LAB ONE: Exercise 4 – Endocrine System
Activity 1: Metabolism and Thyroid Hormone
1. The normal rat had the fastest basal metabolic rate.
2. The metabolic rates differed between the normal rat and the surgically altered rats because the surgically altered rats didn’t have a thyroid or pituitary gland and therefore, the normal rat had a faster basal metabolic rate. The results turned out to be the way I predicted them to be. 3. T3 and T4 would be missing in the animal’s blood.
4. I would expect to see a decrease in hormone levels since the hypophysectomized animal cannot secret ay TSH. Part 2:
5. The normal rat’s BMR increased.
6. The thyroidectomized rat’s BMR increased. However, in comparision to the normal rat, the thyroidextomized rat’s BMR was lower than the normal rat (meaning the normal rat still had a larger BMR). The dose of thyroxine in the syringe was therefore too small. 7. The hypophysectomized rat’s BMR increased as well, and once again, the BMR of the normal rat was still larger and so the dose was still too small. Part 3:
8. The normal rat’s BMR increased from the TSH injections. 9. The thyroidectomized rat’s BMR increased by a little but the BMR of the normal rat was still bigger and so the dose was too small. 10. The hypophysectomized rat’s BMR increased from the TSH, but yet again, the normal rat’s BMR was still more, so the TSH dose was again too small. Part 4:
11. The normal rat’s BMR decreased from the PTU injections and it developed the palpable goiter because of build up of the precursors to thyroxine. 12. The thyroidectomized rat’s BMR was not effected by PTU injections. In this case, the BMR is still higher than the normal rat’s BMR because of the fact that the thyroidectomized rat had no thyroid gland. 13. The hypophysectomized rat’s BMR was also not effected by the PTU, and the BMR in this case was also more than the normal rat’s BMR because of the fact that the...
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