pack Flashcards
What is the structure of insulin?
51 amino acids
51 amino acids
2 polypeptide chains :A (21 aa) and B (30 aa)
linked together by 2 disulfide bridges
also contains an intramolecular disulfide bridge within A chain
What is the strucutre of preproinsulin and proinsulin and insulin?
Preproinsulin: Signal+ C peptide + insulin
Proinsulin: C peptide + insulin
Insulin: Insulin
Why is C-peptide a good way to measure insulin levels?
Secreted in equimolar amounts to insulin and C-peptide tends to stay in the body longer than insulin.
What is the mechanism of Sulfonylureas which are used to treat type II diabetes?
, oral agents used to treat type 2 diabetes, increase insulin secretion by closing ATP-sensitive K+ channels.
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Why does glucose taken orally induce a greater release of insulin than glucose that is given via IV?
Bc of the presence of GIP and GLP-1 in the GIT which increase the sensitvity of the B cells to glucose
What is the incretin effect?
It is the effect of increased insulin secretion due to oral glucose when comapred to IV glucose even if they result in the same amount of serum glucose.
What does insulin do to hormone senstive lipase?
Dephosphyrlates it causing its inactivation
What does insulin do in relation to adipocytes?
Increases the transport of glucose to adipocytes which provides the glycorl 3-phosphate substrate for TAG synthesis
What does insulin do in relation to lipoprotein lipase?
It activates it, activity increase degradation of chylomicrons release fatty acid FA will enter adipocytes and will be esterfied with glycerol phosphate increased TAG synthesis
What does insulin do in relation to protein sythesis?
What does insulin do in relation to lipoprotein lipase?
What does insulin do in relation to nuteriants mobilization?
Insulin inhibits the mobilization of nutrients
What are the three types of hypoglycemia?
Insulin-induced hypoglycaemia
in diabetic patients on insulin therapy
treatment by ingestion of carbohydrates or administration of glucagon (severe cases)
Postprandial hypoglycaemia
an exaggerated insulin release following a meal, prompting transient hypoglycemia with mild adrenergic symptoms
glucose level returns to normal even if the patient is not fed
Fasting hypoglycaemia
Due to reduction in liver’s production of glucose or increase in rate of glucose use in peripheral tissue
What are the have 2 overlapping glucose-regulating systems that are activated by hypoglycemia?
Glucagon release by a cells in pancrease
receptors in hypothalamus trigger secretion of catecholamines and release of adrenocorticotropic hormone (ACTH) and growth hormone by the anterior pituitary
What plays a role in the short term and long term management of blood glucose levels?
Short: Glucagon and epinephrine
Long (Transcriptional): Cortisol and GH
