Diabetes
Mellitus
Contents
• Diabetes
Mellitus
• Normal
insulin physiology
• Type I
Diabetes Mellitus
• Type II
Diabetes Mellitus
Objectives
At the end of this PDF Notes, student will be able to
• Define the term “Diabetes Mellitus”
• Classify Diabetes mellitus
• Describe the normal physiology of Insulin
• Explain the etio-pathogenesis of type I DM
• Explain the etio – pathogenesis if type II DM
Diabetes Mellitus (DM)
• Chronic
metabolic disorder
• Characterized
by hyperglycemia due to deficiency of insulin or defective response of tissues
to insulin
Classification
of Diabetes Mellitus
Primary (idiopathic) DM
• Primary
disorder by itself
• Type
– I (Insulin dependent DM/ IDDM)
• Type
– II (Non- Insulin dependent DM/NIDDM)
Secondary DM
• Due
to identifiable cause – pancreatitis, endocrine disorder
• Gets
corrected/ reversed when primary disorder is controlled
Etio-pathogenesis
of Diabetes Mellitus
Normal Insulin
Physiology
Regulated by 3
processes
• Glucose production by liver
• Uptake and utilization of glucose by
peripheral tissues
• Insulin secretion
Normal
Insulin Physiology
• Pre
proinsulin – precursor for insulin
• Synthesized
from insulin mRNA in rough ER of pancreatic β cells
• Delivered
to golgi complex
• Series
of proteolytic cleavage
• Pre
proinsulin to pro insulin
• Finally
to mature insulin + C- peptide
• Mature
insulin + C- peptide – stored in equimolar concentration in secretory granules
• Glucose
– important stimulus that triggers the syntheis & release of insulin
• Glucose
taken up by pancreatic β
cells through GLUT-2
• Immediate
release of insulin
• Phase
I of insulin secretion
• Released
insulin is taken up by the insulin receptors present on the surface of tissues
• Series
of intracellular reactions
• Activation
of insulin dependent GLUT 4 transporter
• Uptake
of glucose
Any defects in the above steps – Diabetes mellitus
Action of Insulin
