endocrine

Question 1

Signaling pways of endocrine hormones

1. cAMP
2. cGMP
3. IP3
4. Steroid receptor
5. Intrinsic tyrosine kinase
6. Receptor-associated tyrosine kinase

Answer 1

1. cAMP: FLAT ChAMP (FSH, LH, ACTH, TSH, CRH, hCG, ADH (V2), MSH, PTH) + calcitonin, GHRH, glucagon
2. cGMP: vasodilators (ANP, NO)
3. IP3: GOAT HAG (GnRH, Oxytocin, ADH (V1), TRH, Histamine, Angio II, Gastin) – think Ca release –> contraction
4. steroid receptor: Vit D, T3/T4, Estrogen, Testosterone, Cortisol, Aldo, Progesterone
5. Intrinsic Tyr Kinase: Insulin, IGF-1, FGF, PDFG, EGF –> MAP kinase pway (think growth factors
6. Receptor-associated Tyr kinase: PIG (ProlactIn, GH), immunomodulators (cytokines) —> JAK/STAT pway

Question 2

• Metformin
• rapid-acting insulin
• long-acting insulin

Answer 2

• biguanide: risk of lactic acidosis (don’t use in renal failure)
• Lispro, Aspart, Glulisine
• Glargine

Question 3

• Sulfonylureas
• Glitazones/Thiazolidinediones
• Acarbose

Answer 3

• Glyburide, Glimepiride, Glipizide: close K+ channel in B cell membrane –> depolarization –> Ca influx –> insulin release (** only drug that causes endogenous insulin release)
• Pioglitazone, Rosiglitazone: binds PPAR-gamma nuclear transcription regulator(increase insulin sensitivity) – SE= weight gain, edema, CHF, hepatotoxicity
• alpha-glucosidase inhibitor: inhibit inestestinal brush border disacchiridases – SE= GI disturbances (gas)

Question 4

• Exenatide, Liraglutide
• Linagliptin, saxagliptin, sitagliptin

Answer 4

• GLP-1/Incretin analogs: increase insulin, decrease glucagon
• DPP-4 inhibs: increase insulin, decrease glucagon release

Question 5

Hyperthyroid meds

Answer 5

• propylthiouracil: used in pregnancy
• methimazole
• both block thyroid peroxidase – PTU also blocks peripheral conversion of T4 to T3

Question 6

hypothyroid meds

Answer 6

• Levothyroxin and triidothyronine
• thyroxine replacement

Question 7

1. primary hyperparathyroidism
2. secondary hyperparathyroidism
3. hypoparathyroidism

Answer 7

1. high PTH, high Ca (hyperplasia, adenoma, carcinoma)
   
   1. osteitis fibrosa cystica: brown tumors
2. low Ca, high PTH (Vit D deficiency, renal failure)
   
   1. renal osteodystrophy: bone lesions due to increased PTH
3. low PTH, low Ca (surgical removal, autoimmune destruction)

Question 8

glucose uptake and insulin secretion

Answer 8

• Insulin binds Tyr kinase receptors –> induces gucose uptake(carrier-mediated) in insulin-dependent tissue –> gene transcription
  
  • GLUT4: skeletal mm and adipose tissue
• glucose enters beta cells –> increased ATP from glucose metabolism closes K+ channels –> cell depolarization –> voltage-gated Ca channels –> Ca influx –> insulin exocytosis
  
  • GLUT-2: Beta islet cells, liver, kidney, SI (insulin-independent transporters)

Question 9

Congenital adrenal hyperplasia

1. 17a-hydroxylase deficiency
2. 21-hydroxylase deficiency
3. 11B-hydroxylase deficiency

Answer 9

1. HTN only (XY: ambiguous genitalia, undescended testes; XX: lack secondary sex development)
2. Virilization only
3. HTN + virilization

all have enlarged adrenal glands due to elevated ACTH stimulation (from lack of negative cortisol feedback)