answer to question 2
Insulin is a protein in nature. It is made of a dimer composed of two chains of amino
acids which are held together by bonds of disulphide. It is made of 51 amino acids. It is
made and released from beta cells of the pancreas. As echoed by Craft et al (2016), the
levels of glucose in blood are kept within range by a loop mechanism (negative feedback)
in an attempt to keep the body systems in balance. The feedback mechanism operates in a
manner such that when the blood glucose levels are high, the body looks for ways of
reducing these levels to normal. When levels of blood glucose rise, either from the
digestion of a meal or from glycogen-glucose conversion, insulin hormone is released
from a glandular group of cells within the pancreas called Langerhans where the b cells
reside. The levels of glucose in blood are detected directly by beta cells of the pancreas.
There are other causes of increase in blood sugar levels. These include the hormone
adrenaline, steroids, infections and trauma (Shungin et al (2015)). GLUT 2 transporters
form the transport channels where glucose enters the beta cells. This glucose is then
phosphorylated by kinases and is converted to pyruvate in the cytoplasm. The breakdown
of glucose involves a series of steps in a process called glycolysis into two molecules of
pyruvate. The broken down glucose in form of pyruvate enters the mitochondria and is
further broken down to water and carbon (IV) dioxide whereby ATP is formed by

Diabetes 3
addition of phosphate molecules. The ATP from the mitochondria migrates into the
cytoplasm, where it inhibits ATP sensitive potassium channels, reducing potassium
efflux. This causes increased positive charge as potassium molecules are cations. This
causes depolarization of the beta cell and calcium enters the cell via voltage gated
calcium channels (Fajans et al (2016)). The calcium entry causes the release of secretory
granules containing insulin hence triggering the release of insulin from b cells. The liver
has several functions in the body and is involved in glucose metabolism. There are
several processes that occur in the liver as pertains glucose and these include the
formation of glucose, (gluconeogenesis), the breakdown of glycogen, (glycogenolysis)
and glycogen synthesis. Insulin being a hormone involved with glucose regulation
therefore affects the liver. It causes the liver to convert excess glucose into glycogen and
most of the body cells mainly the muscle cells and those found in fat tissue to uptake the
glucose via GLUT 4 channels leading to low levels of glucose in blood. Insulin is also
involved in protein synthesis where it encourages conversion of circulating amino acids
into protein. Examples of such amino acids are leucine and arginine. A high level of these
compounds thereby stimulates secretion of insulin as they act in a similar manner to
glucose by generation of ATP once they are metabolized. This leads to closure of
potassium sensitive pumps in the beta cells causing insulin release. (Humphrey et al
(2015). Hypoglycemia (low blood sugar levels) on the other hand reduces insulin release.
According to Sandler et al (2017), low blood glucose levels at the same time triggers the
release of four hormones which counter the activities of insulin of which the principle
hormone that counteracts this effect is glucagon. These hormones work hand in hand to
ensure that glucose levels in blood are increased to normal hence homeostasis is achieved
Answer to question 3
The receptor pf insulin is a complex made of alpha and beta subunits. It is activated by
either insulin or insulin like growth factors. As stated by Canfora et al (2015), binding of
insulin or insulin like growth factors to the alpha subunit leads to a change in
arrangements resulting into down cascade where tyrosine molecules within the beta
subunit are phosphorylated. The resulting pathway causes a series of downward cascade
involving a number of enzymes and amplification sequences that lead to glucose storage.
Insulin stimulates glucose uptake by cells including myocytes and cells found in fat
tissues (Anhê et al (2015)). It does so by inducing changes that lead to the migration of a
transporter of glucose called GLUT 4 from the intracellular storage to the plasma
membrane. Enzymes involved in the process including P 13 and kinase and AKT are
known to play an essential role in GLUT 4 movement. According to Jung et al (2014),
the activation of the receptor complex leads to a series of downward activation of a gene
encoded protein (Cbl) through phosphorylation attached to second messenger CAP. The
complex formed between the two proteins then translocate to lipid layers in the cell
membrane. The former (Cbl) after this binds crk associated with an exchange factor C3G.
The exchange factor then activates components of a larger family specifically tc10 that