Islet cell structure α cell : glucagon β cell : insulin δcell : somatostatin δcell α cell β cell

Principal actions of insulin Its net effect is to promote the storage of carbohydrate, protein and fat. It is therefore appropriately called the “ hormone of abundance”. 70 mg/dl 300 mg/dl (Glucosurea)

Consequences of insulin deficiency NORMAL DIABETIC

Disturbances in protein metabolism INSULIN DEFICIENCY

Dehydration

Insulin lipodystrophy

Chronic neuropathy: Trophic ulceration

Gangrene

Gangrene with infection

Insulin allergy

Glucagon Synthesis and secretion of glucagon ⊕ ⊕ ○ Glucagon ⊕ Amino acids ⊕ Glucose FFA Ketoacid ○ Glucagon ⊕

Actions of glucagon Plasma: Glucose ↑ Amino acids ↓ Free fatty acids↑

Diabetic retinopathy – Microvascular complication

Hormones of the pancreatic islets Pancreas, Liver & Nutrient Liver : the central organ in nutrient traffic

Endocrine regulation of carbohydrate metabolism Insulin Glucagon Somatostatin --- inhibit the secretion of insulin & glucagon Epinephrine --- cyclic AMP increased, [Ca+2] increased  hepatic glucose output increased. 5. thyroid hormone : (1) increases the absorption of glucose from the intestine (2) cause hepatic glycogen depletion (3) accelerate the degradation of insulin 6. glucocorticoids --- diabetogenic effect 7. growth hormones --- inhibition of glucose phosphorylation  decrease utilization

In Summary Insulin Glucagon Is released by B-cells in the Islets of Langerhans in the pancreas. Responds to high levels of blood sugar; is released when someone has a meal and needs to store extra energy. Lack of insulin or response to insulin leads to diabetes. Is released by a-cells in the Islets of Langerhans in the pancreas. Responds to low levels of blood sugar; is released when someone hasn’t eaten or requires extra energy Basically, glucagon is the opposite of insulin.