“ONE STEP AHEAD OF INSULIN”
SUBHAJIT HAZRA(3RD YEAR, 6TH SEMESTER)
(BACHELOR OF PHARMACY)
II. Insulin Biosynthesis.
III. Need for genetically engineered
V. Humulin synthesis.
VI. Clinical Pharmacology of Humulin.
VII. Advantage and disadvantage of humulin
Diabetris Mellitus –
Diabetes, often referred to by doctors as diabetes mellitus, describes a group of
metabolic diseases in which the person has high blood glucose (blood sugar).
Patients with high blood sugar will typically experience polyuria (frequent
urination), they will become increasingly thirsty (polydipsia) and hungry
Type 1 Diabetes - the body does not produce insulin. Approximately
10% of all diabetes cases are type 1.
Type 2 Diabetes - the body does not produce enough insulin for
proper function. Approximately 90% of all cases of diabetes worldwide are
of this type.
Symptoms: hyperglycemia,increasedurination,thirst,hunger,weight loss, weakness.
These can be managed by various treatments, one of which is insulin treatment.
II. INSULIN PRODUCTION .
Insulin is produced by the β cells of islets of langerhans of pancreas.
The gene(Human Insulin Gene) responsible for this protein synthesis is located on chromosome 11.
The insulin mRNA is translated as a precursor called preproinsulin, removal of its signal peptide
during insertion into the endoplasmic reticulum generates proinsulin.
Proinsulin consists of three domains: an amino-terminal B chain, a carboxy-terminal A chain and a
connecting peptide in the middle known as the C peptide. Within the endoplasmic reticulum
specific endopeptidases excise the C peptide, thereby generating the mature form of insulin.
Insulin and free C peptide are packaged in the Golgi apparatus which accumulate in the cytoplasm.
When the beta cell is appropriately stimulated, insulin is secreted from the cell by exocytosis and
diffuses into islet capillary blood. C peptide is also secreted into blood, but has no known
β cells preproinsulin translocation proinsulin
insulin golgi apparatus
III. NEED FOR GENETICALLY
ENGINEERED INSULIN (HUMULIN).
In the 1920s ,physicians began giving insulin purified
from the pancreas of pigs(porcine) and cows(bovine) to
the diabetic patients as porcine and bovine insulin were
similar to human insulin.
As their was a slightly difference in the human and
animal produced insulin it resulted in the production of
antibodies against the animal’s insulin in the patient’s
This in turn resulted in inflammatory responses at the site
Thus evidenced from various clinical cases led
researchers to synthesize humulin(Genetically
It was 1st prepared by Eli Lily &Co.(Humulin N / R).
Humulin R® U-500 is a polypeptide hormone structurally
identical to human insulin synthesized through rDNA
technology in a special non-disease-producing laboratory
strain of Escherichia coli bacteria.
Humulin R® U-500 is a sterile, clear, aqueous and colorless
solution that contains human insulin (rDNA origin)
Humulin R U-500 is for subcutaneous injection only and
should not be used intravenously or intramuscularly.
short acting intermediate acting
(takes 30 min.to act) (takes 2 to 4 hr. to act)
e.g: Humulin S Humulin N(Neutral Protamine Hagedorn)
V. HUMULIN SYNTHESIS
Synthesis of Humulin is a 2 Step Reaction –
Step 1 of Synthesis – Synthesis of r-dna and its introduction in vector.
At first, the DNA chains carrying the nucleotide sequences specifically for A & B chains, are
This requires 63 nucleotides to synthesize A chain , 90 nucleotides for B chain and a terminator
codon to terminate synthesis when required.
Also,an anticodon methionine , which is added at the beginning of the sequence to distinguish
humulin from the other bacterial proteins is required.
The synthetic A &B chain are then separately inserted into the plasmid.
Step 2 of Synthesis – Clonning of r-dna in host (E.coli )
The r-plasmids are then introduced into the E.coli cells,where the insulin gene is expressed as it
replicates with the enzyme in the cell undergoing mitosis.
The protein which is formed, consists partly of β galactosidase, joined either to A or B chain of
insulin, from where the A &B chains are extracted and purified.
The two chains are mixed and reconnected in a reaction that forms the disulphide cross bridges,
resulting in pure humulin.
Due to the complexity in it’s (humulin’s) purification technique from the bacteria, now a days we use
yeast cells (eukaryotic) as the vector which secreate the whole humulin molecule with perfect 3D
FIG 2 - STEP 1 OF SYNTHESIS – SYNTHESIS OF R-DNAAND ITS INTRODUCTION IN
STEP 2 OF SYNTHESIS – CLONNING OF R-DNA IN HOST (E.COLI )
VI. CLINICAL PHARMACOLOGY OF HUMULIN.
Administered insulin, including Humulin R U-500, substitutes for
inadequate endogenous insulin secretion and partially corrects the
disordered metabolism and inappropriate hyperglycemia of diabetes
mellitus, which are caused by either a deficiency or a reduction in the
biologic effectiveness of insulin.
When administered in appropriate doses at prescribed intervals to
patients with diabetes mellitus, Humulin R U-500 restores their ability to
metabolize carbohydrates, proteins and fats.
As with all insulin preparations, the duration of action of Humulin R U-
500 is dependent on dose, site of injection, blood supply, temperature,
and physical activity.
The time course of action of any insulin may vary considerably in
different individuals or at different times in the sameindividual.
VII. ADVANTAGES & DISADVANTAGES OF HUMULIN
a) Humulin could be created in large amounts and at relatively low
b) It doesn’t produces inflammatory response in diabetic patients.
a) Some patients have claimed that on switching to human insulin
from animal insulin, resulted in increased risk of hypoglycemia.
b) But, research study have found no significant difference in the
frequency of hypoglycemia between users of two different types of