You have asked a very interesting question, and
one that I am not very familiar with myself...so I
had to do some searching around the web for the
answer. Let me share what I have learned so far,
and hopefully this will help answer your question.
As you probably know, scientists have found
that diabetes is actually an auto-immune disease
(i.e., the immune system sends out lymphocytes to
attack cells in your body that it mistakes for
invaders/foreign substances.) Other auto-immune
diseases include AIDS, which, like diabetes, is
thought to be triggered by a virus. In the case of
AIDS, the HIV retrovirus is a known causative
agent, but for Diabetes it hasn't been discovered
yet. They are working hard on this though, as I
gather from the medical websites I visited.
There are 2 types of diabetes: Type 1
diabetes mellitus and Type II diabetes
mellitus. Type I is referred to an
insulin-dependent diabetes (IDD) (your body has
stopped making the hormone insulin), and Type II
is called non insulin-dependent diabetes (NIDD)
(your body still makes insulin but at a much
reduced or sluggish rate compared to most people).
This next part I got from a the University of
California Berkeley Molecular and Cellular Biology
Class website taught by Dr. Paola Timiras:
I have edited parts of it that might be of
interest to you, but be sure to go to this website
for more information (and to see what a college
class is like!)
"The pancreas... is both an endocrine and an
exocrine gland. The exocrine functions are
concerned with digestion. The endocrine function
consists primarily of the secretion of the two
major hormones, insulin and glucagon. Four cell
types have been identified in the islets (these
are cells called the "islets of Langerhans"
in the pancreas), each producing a different
hormone with specific actions:
* A cells produce glucagon; * B cells produce
insulin; * D cells produce somatostatin; and * F
or D1 cells produce pancreatic polypeptide.
These hormones are all polypeptides. Insulin
is secreted only by the B cells whereas the other
hormones are also secreted by the gastrointestinal
mucosa and somatostatin is also found in the
"Question: what do all these hormones
produced by A, B, C, and D cells in the islet of
Langerhans in the pancreas do in your body?
Okay onward.... This next set of quotes came
from another website by the Medical Library at the
University of Utah Medical School.
Let see what happens to the islets of
Langerhans once the autoimmune reaction is
triggered in a person's body... "Type I: The
islets of Langerhans are destroyed in type I
diabetes mellitus. This occurs probably as a
consequence of a genetic susceptibility, followed
by the onset of autoimmune destruction triggered
by some environmental factor such as a viral
infection. Heavy lymphocytic infiltrates appear in
and around islets. The number and size of islets
are eventually reduced, leading to decreased
insulin production and glucose intolerance.
Type II: The islets of Langerhans are normal in
number or somewhat reduced with type II diabetes
mellitus. Fibrosis and deposition of amylin
polypeptide within islets are most characteristic
of the chronic states of type II diabetes." From
this information, I have to conclude that for Type
1 diabetes (IDD), the actual insulin -producing B
cells are destroyed (along with all the other
types of cells in the islets of Langerhans) when
the lymphocytes mistakenly attack them. In this
case, the rough endoplasmic reticulum (RER) would
simply be broken down with the rest of the cells
and recycled (much like white blood cells clean up
damaged cells near a skin wound). However, it
seems like with Type II diabetes (NIDD), the
islets are not necessary destroyed all at once (as
in Type I), but their functionality is hindered by
"fibrosis and deposition of amylin polypeptide"
(protein-like scar tissues that attaches to the
cells) over time.
Something about these compounds causes the
cells to die after a while (decreased exchange
of gases? decreased energy for respiration?
Scientists are still working on that part!). This
is why some Type II diabetes patients require
insulin injections after they have had the disease
for many years, as opposed to Type I diabetes
patients that have to have insulin injections
immediately after developing the disease.
Question: Do you know how doctors
help patients control Type 1 and Type II diabetes?
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