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Showing posts with label insulin. Show all posts
Showing posts with label insulin. Show all posts

What are different Insulin preparations?

Various insulin preparations are available based on onset and duration of action.They can be short acting or long acting.

1. Lispro
Short acting group insulin.
28th lysine & 29th proline in B chain is reversed by recombinant DNA technology.
It has less tendency to form local aggregates.
Lispro has less incidence of hypoglycemia.
Absorption is delayed with NPH insulin, but not with ultralente.
Injected just before or after food.

2. Aspart
This is the shortest acting group of insulin.
This can be protaminated to extend the duration of action.
Aspart + protaminated aspart = Biphasic insulin.
Can be used as 30/70 insulin.
Used in pen devices.

3. Glulisine
Short acting insulin.
Not commonly available.
Asparagine @ B23 position is replaced by Lysine, lysine at B29 replaced by Glutamic acid.

4. Isophane / NPH insulin
Biphasic isophane available as pen devices.(Mixtard 30 novolet).
Most popular in 30/70 combination.
Lente available as Monotard.
Can be used once daily.
Ultara lente not available now.

5. Glargine
Asparagine at 21 replaced by Glycine.
2 Arginine residues added to c terminus of B chain.
Longest acting.
No peak in action,smooth sustained effect.
Less chance of hypoglycemia.
Not stable at room temp.
Cant mix with others.

6. Detemir
Myristic acid is bound to B29 lysine.
Long acting.
No local aggregate is formed.
Bound to albumin.
Less chance of hypoglycemia.

7. Degludec
Newer Long acting.
Effective at physiological pH.
Can be mixed with other insulins.

Regulation of insulin secretion (Chemical,Hormonal and Neural factors)

Insulin was discovered in 1921 by BANTING and BEST.  
It is a peptide hormone composed of 51 amino acid residues.
Insulin has a molecular weight of 5808.
Insulin is synthesized in the beta cells of the pancreas.
The name insulin comes from the Latin word insula for "island
Insulin is initially produced as a single polypeptide chain, preproinsulin which contain 110 amino acid residue.
1unit of insulin is secreted per hour under basal conditions.

Regulation of insulin secretion is by Chemical, hormonal and neural factors
Chemical factors

  1. Glucose, amino acids (arginine, etc.), fatty acids, and ketone bodies stimulate  the secretion of insulin. 
Hormonal factors

  1. Glucagon increase insulin release
  2. Somatostatin inhibits the insulin release
  3. Growth hormone,Thyroid hormone,cortisol produce  hyperglycemia.

Neural factors

  1. Alpha2 stimulation decreases insulin secretion.
  2. B2 stimulation increases the insulin level.
  3. Cholinergic stimulation increases insulin.