Metabolism and Thyroid Hormone

Activity 1: Metabolism and Thyroid Hormone Name: Date: Session ID: Pre-lab Quiz Results You scored 100% by answering 6 out of 6 questions correctly. 1 Which of the following statements about metabolism is false? You correctly answered: All of the energy from metabolism is ultimately stored in the chemical bonds of ATP. 2 Thyroxine is You correctly answered: the most important hormone for maintaining the metabolic rate and body temperature. 3 Thyroid-stimulating hormone (TSH) is You correctly answered: produced in the pituitary gland. 4 An injection of TSH to an otherwise normal animal will cause which of the following? You correctly answered: goiter development. 5 Thyrotropin-releasing hormone (TRH) is You correctly answered: secreted by the hypothalamus. 6 Which of the following statements is true? You correctly answered: The hypothalamus primarily secretes tropic hormones that stimulate the secretion of other hormones. Experiment Results Predict Questions 1 Predict Question 1: Make a prediction about the basal metabolic rate (BMR) of the remaining rats compared with the BMR of the normal rat you just measured. Your answer: The BMR of both remaining rats will be lower than the normal rat's BMR. 2 Predict Question 2: What do you think will happen after you inject thyroxine into the three rats? Your answer: The normal rat will become hyperthyroidic but will not develop a goiter. 3 Predict Question 3: What do you think will happen after you inject TSH into the three rats? Your answer: The normal rat will become hyperthyroidic and develop a goiter. 4 Predict Question 4: Propylthiouracil (PTU) is a drug that inhibits the production of thyroxine by blocking the attachment of iodine to tyrosine residues in the follicle cells of the thyroid gland (iodinated tyrosines are linked together to form thyroxine). What do you think will happen after you inject PTU into the three rats? Your answer: The normal rat will become hyperthyroidic and develop a goiter. Stop & Think Questions 1 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 426 ml O2/hr. 2 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1704 ml O2/kg/hr. 3 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 378 ml O2/hr. 4 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1536.59 ml O2/kg/hr. 5 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 372 ml O2/hr. 6 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1518.37 ml O2/kg/hr. 7 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800). The normal rat is You correctly answered: euthyroid. 8 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800). The thyroidectomized (Tx) rat is You correctly answered: hypothyroid. 9 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800). The hypophysectomized (Hypox) rat is You correctly answered: hypothyroid. 10 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 498 ml O2/hr. 11 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1992 ml O2/kg/hr. 12 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 474 ml O2/hr. 13 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1926.83 ml O2/kg/hr. 14 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 468 ml O2/hr. 15 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1910.20 ml O2/kg/hr. 16 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the thyroxine injection. The normal rat is You correctly answered: hyperthyroid. 17 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the thyroxine injection. The thyroidectomized (Tx) rat is You correctly answered: hyperthyroid. 18 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the thyroxine injection. The hypophysectomized (Hypox) rat is You correctly answered: hyperthyroid. 19 Which of the rats developed a goiter after injection with thyroxine? You correctly answered: None of the rats developed a goiter with this injection. 20 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 480 ml O2/hr. 21 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1920 ml O2/kg/hr. 22 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 372 ml O2/hr. 23 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1512.19512 ml O2/kg/hr. 24 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 468 ml O2/hr. 25 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1910.20 ml O2/kg/hr. 26 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the TSH injection. The normal rat is You correctly answered: hyperthyroid. 27 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the TSH injection. The thyroidectomized (Tx) rat is You correctly answered: hypothyroid. 28 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the TSH injection. The hypophysectomized (Hypox) rat is You correctly answered: hyperthyroid. 29 Which of the rats did not develop a goiter after injection with TSH? You correctly answered: the thyroidectomized rat. 30 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 378 ml O2/hr. 31 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1512 ml O2/kg/hr. 32 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 372 ml O2/hr. 33 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1512.19512 ml O2/kg/hr. 34 Calculate the oxygen consumption per hour for this rat using the following equation. ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour Enter the oxygen consumption per hour. You answered: 378 ml O2/hr. 35 Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms to use this equation). Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr Enter the metabolic rate. You answered: 1542.85 ml O2/kg/hr. 36 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the PTU injection. The normal rat is You correctly answered: hypothyroid. 37 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the PTU injection. The thyroidectomized (Tx) rat is You correctly answered: hypothyroid. 38 Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthyroid (high thyroid levels; BMR above 1800) after the PTU injection. The hypophysectomized (Hypox) rat is You correctly answered: hypothyroid. 39 Which of the rats developed a goiter after injection with PTU? You correctly answered: the normal rat. Experiment Data Rat Weight (g) ml O2/min ml O2/hr BMR (ml O 2/kg/hr) Palpation Injected Normal 250 7.1 426.00 1704.00 No Mass none Tx 246 6.3 378.00 1536.59 No Mass none Hypox 245 6.2 372.00 1518.37 No Mass none Normal 250 8.3 498.00 1992.00 No Mass thyroxine Tx 246 7.9 474.00 1926.83 No Mass thyroxine Hypox 245 7.8 468.00 1910.20 No Mass thyroxine Normal 250 8.0 480.00 1920.00 Mass TSH Tx 246 6.2 372.00 1512.20 No Mass TSH Hypox 245 7.8 468.00 1910.20 Mass TSH Normal 250 6.3 378.00 1512.00 Mass PTU Tx 246 6.2 372.00 1512.20 No Mass PTU Hypox 245 6.3 378.00 1542.86 No Mass PTU Post-lab Quiz Results You scored 100% by answering 7 out of 7 questions correctly. 1 How would you treat a thyroidectomized animal so that it functions like a "normal" animal? You correctly answered: Provide the animal T4 supplements. 2 As a result of the missing hormone(s) in the hypophysectomized rat, what would be an expected symptom? You correctly answered: decreased basal metabolic rate. 3 An injection of thyroxine to an otherwise normal rat will cause which of the following? You correctly answered: hyperthyroidism. 4 Why didn't any of the rats develop a goiter after thyroxine injection? You correctly answered: In all cases, TSH levels were not elevated by the thyroxine injection. 5 Why did the normal rat develop a palpable goiter with the TSH injection? You correctly answered: The TSH receptors on the thyroid gland were excessively stimulated. 6 An injection of propylthiouracil to an otherwise normal animal will cause which of the following? You correctly answered: goiter development. 7 Why did the normal rat develop a palpable goiter with the propylthiouracil injection? You correctly answered: The injection decreased the negative feedback mechanism on TSH. Review Sheet Results 1 Part 1: Determining the Basal Metabolic Rates Which rat had the fastest basal metabolic rate (BMR)? Your answer: The normal rat that was injected with thyroxine had the fastest basal metabolic rate because it is not missing its pituitary gland or thyroid gland. 2 Why did the metabolic rates differ between the normal rat and the surgically altered rats? How well did the results compare with your prediction? Your answer: The metabolic rates differed between the normal rat and the surgically altered rats in the fact that the normal rat had a higher BMR than the others. This is due to the fact that the normal rat has the pituitary and thyroid glands to stimulate as well as regulate the release of the thyroid hormones. In the surgically altered rats, one was missing the pituitary gland while the other was missingthe thyroid gland making the production of thyroxine low resulting in a lower BMR. My prediction matched and was correct with the results. 3 If an animal has been thyroidectomized, what hormone(s) would be missing in its blood? Your answer: If an animal has been thyroidectomized that means they would have no thyroid gland meaning there would be no thyroxineT3 T4 in its blood because the thyroid gland secretes thyroxine. 4 If an animal has been hypophysectomized, what effect would you expect to observe in the hormone levels in its body? Your answer: If an anima has been hypophysectomized that means their pituitary gland has been removed resulting in TSH (thyroid stimulating hormone) to be missing and thyroxine to not be produced. This would cause the metabolic rate and body temperature to decrease. 5 Part 2: Determining the Effect of Thyroxine on Metabolic Rate What was the effect of thyroxine injections on the normal rat's BMR? Your answer: The effect of thyroxine injections on the normal rat's BMR caused it to rise causing the rat to become hyperthyroidic. However, it did not develop a goiter. 6 What was the effect of thyroxine injections on the thyroidectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Was the dose of thyroxine in the syringe too large, too small, or just right? Your answer: The effect of thyroxine injections on the thyroidectomized rat's BMR was that it caused it to increase making the rat become hyperthyroidic with no goiter development. The BMR in this case compared to the normal rat's BMR is that they were both hyperthyroidic but even though they were both hyperthyroidic, the normal rat's BMR was still higher. The dose of thyroxine in the syringe was too high because it caused the rat with no thyroid gland (it won't produce thyroxine) to become hyperthyroidic meaning it had high thyroid levels. 7 What was the effect of thyroxine injections on the hypophysectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Was the dose of thyroxine in the syringe too large, too small, or just right? Your answer: The effect of thyroxine injections on the hypophysectomized rat's BMR was that it caused it to increase to the point of becoming hyperthyroidic. The BMR in this case compared with the normal rats BMR is that they both became hyperthyroidic but the normal rat still had a higher BMR than that of the hypophysectomized rat. The dose was too high because it made the hypophysectomized rat's BMR become hyperthyroidic meaningthe thyroid levels were too high and not within normal range. 8 Part 3: Determining the Effect of TSH on Metabolic Rate What was the effect of thyroid-stimulating hormone (TSH) injections on the normal rat's BMR? Your answer: The effect of the thyroid-stimulating hormone (TSH) injections on the normal rat's BMR was that it caused it to increase becoming hyperthyroidic and developed a goiter. 9 What was the effect of TSH injections on the thyroidectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Why was this effect observed? Your answer: The effect of TSH injections on the thyroidectomized rat's BMR was that it caused it to decrease causing the rat's BMR to become hypothyroidic (low thyroid levels). The BMR in this case compared with the normal rat's BMR is that the normal rats BMR is way higher (hyperthyroidic) than the thyroidectomized rat's BMR (hypothyroidic). This effect was observed because without a thyroid gland to stimulate, the TSH becomes lower and less effective than the normal rat who has a thyroid to stimulate. 10 What was the effect of TSH injections on the hypophysectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Was the dose of TSH in the syringe too large, too small, or just right? Your answer: The effect of TSH injections on the hypophysectomized rat's BMR is that it caused it to increase making it be hyperthyroidic. The BMR in this case compared with the normal rat's BMR is that they are both hyperthyroidic but the normal rat's BMR is still higher. The dose of the TSH in the syringe was too high because it caused the hypophysectomized rat to develop a goiter. 11 Part 4: Determining the Effect of Propylthiouracil on Metabolic Rate What was the effect of propylthiouracil (PTU) injections on the normal rat's BMR? Why did this rat develop a palpable goiter? Your answer: The effect of propylthiouracil (PTU) injections on the normal rat's BMR was that it caused it to decrease making it become hypothyroidic (low thyroid levels). This rat developed a palpable goiter because propylthiouracil (PTU) inhibits production of thyroxine and decreased the negative feedback mechanism of TSH. 12 What was the effect of PTU injections on the thyroidectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Why was this effect observed? Your answer: The effect of PTU injections on the thyroidectemized rat's BMR is that it caused it to decrease making it become hypothyroidic but there was not much of a change since it does not have a thyroid gland to be affected. The BMR in this case compared with the normal rat's BMR was that they were both hypothyroidic.This effect is observed because the thyroidectemized rat does not have a thyroid to produce thyroxine and PTU inhibits production of thyroxine. 13 What was the effect of PTU injections on the hypophysectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Why was this effect observed? Your answer: The effect of PTU injections on the hypophysectomized rat's BMR was that it caused it to slightly increase but it was still considered to be hypothroidic. However, because the rat has no pituitary gland to secrete the hormone TSH to target the thyroid gland there was not much visible change to be observed. Compared to the normal rat's BMR, the hypophysectomized rat's BMR was higher. This effect was observed because the hypophysectomized rat does not have a pituitary gland to regulate thyroxine or TSH to stabilize metabolism and heat.