Snapshot A 15-year-old high school student presents with sudden weight loss, increased urination and increased thirst. He is an otherwise healthy individual who plays soccer on his schools team. On physical exam you see a lean young man with dry mucous membranes. Fingerstick glucose reveals a blood glucose of 469 mg/dL. Insulin Overview Synthesis/Release synthesized as proinsulin in β cells of pancreas proinsulin = insulin + C-peptide C-peptide secreted with insulin detection in serum is a mechanism to determine origin of hyperinsulinemia present with endogenous insulin, but absent with exogenous administration hyperglycemia, GH, and cortisol ↑ insulin while hypoglycemia and somatostatin ↓ insulin secretion released in response to increased glucose levels processed into ATP by oxidative phosphorylation ATP-sensitive potassium channel causes depolarization voltage sensitive calcium channel leads to calcium influx calcium leads to exocytosis of insulin-containing vesicles β agonists ↑ release of insulin while α agonists ↓ insulin secretion cleared by the kidneys dose adjustments may be required in patients with renal failure Function ↓ glucagon release by α cells of pancreas ↑ Na+ retention (kidneys) ↑ glycogen synthesis and storage ↑ triglyceride synthesis and storage major mechanism underlying weight gain with insulin treatment ↑ protein synthesis (muscles) recall babies of diabetic mothers are macrosomic ↑ cellular uptake of K+ recall used with glucose to treat hyperkalemia ↑ glucose transport into skeletal muscle and adipose see Glucose transport topic Pathology a patient with an insulinoma will secrete abnormally high levels of insulin as well as C-peptide and will not produce anti-insulin antibodies these patients will have severe hypoglycemia Glucagon Overview Production secreted by the pancreas (alpha cells) major stimulus for secretion is hypoglycemia major inhibition of secretion is hyperglycemia also inhibited by insulin and somatostatin Function increase blood glucose glycogenolysis gluconeogenesis stimulation of insulin release increase blood levels of other energy forms lipolysis ketone body production increase protein kinase A activity used in treatment of beta-blocker overdose Pathology a glucogonoma is a tumor that secretes excess glucagon leading to hyperglycemia as well as the characteristic rash of necrolytic migratory erythema
QUESTIONS 1 of 8 1 2 3 4 5 6 7 8 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.EC.15.75) Pancreatic islets were isolated from a healthy, non-diabetic donor to perform an experiment to look at insulin secretion inhibition. Compounds would be added to separate wells containing the islets bathed in a high glucose solution for one hour. After one hour, the supernatant would be collected, and the insulin content would be measured with an enzyme-linked immunosorbent assay (ELISA). Which of the following compounds would result in the least insulin secretion when added to the islets? QID: 106862 Type & Select Correct Answer 1 Dobutamine 8% (25/302) 2 Isoproterenol 15% (45/302) 3 Tolbutamide 7% (22/302) 4 Clonidine 38% (115/302) 5 Glyburide 17% (51/302) M 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (M1.EC.13.50) A researcher is tracing the fate of C-peptide, a product of preproinsulin cleavage. Which of the following is a true statement regarding the fate of C-peptide? QID: 100351 Type & Select Correct Answer 1 C-peptide is immediately degraded by the proteasome 8% (10/125) 2 C-peptide is packaged with insulin in secretory vesicles 63% (79/125) 3 C-peptide exits the cells via a protein channel 7% (9/125) 4 C-peptide is further cleaved into insulin 7% (9/125) 5 C-peptide activates an intracellular signaling cascade 11% (14/125) M 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK
All Videos (2) Login to View Community Videos Login to View Community Videos Insulin Overview Endocrine - Insulin and Glucagon D 2/16/2015 167 views 5.0 (5) Login to View Community Videos Login to View Community Videos Glucagon Endocrine - Insulin and Glucagon E 2/16/2015 76 views 0.0 (0) Endocrine | Insulin and Glucagon Endocrine - Insulin and Glucagon Listen Now 18:13 min 5/28/2021 128 plays 5.0 (1)