Lab 25 Endocrine Physiology I
ranges of fasting blood glucose levels
- 110 mg/dl is normal - 110-126 mg/dl is pre diabetic - over 126 is diabetic
Q10: In the thryoidectomized rat was there any change in metabolic rate when you injected propylthiouracil? Explain.
- No change - No thyroid gland, no thyroxine production, nothing for PTU to block
Q9: In the thryoidectomized rat was there any change in metabolic rate when you injected TSH? Explain.
- No change in MR - no thyroid gland present to release T3 and T4 - no thyroid gland to stimulate and no thyroxine
glucagon is secreted by
- alpha cells of the islets of langerhans in response to decreased blood glucose level - target tissues
metabolic rate
- amount of energy required for necessary body functions
insulin is secreted by
- beta cells of the islets of langerhans of the pancreas in respond to increased blood glucose level
Type 1 diabetes
- body does not produce insulin - caused by autoimmune disorder that destroyed beta cells - high glucose levels because of no insulin
Q1: How do the baseline metabolic rates of the thyroidectomized and hypophysectomized rats compare with the normal rat? Explain any differences.
- both have lower MR than normal rat - thyroidectomized rat has no thyroid, no T3 and T4, decreased MR - hypophysectomized rat has no pituitary gland, no TSH, no thyroxine, decreased MR
Type 2 diabetes
- cells develop insulin insensitivity
Q14: What is the purpose of barium hydroxide?
- dissolves proteins and cell membranes - so glucose readings can be read better
propylthiouracil
- drug that blocks formation of thyroxine by preventing bind of iodine to tyrosine
what causes a goiter
- excess TSH secretion or reduced TH secretion
factors that control MR
- gender: males have higher MR - age: MR decreases with age
endocrine system is composed of
- glands that that secrete hormone into the bloodstream to influence distant tissues and organs
thyroxine (TH)
- hormone made by our thyroid gland that increases MR
what is the process involving the release of thyroxine?
- hypothalamus releases TRH - anterior pituitary releases TSH - TSH goes to thyroid gland - TSH simulates follicular cells to release thyroxine
what are the three organs needed to release thyroxine?
- hypothalamus, anterior pituitary gland, and thyroid gland
what hormones maintain blood glucose level?
- insulin and glucagon
antagonistic characters of hormones
- insulin lowers blood glucose level after a meal - glucagon raises blood glucose level during starvation
Q13: In the hypophysectomized rat was there any change in metabolic rate when you injected propylthiouracil? Explain.
- no change - no pituitary gland, no TSH - thyroid goes not produce thyroxine, nothing for PTU to block
Q2: Which of the rats developed a goiter after injection with thyroxine? Explain.
- none - thyroxine does not affects hypothalamus and anterior pituitary gland - TSH is what causes goiter, not the increase in thyroid hormone
Q3: Which of the rats developed a goiter after injection with TSH? Explain.
- normal and hypophysectomized rat - need thyroid gland for goiter - increase TSH will cause thyroid gland to grow
Q4: Which of the rats developed a goiter after injection with propylthiouracil? Explain.
- normal rat - both thyroid and pituitary gland present and propylthiouracil blocks thyroxine formation and negative feedback does not occur - TSH increases
goiter
- overgrowth of thyroid gland
Q16: Are any of your patients pre-diabetic? What advice would you give them?
- patient 2 and patient 4 - low carb diet, exercise, and lose weight - monitor glucose levels
Q17: Are any of your patients diabetic? What advice would you give them? What course of treatment should they follow?
- patient 3 and patient 5 - exercise more, limit sugar and carb intake - glucose lowering drugs, go on insulin therapy
standard curve
- plot of known values used to determine unknown values
Q15: What is the purpose of heparin?
- prevents blood clots, which would interfere with clear glucose readings
thyroid stimulating hormone
- secreted by anterior pituitary gland
thyrotropin releasing hormone
- secreted by hypothalamus
hypophysectomy
- surgical removal of pituitary gland
thyroidectomy
- surgical removal of the thyroid gland
target for glucagon
- target tissues: liver and adipose tissue
What are the three rats given?
- thyroxine, TSH, propylthiouracil
target cells of insulin
- to insert GLUT-4 glucose carrier into their cell membrane to take glucose out of blood
Q5: In the normal rat was there any change in metabolic rate when you injected thyroxine? Explain.
- yes, MR increased - T3 and T4 increased, MR will increase - thyroxine should increase MR because goes directly to target cells
Q6: In the normal rat was there any change in metabolic rate when you injected TSH? Explain.
- yes, MR increased - T3 and T4 went up, TSH stimulates secretion of TH
Q12: In the hypophysectomized rat was there any change in metabolic rate when you injected TSH? Explain.
- yes, MR increased - TSH makes thyroid gland to grow and release thyroxine
Q11: In the hypophysectomized rat was there any change in metabolic rate when you injected thyroxine? Explain.
- yes, MR increased - more thyroxine then increase in MR regardless of condition of rat
Q8: In the thryoidectomized rat was there any change in metabolic rate when you injected thyroxine? Explain.
- yes, MR increased - thyroxine goes to target cells and increases MR
Q7: In the normal rat was there any change in metabolic rate when you injected propylthiouracil? Explain.
- yes, decrease in MR - PTU blocks formation of TH, not producing as much thyroxine, decreases MR