Researchers measured prolactin and growth hormone in the blood plasma of six subjects at regular intervals over a 24-hour period. The investigators were interested in determining if the levels of these two hormones cycle over a 24-hour period. The Figure presents the results of their experiments, with the y axis values showing the amount of each hormone expressed as a percentage of the 24-hour mean value, and each point showing the average of the six subjects’ levels.
FIGURE Mean concentrations of prolactin and growth hormone in plasma, averaged for six subjects and expressed as a percentage of the average concentrations measured for the 24-hour period.
Do the results support the hypothesis that the changes in prolactin level over a 24-hour period are associated with the sleep–wake cycle?
Source: From J. F. Sassin et al. 1972. Human prolactin: 24-hour pattern with increased release during sleep. Science 177:1205–1207.
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Chapter 42 Solutions
Biology: The Dynamic Science (MindTap Course List)
- Levels of the Female Reproductive Hormones during the Menstrual Cycle Hormone Day 4 Day 14 Day 21 Estrogen (pg/mL) N/A >100 <60 Progesterone (ng/mL) N/A <1.5 >15 LH (mIU/mL) <7 >15 N/A FSH (mIU/mL) <13 >15 N/A Identify the hormones numbered in the graph above. Number: Answer Answer Answer Answer Hormone: Estrogen Progesterone LH FSHarrow_forwardOne of the main endocrine glands in the human body is the pituitary gland. This gland produces a variety of hormones with different effects. Among these are a heterogeneous group of hormones called tropic hormones, which directly stimulate the secretion of other hormones from downstream endocrine glands. Which of the following are tropic hormones? Select all that apply. LH Prolactin Oxytocin ACTH TSH testosteronearrow_forwardYou receive a prescription for thyroid 11mg capsules with directions of 1 capsule daily for 54 days. You have a 10g container of thyroid powder and lactose powder available as a diluent. Your scale is calibrated with a sensitivity requirement of 1mg. Please calculate in milligrams the least amount of lactose needed to accurately (+5%) weigh out the final mixture. Answer: The correct answer is: 486 You receive a prescription for progesterone 109mg capsules with directions of 1 capsule daily for 30 days. You have a 10g container of progesterone powder and lactose powder available as a diluent. Your scale is calibrated with a sensitivity requirement of 10mg. Please calculate in milligrams the least amount of lactose needed to accurately (+5%) weigh out the final mixture. Answer: The correct answer is: 2730 If an ophthalmic solution contains 2 mg of dexamethasone phosphate in each milliliter of solution, how many milligrams of dexamethasone phosphate would be contained in 13 drops if the…arrow_forward
- Place the following steps (showing how a steroid hormone changes the activities of its target cells) in order of what happens first, second, third, fourth, and last. Refer to image. The hormone-receptor complex enters the nucleus of the cell and binds to the DNA. The steroid hormone passes through the cell membrane. The hormone attaches to a receptor in the cytoplasm, forming a hormone-receptor complex. A gene in the DNA is activated, and transcription and translation take place. Proteins that alter the cell′s activities, such as enzymes, are made. 2. Place the following steps (showing how a hydrophilic hormone changes the activities of its target cells) in order of what happens first, second, third, and last. Refer to image. The activity of the target cell is changed by the final enzyme in the cascade. The second messenger activates or deactivates certain enzymes in a cascade fashion. A second messenger is activated. Hormone binds to a receptor protein.arrow_forwardWhich of the following would be better handled with an endocrine system response (not a nervous system response) and why: A. Assessing a noise in your environment (such as the hum of an air conditioner), and adapting to it (so you no longer unnecessarily pay attention to something unimportant). B. Stimulating the gradual development (it takes days!) of follicles in the ovary, because hormonal signals have a more extended duration than a nervous system signal. C. Both choice A and choice B D. Neither A nor B.arrow_forwardWhich of the following labeled cells in the photomicrograph shown synthesizes antimullerian hormone? A B C D Earrow_forward
- Consider the communication between the hypothalamus, pituitary and various target organs when answering this question. For each condition discussed, state the change you would expect to find for each hormone/compound addressed - INCREASED, DECREASED, UNAFFECTED, CAN'T INTERPRET: A patient suffering from untreated Graves disease: A) TSH B) Calcitonin C) Thyroxine(T4/T3) D) TRH A patient suffering from untreated goiter: A) TSH B) Calcitonin C) Thyroxine(T4/T3) D) TRH A patient suffering from pituitary tumor secreting ACTH: A) CRH B) ACTH C) Cortisol D) Plasma potassium level Now, let's consider calcium metabolism and balance. For each condition discussed, state the change you would expect to find for hormone/calcium levels - INCREASED, DECREASED, UNAFFECTED, CAN'T INTERPRET: A patient with…arrow_forwardWhat is the expected effect on reproduction on an individual with hormone levels shown in this graph. Identify two physiological changes that will not occur due to the atypical hormone levels shown above.arrow_forwardWhich two of the following statements are correct? 1. for all cortisol assays, the corticosteroid-binding protein is also being measured 2. salivary cortisol represents 'free' 'active' cortisol 3. urinary cortisol contains bound and free cortisol 4. protein bound cortisol cannot enter cells 5. salivary cortisol contains bound and free cortisolarrow_forward
- Explain the following mechanisms of action of peptide and steroid hormones in its target cells. i. Cyclic adenosine monophosphate (cAMP) mechanism. ii. Phosphatidylinositol biphosphate-calcium (PIP-Ca) mechanism. iii. Direct gene activation mechanismarrow_forwardIn a hypothetical cAMP-mediated signal transduction cascade, the GTP-αs/adenylate cyclase interaction following a single hormone–receptor binding event lasts for 2.3 seconds. The catalytic rate (turnover number) for the adenylate cyclase in question is 350 cAMP molecules produced per second. How many cAMP molecules would be produced if five hormone-receptor binding events were to occur before the hormone molecule dissipates in the bloodstream? What is the amplification effect of this step in the signaling pathway?arrow_forwardDoes the following table properly summarize negative feedback loop of each tropic hormone? If not, place the correct answer beside each box.arrow_forward
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