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NU 545 Unit 3 Questions with Detailed
Verified Answers
Question: know which hormones are water-soluble and which are lipid-
soluble
Ans: water soluble:
peptides- GH, insulin, leptin, PTH, prolactin
glycoproteins- FSH, LH, TSH
polypeptides: adrenocorticotropic hormone, ADH, calcitonin, endorphins,
glucagon, hypothalamic hormones, lipotropins, melanocyte-stimulating
hormone, oxytocin, somatostatin, thymosin, thyrotropin-releasing
hormone
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amines: Epi, Norepi
lipid soluble:
Thyroxine: T3 and T4
steroids: Estrogen, glucocorticoids, mineralocorticoids, progestin,
testosterone (all steroids are cholesterol based)
derivatives of arachidonic acid (autocrine or paracrine action):
Leukotrienes, Prostacyclins, prostaglandins, thromboxanes
Question: How are water-soluble hormones transported?
Ans: Water-soluble hormones are proteins that are polarized with a high
molecular weight. Because they cannot diffuse across the lipid cell plasma
membrane, they must interact or bind with receptors in or on the cell
membrane to activate a second-messenger to mediate short-acting
responses.
Question: How are lipid-soluble hormones transported?
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Ans: Lipid-soluble hormones diffuse freely across the cell and nuclear
membrane and bind with cytosolic or nuclear receptors. (can also bind with
receptors in or on the plasma membrane)
Question: know how protein hormones are transported in the blood
Ans: peptide or protein hormones are water-soluble and circulate in free
(unbound) forms
Question: why do water soluble hormones have a short half-life?
Ans: because they are catabolized by circulating enzymes. Remember
they are unbound.
Question: How long can lipid-soluble hormones remain in the blood?
Ans: For hours to days. They last longer in the blood because they are
bound to carrier/transport proteins.
Question: only free hormones can do what?
Ans: initiate changes within a target cell
Question: How does the concentration of binding proteins affect the
concentration of free hormones in the plasma?
Ans: because equilibrium exists between the concentration of free
hormones and hormones bound to plasma proteins
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Question: What are the two main functions of the target cell hormone
receptor?
Ans: 1. To recognize and bind with high affinity to their particular
hormones
2. To initiate a signal to appropriate intracellular effectors
*when a hormone is released into the circulatory system, it is distributed
throughout the body, but only those cells with appropriate hormone
receptors for that hormone are affected.
Question: what is oxytocin?
Ans: a polypeptide hormone synthesized in the supraoptic and
paraventricular nuclei of the hypothalamus. Oxytocin is implicated in
behavior responses, especially in women. Oxytocin plays a role in brain
responsiveness to stressful stimuli, especially in the pregnant and
postpartum states.
Question: How does oxytocin relate to the pituitary gland?
NU 545 Unit 3 Questions with Detailed
Verified Answers
Question: know which hormones are water-soluble and which are lipid-
soluble
Ans: water soluble:
peptides- GH, insulin, leptin, PTH, prolactin
glycoproteins- FSH, LH, TSH
polypeptides: adrenocorticotropic hormone, ADH, calcitonin, endorphins,
glucagon, hypothalamic hormones, lipotropins, melanocyte-stimulating
hormone, oxytocin, somatostatin, thymosin, thyrotropin-releasing
hormone
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amines: Epi, Norepi
lipid soluble:
Thyroxine: T3 and T4
steroids: Estrogen, glucocorticoids, mineralocorticoids, progestin,
testosterone (all steroids are cholesterol based)
derivatives of arachidonic acid (autocrine or paracrine action):
Leukotrienes, Prostacyclins, prostaglandins, thromboxanes
Question: How are water-soluble hormones transported?
Ans: Water-soluble hormones are proteins that are polarized with a high
molecular weight. Because they cannot diffuse across the lipid cell plasma
membrane, they must interact or bind with receptors in or on the cell
membrane to activate a second-messenger to mediate short-acting
responses.
Question: How are lipid-soluble hormones transported?
, Page | 3
Ans: Lipid-soluble hormones diffuse freely across the cell and nuclear
membrane and bind with cytosolic or nuclear receptors. (can also bind with
receptors in or on the plasma membrane)
Question: know how protein hormones are transported in the blood
Ans: peptide or protein hormones are water-soluble and circulate in free
(unbound) forms
Question: why do water soluble hormones have a short half-life?
Ans: because they are catabolized by circulating enzymes. Remember
they are unbound.
Question: How long can lipid-soluble hormones remain in the blood?
Ans: For hours to days. They last longer in the blood because they are
bound to carrier/transport proteins.
Question: only free hormones can do what?
Ans: initiate changes within a target cell
Question: How does the concentration of binding proteins affect the
concentration of free hormones in the plasma?
Ans: because equilibrium exists between the concentration of free
hormones and hormones bound to plasma proteins
, Page | 4
Question: What are the two main functions of the target cell hormone
receptor?
Ans: 1. To recognize and bind with high affinity to their particular
hormones
2. To initiate a signal to appropriate intracellular effectors
*when a hormone is released into the circulatory system, it is distributed
throughout the body, but only those cells with appropriate hormone
receptors for that hormone are affected.
Question: what is oxytocin?
Ans: a polypeptide hormone synthesized in the supraoptic and
paraventricular nuclei of the hypothalamus. Oxytocin is implicated in
behavior responses, especially in women. Oxytocin plays a role in brain
responsiveness to stressful stimuli, especially in the pregnant and
postpartum states.
Question: How does oxytocin relate to the pituitary gland?
