| Class | Insulin |
|---|---|
| Chemistry |
Peptide hormone: A complex of regular human insulin and protamine |
| Routes of administration |
Subcutaneous |
| Absorption |
Essenially zero oral bioavailability. Absorbed from subcutaneous depot: onset of clinical effect is within about 1.5-4 hrs |
| Solubility |
Insulin-protamine complex precipitates at physiological pH, i.e. becomes insoluble. Monomeric insulin is highly soluble, and slowly dissociates from this coimplex. |
| Distribution |
VOD= 0.44 L/kg; minimally protein-bound |
| Metabolism |
Over 50% metabolism by the liver, 30% by the proximal tubule in the kdiney, the rest by skeletal muscle and adipose tissue. Ligand/receptor complex is endocytosed and degraded after it binds its receptor. |
| Elimination |
Only 1% of the free drug is eliminated in the kidney |
| Time course of action |
Onset of effect = 1.5-4 hrs, peak activity at 6-14 hrs, duration of action apporoximately 16-24 hrs |
| Target receptor |
Insulin receptor, a transmembrane receptor with an intracellular tyrosine kinase domai, which uses the PI3K secondary messenger pathway for intracellular signalling |
| Mechanism of action |
Increases the exocytosis and cell surface expression of GLUT4 transport proteins, which results in the uptake of glucose into insulin-sensitive tissues. Also multiple metabolic effects: decreased glycogenolysis and increased glycogen synthesis in the liver, decreased free fatty acid mobilisation by fatty tissue, increased lipoprotein lipase activity, decreased protein catabolism, positive inotrpic effects, and decreased releae of glucagon |
| Clinical effects |
|
| Literature reference |
Hagedorn, 1937 (yes) |
| CICM details of understanding | Level 1 |
| Mentioned around Deranged Physiology | |
| Related SAQs |