Diabetes
Type 1
Insulin dependent
Childhood onset
Absolute deficiency of insulin
Autoimmune aetiology
Type 2
Relative insulin deficiency due to ↓ secretion (from pancreatic β cells) or insulin resistance or both
Insulin
Actions
Glucose uptake and utilization
Glycogen synthesis; inhibits glycogenolysis
Lipid synthesis; inhibits lipolysis
Protein synthesis; inhibits proteolysis
Mechanism
Binds to specific insulin receptor on cell membrane
Preparations
Aim is to provide basal level of background insulin with short acting boluses for meals
Long acting – insulin mixed with zinc or protamine for slow release. Glargine is a modified insulin analogue for slow release
Short acting – Actrapid, Humulin S
Biguanides
Metformin
Act only in the presence of residual endogenous insulin
Increase glucose uptake and inhibit hepatic gluconeogenesis
Reduce LDL and VLDL
Can cause lactic acidosis in renal failure
Sulphylureas
Gliclazide, glibenclamide
Promote insulin secretion from β-cells after binding to membrane receptors
Can cause hypoglycaemia
Renally excreted
Glitazones
Rosiglitazone
Reduce insulin resistance, ↑ glucose uptake and ↓ gluconeogenesis
plasma volume
