Name______________________________
General Instructions: There are 100 points on this exam; 85 on
objective and 15 on essays. The exam has 6 pages. Budget your time and
good luck.
1. (42 points) Select three hormones from the list below that differ
in the classes of mechanisms of action on target cells that they utilize.
Describe each of these hormones with respect to: a) chemical class of hormone,
b) anatomical site of production (be as precise as possible), c) anatomical
site of action, d) type and cellular location of receptor utilized, e)
mechanism of action (indicate the key transducer(s) and/or effector(s)
involved), f) physiological role within the body, and g) usual endogenous
method of control or regulation of production of the hormone.
Somatostatin GHRH CRH Luteinizing hormone Testosterone FSH Vasopressin
Cortisol Thyroxine MSH Thyroid Releasing Hormone IGF-I Somatotropin Oxytocin
Prolactin Thyrotropin Corticotropin Glucagon
Hormone 1: Name (of hormone) ________________________________________________
a) chemical class:
b) anatomical site of production:
c) anatomical site of action:
d) type and location of receptor:
e) mechanism of action:
f) physiological role:
g) control of production:
Hormone 2: Name (of hormone) ________________________________________________
a) chemical class:
b) anatomical site of production:
c) anatomical site of action:
d) type and location of receptor:
e) mechanism of action:
f) physiological role:
g) control of production:
Somatostatin GHRH CRH Luteinizing hormone Testosterone FSH Vasopressin
Cortisol Thyroxine MSH Thyroid Releasing Hormone IGF-I Somatotropin Oxytocin
Prolactin Thyrotropin Corticotropin Glucagon
Hormone 3: Name (of hormone) ________________________________________________
a) chemical class:
b) anatomical site of production:
c) anatomical site of action:
d) type and location of receptor:
e) mechanism of action:
f) physiological role:
g) control of production:
Fill in the blanks (5 pts; 1 pt per blank).
2. Sertoli cells exist in the ___________ tubules, a compartment separated
from the vascular space of the testis by a basement membrane. During adult
functioning they respond to the binding of ______________ by producing
two major protein products. One product, ________________________, is secreted
into the lumen of the tubules where it helps to maintain high levels of
testosterone that are crucial to sperm production. The other product, ______________,
is secreted into the basal compartment outside the blood-testis barrier
from which it diffuses into the blood system and circulates back to the
pituitary where it acts on the ___________________ to selectively decrease
FSH production.
Multiple choice (26 points); circle all that apply.
3. Proopiomelanocortin is broken down rapidly in the adult corticotrope
to all the following:
a) CLIP
b) ACTH
c) -Lipotropin
d) -MSH
e) ß-Endorphin
4. If a biological response to an organ extract requires hours to days
to occur, what group of hormones would you attempt to purify first to identify
the hormone responsible?
a) amino acid derivative neurotransmitters
b) prostaglandins
c) small peptides
d) steroids
e) proteins
5. Prolactin, thyrotopin and somatotropin:
a) are all produced in the neurohypophysis.
b) all share similar -subunits.
c) are all controlled by somatostatin and TRH in acromegalic individuals.
d) all help maintain processes essential to mammalian growth.
6. During post-translational modifications of protein and peptide hormones
in the endoplasmic reticulum and the Golgi apparatus, what does not take
place?
a) intron excision
b) leader sequence cleavage
c) carbohydrate side-chain addition
d) folding into secondary and tertiary structures
7. Luteinizing hormone, follicle-stimulating hormone and chorionic gonadotropin:
a) each act on distinct cell types.
b) all act via cyclic-3',5'-adenosine monophosphate mediated mechanisms.
c) all possess the same ß-subunit within a species.
d) all are secreted proteins.
8. The hypothalamus
a) produces both stimulatory and inhibitory peptides.
b) lies at the base of the brain and surrounds part of the second ventricle.
c) contains several different groupings (nuclei) of neuroendocrine cells.
d) receives inputs from the both the thalamus and the cortex of the
brain.
9. (12 pts; 3 each -- 1 for T/F, 2 for defense) True or False, defend
your answers. (Be brief!)
T F a) A hormone's complete function is always given by its name or
the meaning of its name.
T F b) Immunoassays provide the same information as bioassays.
T F c) All endocrine stimuli result from secretions within the body.
T F d) The definition of a hormone applies to all those chemicals that
circulate in the body at concentrations below microgram levels.
10. Tumors may secrete hormones of a wide variety of types. But often
only a single hormone is made and released. Circle the correct conclusions
given the following observations or ignore this question entirely.
a) Injecting antibodies against the hormone produced by the tumor blocks
growth of the tumor without interfering with normal physiological function,
therefore the hormone produced by the tumor was a unique autocrine signal
or induced an incremental change in normal function that supported tumor
growth.
b) Loss of a smooth cell contour in culture often indicates disorganization
of the cell cytoskeleton, often in response to elevations in intracellular
cAMP. When cells from a tumor under study are cultured in the laboratory
in the presence of cholera toxin they demonstrate loss of cell shape or
control over the cytoskeleton. Moreover, in the presence of a hormone such
as epinephrine that normally causes a similar cellular shape change and
another hormone, somatostatin, that inhibits the epinephrine induced shape
change, further addition of pertussis toxin allows the shape change to
occur. Therefore, the tumor cell must be responding via phospholipase C
activation and subsequent activation of protein kinase C.
c) Serum drained from the immediate area of the tumor stimulates the
formation of blood vessels in the yolk sac of chicken eggs. Serum drained
from sites distant from the tumor, do not stimulate such vessel growth.
When the near-tumor serum is passed through a membrane selectively permeable
only to low molecular weight substances before it is applied to eggs no
blood vessels form. When the serum is extracted with a solvent and the
solvent extract is dried, redissolved in water and applied to eggs, no
vessels form. If the serum is boiled prior to applying it to eggs, vessels
also do not form. It is concluded that the hormone produced is a protein,
that it probably acts on chicken cells via activation of phospholipase
C, a tyrosine kinase activity, protein kinase C, and activation of transcription
factors such as the products of the myc, fos, and jun genes.
d) Removal of the ovaries minimizes tumor growth while administration
of steroid-containing birth control pills prior to ovariectomy increase
the rate of tumor growth, therefore the tumor is steroid dependent and
contains intracellular receptors for steroids like those in the birth control
pills.
e) Measurement of the protein hormone produced by the tumor under study
indicates that the levels in circulation rise when TRH (thyrotropin releasing
hormone) is given and fall when T4 (thyroxine) is given. Moreover,
if two similar sized doses of TRH are given close together, the first causes
a large rise in protein hormone level while the latter causes only a small
additional rise in hormone level. It is concluded that systematic control
over tumor production of the protein hormone does exist in the form of
a positive feedback loop, and that TRH actions in the tumor cell involve
up regulation of receptors.
Essay Question. Choose either #11 or #12 (15 points).
11. What is the importance to the whole organism of the anatomical position
and organization of the hypothalamus and its vascular supply to the anterior
pituitary? How would you go about proving that a hormone is produced in
the pituitary and acts in the hypothalamus rather than the other way around?
12. The ratio of biological potency per unit mass of LH over immunological
reactivity per unit mass of LH changes over the course of a woman's ovarian
cycle. Likewise, the ratio also changes during the course of menopause
during which the ovaries cease to function in the production of steroids
and gametes. What would you expect the pattern of LH secretion to do during
the menopause in terms of both immunologically reactive LH and bioassayable
LH? Provide a reason for the difference between the two measures of LH
in this situation.
Biology 317/319 Endocrinology Exam II [Date B]
Name______________________________
General Instructions: There are 100 points on this exam; 90 on
objective or short answer and 10 on essays. The exam has 8 pages. Budget
your time, read instructions carefully, and good luck.
Fill in the blanks, 7 points.
1. Genes that are expressed in a controlled and timely manner but that
have been demonstrated to be closely related to genes found in neoplasms
are often referred to as ____________________. Chemical, radiation or virus
induced alterations in the structure or positioning of these normal genes
lead to the production of _______________ that are often transcribed and
translated into proteinaceous _________________ ___________________. These
latter proteins have frequently been demonstrated to be inappropriately
expressed or modified forms of elements involved in the mechanisms of action
of ____________ ___________, such as IGF, EGF, PDGF, CSF. Most, in fact,
seem associated with those mechanisms using the key phosphorylating enzymatic
activities ______________ _____________, ______________ _______________
______, ________________ _________________, src gene product, and the GTP-binding
protein Ras gene product.
2. (15 points, 3 each -- 1 for T/F, 2 for defense) True or False,
defend your answers. (Be brief!)
T F a) A hormone's complete function is always given by its name or
the name's meaning.
T F b) Male gamete production depends only on LH levels.
T F c) The major control for hCS/hPL levels is placental growth.
T F d) Hypoplasia is the opposite of hypertrophic.
T F e) The arcuate and the paraventricular nuclei both produce oxytocin.
3. (10 points, 2 each) What do the groups given below have in common?
a) IGF-I, EGF, and colony-stimulating-factor
b) diacylglyceride; 3',5'-cyclic adenosine monophosphate; inositol-1,3,5-triphosphate
c) FSH, cholera toxin, GMP-PNP
d) tyrosine, serine, threonine
e) v-oncogenes, Rb protein mutants, radiation, chemical mutagens
Multiple choice (30 points); circle all that apply.
4. Prolactin, thyrotopin and somatotropin:
a) are all produced in the adenohypophysis.
b) all share similar -subunits.
c) are all controlled by somatostatin and TRH in acromegalic individuals.
d) all help maintain processes essential to mammalian growth.
5. During post-translational modifications of protein and peptide hormones
in the endoplasmic reticulum and the Golgi apparatus, what does not take
place?
a) intron excision
b) leader sequence cleavage
c) carbohydrate side-chain addition
d) folding into secondary and tertiary structures
6. Luteinizing hormone, follicle-stimulating hormone and chorionic gonadotropin:
a) each act on distinct cell types.
b) all are glycoproteins.
c) all possess the same -subunit within a species.
d) all are secreted proteins.
e) all act via cyclic-3',5'-adenosine monophosphate mediated mechanisms.
7. The hypothalamus
a) produces both stimulatory and inhibitory peptides.
b) lies at the base of the brain and surrounds part of the first ventricle.
c) contains several different groupings (nuclei) of neuroendocrine cells.
d) receives inputs from the both the thalamus and the cortex of the brain.
e) supplies factors to the pituitary via the portal plexus.
8. Activation of a phosphoinositide turnover mediated mechanism:
a) involves production of multiple intracellular messages
b) involves alteration in the substrate specificity of phospholipase A2
c) involves lowering the calcium ion concentration required to activate protein kinase C
d) involves a GTP-binding protein
e) has thus far been implicated only in the actions of gonadotropins
f) utilizes phospholipids that are part of the cell membrane
g) is dependent on the actions of phospholipase C
9. Adenylate cyclase:
a) is the enzyme responsible for the generation of cGMP from GTP.
b) can be both stimulated and inhibited by GTP-binding proteins.
c) helps generate a cellular protein phosphorylation response to hormone binding.
d) is located within the nucleus of the cell.
e) binds to the -subunit of Gs subsequent to hormone binding
to receptor.
Fact Table
10. (28 points) Select two hormones from the list below that differ
in the classes of mechanisms of action on target cells that they utilize.
Describe each of these hormones with respect to: a) chemical class of hormone,
b) anatomical site of production (be as precise as possible), c) anatomical
site of action, d) type and cellular location of receptor utilized, e)
mechanism of action (indicate the key transducer(s) and/or effector(s)
involved), f) physiological role within the body, and g) usual endogenous
method of control or regulation of production of the hormone.
Somatostatin, GHRH, CRH, Luteinizing hormone, Testosterone, FSH, Thyrotropin,
IGF-I, Thyroid Releasing Hormone, Somatotropin, Estradiol
Hormone 1: Name (of hormone) ________________________________________________
a) chemical class:
b) anatomical site of production:
c) anatomical site of action:
d) type and location of receptor:
e) mechanism of action:
f) physiological role:
g) control of production:
Hormone 2: Name (of hormone) ________________________________________________
a) chemical class:
b) anatomical site of production:
c) anatomical site of action:
d) type and location of receptor:
e) mechanism of action:
f) physiological role:
g) control of production:
11. Circle the correct conclusions given the following observations
or ignore this question entirely. Tumors may secrete hormones of a
wide variety of types. But often only a single hormone is made and released.
a) Injecting antibodies against the hormone produced by the tumor blocks
growth of the tumor without interfering with normal physiological function,
therefore the hormone produced by the tumor was a unique autocrine signal
or induced an incremental change in normal function that supported tumor
growth.
b) Loss of a smooth cell contour in culture often indicates disorganization
of the cell cytoskeleton, often in response to elevations in intracellular
cAMP. When cells from a tumor under study are cultured in the laboratory
in the presence of cholera toxin they demonstrate loss of cell shape or
control over the cytoskeleton. Moreover, in the presence of a hormone such
as epinephrine that normally causes a similar cellular shape change and
another hormone, somatostatin, that inhibits the epinephrine induced shape
change, further addition of pertussis toxin allows the shape change to
occur. Therefore, the tumor cell must be responding via phospholipase C
activation and subsequent activation of protein kinase C.
c) Serum drained from the immediate area of the tumor stimulates the
formation of blood vessels in the yolk sac of chicken eggs. Serum drained
from sites distant from the tumor, do not stimulate such vessel growth.
When the near-tumor serum is passed through a membrane selectively permeable
only to low molecular weight substances before it is applied to eggs no
blood vessels form. When the serum is extracted with a solvent and the
solvent extract is dried, redissolved in water and applied to eggs, no
vessels form. If the serum is boiled prior to applying it to eggs, vessels
also do not form. It is concluded that the hormone produced is a protein,
that it probably acts on chicken cells via activation of phospholipase
C, a tyrosine kinase activity, protein kinase C, and activation of transcription
factors such as the products of the myc, fos, and jun genes.
d) Removal of the ovaries minimizes tumor growth while administration
of steroid-containing birth control pills prior to ovariectomy increase
the rate of tumor growth, therefore the tumor is steroid dependent and
contains intracellular receptors for steroids like those in the birth control
pills.
e) Measurement of the protein hormone produced by the tumor under study
indicates that the levels in circulation rise when TRH (thyrotropin releasing
hormone) is given and fall when T4 (thyroxine) is given. Moreover,
if two similar sized doses of TRH are given close together, the first causes
a large rise in protein hormone level while the latter causes only a small
additional rise in hormone level. It is concluded that systematic control
over tumor production of the protein hormone does exist in the form of
a positive feedback loop, and that TRH actions in the tumor cell involve
up regulation of receptors.
Essay, 10 points; choose one of 12-14.
12. What sense does it make to have two opposite forms of control loops
operating simultaneously to control gonadotropin levels during the nonfertile
mammalian female reproductive cycle? Illustrate the opposing control loops
and the timing of their maximal function. Also indicate the end result,
if any, of each of the loops' operation.
13. Given that male potency is dependent on adequate circulating testosterone
levels, describe why the design and implementation of a male contraceptive
drug/pill compatible with continued sexual activity is so difficult relative
to that for a female. (Concentrate on physiological rather than sociological
aspects of the problem.)
14. Discuss how endocrinologically-based dwarfism can arise. Try to provide at least three pathways to the condition.