Deck 45: Hormones and the Endocrine System

Question 1

Which of the following statements about hormones is incorrect?

A)They are produced by endocrine glands.
B)They are modified amino acids, peptides, or steroid molecules.
C)They are carried by the circulatory system.
D)They are used to communicate between different organisms.
E)They elicit specific biological responses from target cells.

Answer 1

D

Question 2

The secretion of hormone A causes a change in the amount of protein X in an organism. If this mechanism works by positive feedback, which of the following statements represents that fact?

A)An increase in A produces an increase in X.
B)An increase in X produces a decrease in A.
C)A decrease in A produces an increase in X.
D)A and B are correct.
E)B and C are correct.

Answer 2

A

Question 3

Which of the following is (are)True?

A)Hormones regulate cellular functions, and generally negative feedback regulates hormone levels.
B)The circulating level of a hormone is held constant through a series of positive feedback loops.
C)Both lipid-soluble hormones and water-soluble hormones bind to intracellular protein receptors.
D)The ducts of endocrine organs release their contents into the bloodstream.
E)Only A and C are True.

Answer 3

A

Question 4

What do nitric oxide and epinephrine have in common?

A)They both function as neurotransmitters.
B)They both function as hormones.
C)They are both involved in the "fight-or-flight" response.
D)They bind the same receptors.
E)Only A and B are correct.

Question 5

Which of the following does not represent a chemical signal?

A)movement of a signal from one end of a nerve to the other end of the nerve
B)movement of a signal from one nerve to the next
C)an immune cell releasing a cytokine
D)a chemical released that affects the cell that releases it
E)chemicals released into the bloodstream from nerve cells

Question 6

Substance X is secreted by one cell, travels a short distance through interstitial fluid, and produces an effect in a cell immediately adjacent to the original secreting cell. All of the following terms could describe this substance except

A)nitric oxide.
B)neurotransmitter.
C)prostaglandin.
D)pheromone.
E)growth factor.

Question 7

Which of the following statements about hormones is correct?

A)Steroid and peptide hormones produce different effects but use the same biochemical mechanisms.
B)Steroid and peptide hormones produce the same effects but differ in the mechanisms that produce the effects.
C)Steroid hormones affect the synthesis of proteins, whereas peptide hormones affect the activity of proteins already present in the cell.
D)Steroid hormones affect the activity of certain proteins within the cell, whereas peptide hormones directly affect the processing of mRNA.
E)Steroid hormones affect the synthesis of proteins to be exported from the cell, whereas peptide hormones affect the synthesis of proteins that remain in the cell.

Question 8

Only certain cells in the body are target cells for the steroid hormone aldosterone. Which of the following is the best explanation for why these are the only cells that respond to this hormone?

A)Only target cells are exposed to aldosterone.
B)Only target cells contain receptors for aldosterone.
C)Aldosterone is unable to enter nontarget cells.
D)Nontarget cells destroy aldosterone before it can produce its effect.
E)Nontarget cells convert aldosterone to a hormone to which they do respond.

Question 9

What is the mode of action of aspirin and ibuprofen?

A)They inhibit the synthesis of prostaglandins.
B)They inhibit the release of nitric oxide, a potent vasodilator.
C)They block paracrine signaling pathways.
D)They stimulate the release of oxytocin.
E)They stimulate the release of endorphins.

Question 10

Why is it that some body cells respond differently to the same peptide hormones?

A)Different target cells have different genes.
B)Each cell knows how it fits into the body's master plan.
C)A target cell's response is determined by the product of a signal transduction pathway.
D)The circulatory system regulates responses to hormones by routing the hormones to specific targets.
E)The hormone is chemically altered in different ways as it travels through the circulatory system.

Question 11

A cell that contains proteins enabling a hormone to selectively bind to its plasma membrane is called a(n)

A)secretory cell.
B)plasma cell.
C)endocrine cell.
D)target cell.
E)regulatory cell.

Question 12

Which of the following statements about hormones is incorrect?

A)They are secreted into the extracellular fluid.
B)They circulate in blood or hemolymph.
C)They communicate messages throughout the body.
D)They travel through a dedicated pathway.
E)Not all cells respond to a particular hormone.

Question 13

Hormone X produces its effect in its target cells via the cAMP second messenger system. Which of the following will produce the greatest effect in the cell?

A)a molecule of hormone X applied to the extracellular fluid surrounding the cell
B)a molecule of hormone X injected into the cytoplasm of the cell
C)a molecule of cAMP applied to the extracellular fluid surrounding the cell
D)a molecule of cAMP injected into the cytoplasm of the cell
E)a molecule of activated, cAMP-dependent protein kinase injected into the cytoplasm of the cell

Question 14

Which of the following statements about hormones is incorrect?

A)Glands that produce them are ductless glands.
B)They are produced only by organs called endocrine organs.
C)Some are water soluble and some are not.
D)They often maintain steady-state conditions.
E)They may turn genes off or on.

Question 15

Which of the following are not part of homeostasis promotion or maintenance?

A)A stimulus causes an endocrine cell to secrete a particular hormone, which decreases the stimulus.
B)A hormone acts in an antagonistic way with another hormone.
C)A hormone is involved in a positive feedback loop.
D)Signal transduction brings about a response in the target cell.
E)Secretin promotes an increase in the pH of the duodenum.

Question 16

Which of the following statements about hormones that promote homeostasis is incorrect?

A)A stimulus causes an endocrine cell to secrete a particular hormone.
B)The hormone travels in the bloodstream to target cells.
C)Specific receptors bind with the hormone.
D)Signal transduction brings about a response in the target cell.
E)This response feeds back to promote the release of more hormone.

Question 17

Which of the following is a local regulator responsible for activating an enzyme that relaxes smooth muscle cells?

A)nitric oxide
B)prostaglandin F
C)epinephrine
D)A and B only
E)A, B, and C

Question 18

Which of the following examples is incorrectly paired with its class?

A)cytokines-local regulator
B)estrogen-steroid hormone
C)prostaglandin-peptide hormone
D)ecdysone-steroid hormone
E)neurotransmitter-local regulator

Question 19

When an individual is subject to short-term starvation, most available food is used to provide energy (metabolism)rather than building blocks (growth and repair). Which hormone would be particularly active in times of food shortage?

A)epinephrine
B)glucagon
C)oxytocin
D)antidiuretic hormone
E)insulin

Question 20

Prostaglandins are local regulators whose basic structure is derived from

A)oligosaccharides.
B)fatty acids.
C)steroids.
D)amino acids.
E)nitric oxide

Question 21

The endocrine system and the nervous system are structurally related. Which of the following cells best illustrates this relationship?

A)a neuron in the spinal cord
B)a steroid-producing cell in the adrenal cortex
C)a neurosecretory cell in the hypothalamus
D)a brain cell in the cerebral cortex
E)a cell in the pancreas that produces digestive enzymes

Question 22

Which of the following statements about the hypothalamus is incorrect?

A)It functions as an endocrine gland.
B)It is part of the central nervous system.
C)It is subject to feedback inhibition by certain hormones.
D)It secretes tropic hormones that act directly on the gonads.
E)Its neurosecretory cells terminate in the posterior pituitary.

Question 23

Oxytocin and ADH are produced by the __________ and stored in the __________.

A)hypothalamus; neurohypophysis
B)adenohypophysis; kidneys
C)anterior pituitary; thyroid
D)adrenal cortex; adrenal medulla
E)posterior pituitary; anterior pituitary

Question 24

Which of the following have nontropic effects only?

A)FSH
B)LH
C)TSH
D)MSH
E)ACTH

Question 25

Prolactin stimulates mammary gland growth and development in mammals and regulates salt and water balance in freshwater fish. Many scientists think that this wide range of functions indicates which of the following?

A)Prolactin is a nonspecific hormone.
B)Prolactin has a unique mechanism for eliciting its effects.
C)Prolactin is an evolutionary conserved hormone.
D)Prolactin is derived from two separate sources.
E)Prolactin interacts with many different receptor molecules.

Question 26

Which of the following endocrine disorders is not correctly matched with the malfunctioning gland?

A)diabetes and pancreas
B)giantism and pituitary
C)goiter and adrenal medulla
D)tetany and parathyroid
E)dwarfism and pituitary

Question 27

Which hormone exerts antagonistic action to PTH (parathyroid hormone)?

A)thyroxine
B)epinephrine
C)growth hormone
D)calcitonin
E)glucagon

Question 28

Which combination of hormones helps a mother to produce milk and nurse her baby?

A)prolactin and calcitonin
B)oxytocin and prolactin
C)follicle-stimulating hormone and luteinizing hormone
D)luteinizing hormone and oxytocin
E)oxytocin, prolactin, and luteinizing hormone

Question 29

The hypothalamus controls the anterior pituitary by means of

A)releasing hormones.
B)second messengers.
C)third messengers.
D)antibodies.
E)cytokines.

Question 30

Synthetic versions of which of the following hormones are being used as insecticides to prevent insects from maturing into reproducing adults?

A)ecdysone
B)juvenile hormone
C)oxytocin
D)brain hormone
E)prothoracic hormone

Question 31

If a person drinks a large amount of water in a short period of time, he or she may die from water toxicity. ADH can help prevent water retention through interaction with target cells in the

A)anterior pituitary.
B)posterior pituitary.
C)adrenal gland.
D)bladder.
E)kidney.

Question 32

Iodine is added to commercially-prepared table salt to help prevent deficiencies of this essential mineral. Which gland(s)require(s)iodine to function properly?

A)parathyroids
B)adrenal
C)thyroid
D)pancreas
E)ovaries and testes

Question 33

One reason a person might be severely overweight is due to

A)an undersecretion of thyroxine.
B)a defect in hormone release from the posterior pituitary.
C)a lower than normal level of insulin-like growth factors.
D)hyposecretion of oxytocin.
E)a higher than normal level of melatonin.

Question 34

Which of the following is an endocrine gland?

A)parathyroid gland
B)salivary gland
C)sweat gland
D)sebaceous gland
E)gallbladder

Question 35

Which of the following glands shows both endocrine and exocrine activity?

A)pituitary
B)parathyroid
C)salivary
D)pancreas
E)adrenal

Question 36

Which of the following statements about endocrine glands is incorrect?

A)The parathyroids regulate metabolic rate.
B)The thyroid participates in blood calcium regulation.
C)The pituitary participates in the regulation of the gonads.
D)The adrenal medulla produces "fight-or-flight" responses.
E)The pancreas helps to regulate blood sugar concentration.

Question 37

Based on their effects, which pair below could be considered antagonistic?

A)prostaglandin F and nitric oxide
B)growth hormone and ecdysone
C)endocrine and exocrine glands
D)hormones and target cells
E)neurosecretory cells and neurotransmitters

Question 38

The star of a recent movie was a caterpillar that never matured into an adult. It simply got larger with each molt. What is the probable reason why the caterpillar did not mature into an adult?

A)lack of ecdysone
B)lack of juvenile hormone
C)decreased level of ecdysone
D)increased level of juvenile hormone
E)lack of the melatonin hormone

Question 39

Short blood vessels connect two capillary beds lying in which of the following?

A)hypothalamus and thalamus
B)anterior pituitary and posterior pituitary
C)hypothalamus and anterior pituitary
D)posterior pituitary and thyroid gland
E)anterior pituitary and adrenal gland

Question 40

Tropic hormones from the anterior pituitary directly affect the release of which of the following?

A)parathyroid hormone
B)calcitonin
C)epinephrine
D)thyroxine
E)glucagon

Question 41

All of the following are steroid hormones except

A)androgen.
B)cortisol.
C)estrogen.
D)insulin.
E)testosterone.

Question 42

What happens when beta cells of the pancreas release insulin into the blood?

A)Blood glucose levels rise to a set point and stimulate glucagon release.
B)Body cells take up more glucose.
C)The liver breaks down glycogen to glucose.
D)Alpha cells are stimulated to release glucose into the blood.
E)Both B and D are correct.

Question 43

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Which of the following stimulates the contraction of uterine muscle?

A)ecdysone
B)glucagon
C)thyroxine
D)oxytocin
E)growth hormone

Question 44

Which of the following glands is controlled directly by the hypothalamus or central nervous system but not the anterior pituitary?

A)ovary
B)adrenal medulla
C)adrenal cortex
D)testis
E)thyroid

Question 45

If the adrenal cortex were removed, which group of hormones would be most affected?

A)steroid
B)peptide
C)tropic
D)amino acid-derived
E)paracrine

Question 46

Which of the following endocrine structures are derived from nervous tissue?

A)thymus and thyroid glands
B)ovaries and the testes
C)liver and the pancreas
D)anterior pituitary and the adrenal cortex
E)posterior pituitary and the adrenal medulla

Question 47

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Which of the following is secreted by the anterior pituitary?

A)ecdysone
B)glucagon
C)thyroxine
D)oxytocin
E)growth hormone

Question 48

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-The results most likely occurred because progesterone exerts an effect on the

A)general health of the rat.
B)size of the fetus.
C)maintenance of the uterus.
D)gestation period of rats.
E)number of eggs fertilized.

Question 49

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Melatonin has been found to participate in all of the following except

A)skin pigmentation.
B)monitoring day length.
C)reproduction.
D)biological rhythms.
E)calcium deposition in bone.

Question 50

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Which of the following endocrine structures is (are)not controlled by a tropic hormone from the anterior pituitary?

A)pancreatic islet cells
B)thyroid gland
C)adrenal cortex
D)ovaries
E)testes

Question 51

Which of the following statements about the adrenal gland is correct?

A)During stress, TSH stimulates the adrenal cortex and medulla to secrete acetylcholine.
B)During stress, the alpha cells of islets secrete insulin and simultaneously the beta cells of the islets secrete glucagon.
C)During stress, ACTH stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla.
D)At all times, the anterior portion secretes ACTH, while the posterior portion secretes oxytocin.
E)At all times, the adrenal gland monitors calcium levels in the blood and regulates calcium by secreting the two antagonistic hormones, epinephrine and norepinephrine.

Question 52

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Which of the following is secreted by the pancreas?

A)ecdysone
B)glucagon
C)thyroxine
D)oxytocin
E)growth hormone

Question 53

The endocrine system and the nervous system are chemically related. Which of the following substances best illustrates this relationship?

A)estrogen
B)calcitonin
C)norepinephrine
D)calcium
E)ecdysone

Question 54

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Which of the following stimulates and maintains metabolic processes?

A)ecdysone
B)glucagon
C)thyroxine
D)oxytocin
E)growth hormone

Question 55

Blood samples taken from an individual who had been fasting for 24 hours would have which of the following?

A)high levels of insulin
B)high levels of glucagon
C)low levels of insulin
D)low levels of glucagon
E)both B and C

Question 56

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Testosterone is an example of

A)an androgen.
B)an estrogen.
C)a progestin.
D)a catecholamine.
E)melatonin.

Question 57

Which of the following are synthesized from the amino acid tyrosine?

A)epinephrine
B)catecholamines
C)thyroxin
D)A and B only
E)A, B, and C

Question 58

Which of the following hormones is (are)secreted by the adrenal gland in response to stress and promote(s)the synthesis of glucose from noncarbohydrate substrates?

A)glucagon
B)glucocorticoids
C)epinephrine
D)thyroxine
E)ACTH

Question 59

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Which combination of gland and hormone would be linked to winter hibernation and spring reproduction in bears?

A)pineal gland, melatonin
B)hypothalamus gland, melatonin
C)anterior pituitary gland, gonadotropin-releasing hormone
D)pineal gland, estrogen
E)posterior pituitary gland, thyroid-stimulating hormone

Question 60

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Which of the following is a steroid hormone that triggers molting in arthropods?

A)ecdysone
B)glucagon
C)thyroxine
D)oxytocin
E)growth hormone

Question 61

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Estradiol is an example of

A)an androgen.
B)an estrogen.
C)a progestin.
D)a catecholamine.
E)melatonin.

Question 62

An example of antagonistic hormones controlling homeostasis is

A)thyroxine and parathyroid hormone in calcium balance.
B)insulin and glucagon in glucose metabolism.
C)progestins and estrogens in sexual differentiation.
D)epinephrine and norepinephrine in fight-or-flight responses.
E)oxytocin and prolactin in milk production.

Question 63

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Which of the following is secreted by the pineal gland?

A)androgens
B)estrogens
C)progestins
D)catecholamines
E)melatonin

Question 64

Which of the following is the most likely explanation for hypothyroidism in a patient whose iodine level is normal?

A)a disproportionate production of T3 to T4
B)hyposecretion of TSH
C)hypersecretion of TSH
D)hypersecretion of MSH
E)a decrease in the thyroid secretion of calcitonin

Question 65

Which of the following is not an accurate statement?

A)Hormones are chemical messengers that travel to target cells through the circulatory system.
B)Hormones often regulate homeostasis through antagonistic functions.
C)Hormones of the same chemical class usually have the same function.
D)Hormones are secreted by specialized cells usually located in endocrine glands.
E)Hormones are often regulated through feedback loops.

Question 66

Which of the following hormones is incorrectly paired with its action?

A)oxytocin-stimulates uterine contractions during childbirth
B)thyroxine-stimulates metabolic processes
C)insulin-stimulates glycogen breakdown in the liver
D)ACTH-stimulates the release of glucocorticoids by the adrenal cortex
E)melatonin-affects biological rhythms, seasonal reproduction

Question 67

Growth factors are local regulators that

A)are produced by the anterior pituitary.
B)are modified fatty acids that stimulate bone and cartilage growth.
C)are found on the surface of cancer cells and stimulate abnormal cell division.
D)are proteins that bind to cell-surface receptors and stimulate growth and development of target cells.
E)convey messages between nerve cells.

Question 68

The relationship between the insect hormones ecdysone and PTTH

A)is an example of the interaction between the endocrine and nervous systems.
B)illustrates homeostasis achieved by positive feedback.
C)demonstrates that peptide-derived hormones have more widespread effects than steroid hormones.
D)illustrates homeostasis maintained by antagonistic hormones.
E)demonstrates competitive inhibition for the hormone receptor.

Question 69

A distinctive feature of the mechanism of action of thyroid hormones and steroid hormones is that

A)these hormones are regulated by feedback loops.
B)target cells react more rapidly to these hormones than to local regulators.
C)these hormones bind with specific receptor proteins on the plasma membrane of target cells.
D)these hormones bind to receptors inside cells.
E)these hormones affect metabolism.

Question 70

The main target organs for tropic hormones are

A)muscles.
B)blood vessels.
C)endocrine glands.
D)kidneys.
E)nerves.

Question 71

The question below refers to the following information.
In an experiment, rats' ovaries were removed immediately after impregnation and then the rats were divided into two groups. Treatments and results are summarized in the table below
$\begin{array}{lcc}\hline&\text { Group } 1 &\text { Group } 2\\\hline (\text { Daily injections of }&&\\\text { progesterone (milligrams) } & 0.25 & 2.0 \\\text { Percentage of rats that } & & \\\text { carried fetuses to birth } & 0 & 100\\\hline\end{array}$

Figure 45.1

-Epinephrine is an example of

A)an androgen.
B)an estrogen.
C)a progestin.
D)a catecholamine.
E)melatonin.