Receptors, Signaling, Hypothalamic, and Pituitary Hormones Flashcards
(88 cards)
1
Q
Pharmacologic name for growth hormone
A
Somatotropin
2
Q
Pharmacologic name for insulin growth factor-1 agonist
A
Mecasermin
3
Q
Pharmacologic somatostatin analogs
A
Octreotide
Lanreotide
4
Q
Pharmacologic GH antagonist
A
Pegvisomat
5
Q
Pharmacologic FSH and analogs
A
Follitropin alpha and beta
Urofollitropin
6
Q
Pharmacologic LH analog
A
Lutropin alpha
7
Q
Pharmacologic hCG analog
A
Choriogonadotropin alpha
8
Q
Pharmacologic GnRH analogs
A
Leuprolide Gonadorelin Goserelin Buserelin Histrelin Nafarelin Triptorelin
9
Q
Pharmacologic GnRH antagonists
A
Ganirelix, cetrorelix
Degarelix, abarelix
10
Q
Oral dopamine receptor agonist used predominantly in the therapy of Parkinson disease, but which has other activities including inhibition of prolactin and growth hormone release which has led to its use in acromegaly, infertility, and galactorrhea
A
Bromocriptine
11
Q
Ergot medication used to tx high levels of prolactin hormone, works by blocking its release from the pituitary gland
A
Cabergoline
12
Q
Pharmacologic vasopressin receptor agonists
A
Vasopressin
Desmopressin
13
Q
Vasopressin receptor antagonists
A
Conivaptan
Tolvaptan
14
Q
What type of receptor, effectors, and signaling pathways are utilized by insulin?
A
Receptor tyrosine kinase
Effectors: tyrosine kinases, IRS-1 to IRS-4
Signaling pathways: MAP kinases, PI 3-kinase, RSK
15
Q
What type of receptor, effectors, and signaling pathways are utilized by GH and PRL?
A
Cytokine receptor-linked kinase
Effectors: JAK, tyrosine kinases
Signaling pathways: STAT, MAP kinase, PI 3-kinase, IRS-1, IRS-2
16
Q
What type of receptor, effectors, and signaling pathways are utilized by TGF-beta?
A
Serine kinase
Effectors: serine kinase
Signaling pathways: Smads
17
Q
What type of receptor, effectors, and signaling pathways are utilized by the following:
Beta-adrenergic LH, FSH, TSH Glucagon PTH, PTHrP ACTH GHRH, CRH
A
GPCRs!
Effectors: Ga(s)»_space;»»> Ca2+ channels
Signaling pathways: stimulation of cAMP»_space;»»> Calmodulin, Ca2+ dependent kinases
18
Q
What type of receptor, effectors, and signaling pathways are utilized by the following:
Alpha-adrenergic
Somatostatin
A
GPCR
Effectors: Ga(i)
Signaling pathways: inhibition of cAMP production, activation of K+, Ca2+ channels
19
Q
What type of receptor, effectors, and signaling pathways are utilized by the following:
TRH, GnRH
A
GPCRs
Effectors: Ga(q), Ga(11)
Signaling pathways: phospholipase C, DAG, IP3, protein kinase C, voltage-gated Ca++ channels
20
Q
The ______________ receptor superfamily is a large and heterogenous group of membrane receptors that respond mainly to protein mediators (e.g., insulin, GH, PRL, TGF-beta) and effects are at the level of gene transcription
A
Kinase-linked
[this superfamily of receptors plays a major role in controlling cell division, growth, differentiation, inflammation, tissue repair, apoptosis, and immune responses]
21
Q
Main types of kinase-linked receptors in endocrine signaling
A
Receptor tyrosine kinases (RTKs)
Serine/threonine kinase receptors
Cytokine receptors
22
Q
What kind of kinase-linked receptor lacks intrinsic enzyme activity bu, when activated, associate with and activate cytosolic kinases?
A
Cytokine receptors
23
Q
Kinase signaling cascade mechanism
A
Often, ligand binding to kinase-linked receptors leads to receptor dimerization (interaction between 2 separate receptors)
The close association of the 2 intracellular kinase domains allows autophosphorylation of intracellular tyrosine residues to occur, which serve as high-affinity binding sites for intracellular proteins that form the next step in the signal transduction cascade
The end result is to activate or inhibit (via phosphorylation) a variety of transcription factors that induce or suppress the expression of specific genes
24
Q
G-proteins consist of 3 subunits: alpha, beta, and gamma. The alpha-subunit binds to _____ nucleotides, activates effector proteins when bound to GTP, and has enzymatic activity (catalyzes the conversion of GTP to GDP resulting in alpha subunit activation)
The beta and gamma subunits form a _____ and remain together as a complex that confers both membrane localization of the G-protein and directs signaling such as activation of ion channels and binding sites for G-protein receptor kinases
A
Guanine
Dimer
25
_______ = enzyme responsible for cAMP production
______ = enzyme responsible for IP3 and DAG formation
Ion channels (particularly calcium and potassium) and the __________ system (controls activity of many signaling pathways influencing cell growth and proliferation, smooth muscle contraction, etc.)
Adenylyl cyclase
Phospholipase C
Rho A/Rho kinase
26
3 main domains that make up the primary structure of most nuclear receptors
Activation function 1 (AF1)
DNA-binding domain (DBD) — highly conserved and functions to recognize and bind specific sequences of DNA (called hormone response elements) upstream of target gene; also plays a role in receptor dimerization
Ligand-binding domain (LBD) — C-terminal LBD selectively binds to agonists or antagonists and confers ligand-dependent activation. Upon ligand binding, LBD undergoes conformation change allowing recruitment of coactivators or corepressors that either activate or repress gene transcription, respectively
27
2 main classes of nuclear receptors
Classic steroid nuclear receptor (GR, MR, ER, PR, AR)
The remaining nuclear receptors include those that bind retinoids, thyroid hormone, vitamin D, xenobiotics, androstane, lipids, and fatty acids
28
_______ and hormones in the _____ family can stimulate prolactin release
TRH; glucagon
[hormonees in glucagon family include secretin, glucagon, VIP, GIP]
29
What is SRIF?
Somatotropin release-inhibiting factor (somatostatin) — hypothalamic hormone that has inhibitory effect on GH release from anterior pituitary
30
Somatotropin is the recombinant human form of GH (rhGH) used clinically and is identical to the predominant native form of human GH. It is mainly metabolized by the ______ and has an endogenous half life of 20-25 mins, but active blood levels of rhGH persist for 36 hrs. It is a P450 _______
Liver; inducer
31
GH receptors dimerize after binding to GH and activate the ______ signaling pathway (2 molecules are required for activation). Growth promoting effects are mediated through an increase in _____ production
JAK/STAT; IGF-1
32
Effects of GH on musculoskeletal system and carbohydrate metabolism
Stimulates longitudinal bone growth until epiphyses close; has anabolic effects in muscle and catabolic effects in lipid cells
Effects on carb metabolism are mixed. GH and IGF-1 have opposite effects on insulin sensitivity — GH reduces insulin sensitivity (mild hyperinsulinemia), IGF-1 acts through IGF-1 and insulin receptors to lower serum glucose and reduce insulin
33
Clinical uses for GH
GH-deficiency in children: therapy with rhGH allows them to reach normal height (can also be used in kids with short stature d/t Prader-Willi, Turner, Noonan, and idiopathic short stature)
GH-deficiency in adults: therapy with rhGH reverses symptoms such as obesity, reduced muscle mass, asthenia, and reduced CO
Wasting in pts with AIDS
Patients with short bowel syndrome who are dependent on total parenteral nutrition
34
GH toxicities in kids vs. adults
Tx is well tolerated in kids; rare AEs include intracranial HTN (manifested by vision changes, HA, nausea, or vomiting), scoliosis, otitis media in pts with Turner syndrome, hypothyroidism, pancreatitis, gynecomastia
Adults have more adverse effects than children, including peripheral edema, myalgias, arthralgias, carpal tunnel syndrome
35
Contraindication to GH use
Known malignancy
36
GH exercises its growth effects by stimulating IGF-1 synthesis in the liver and by inducing chondrocyte differentation/replication and local production of IGF-1. What medication is used the rare instances where there is GH insensitivity caused by GH receptor defects of GH-inhibiting antibodies?
Injectable recombinant human (rh)IGF-1 (mecasermin)
[used in long-term tx of growth failure and short stature in children with severe primary IGF-1 deficiency, for instance d/t growth hormone deficiency or Laron syndrome (growth hormone insensitivity)]
37
Most common adverse effect of mecasermine
Hypoglycemia (eating 20 minutes before helps prevent)
38
Somatostatin inhibits release of GH, glucagon, insulin, and gastrin, and can be used to treat anterior pituitary adenomas that secrete GH. Why does exogenous somatostatin have limited therapeutic value?
Short duration of action (half-life of 1-3 mins) and effects on multiple secretory systems
[however, longer-acting analogs have been developed! — octreotide and lanreotide]
39
Most widely used SST analog that is 45x more potent than SST in inhibiting GH release, 2x as potent in reducing insulin secretion, also inhibits GHRH and thyrotropin
Octreotide (subcutaneous administration, half life 80 mins) — reduces sxs associated with hormone-secreting tumors: acromegaly, carcinoid syndrome, gastrinoma, glucagonoma, nesidioblastosis, diabetic diarrhea, hypokalemia, achlorhydria (WDHA) syndrome
40
Lanreotide is approved for the tx of _____ and has effects comparable to octreotide.
Acromegaly
41
AEs of SST analogs
GI — diarrhea, nausea, abdominal pain; Gallbladder sludge and gallstones can develop d/t decreased gallbladder contraction and bile secretion
Cardiac — sinus bradycardia, conduction disturbances
Vitamin B12 deficiency
42
Polyethylene glycol derivative of mutant GH that binds GH receptor and allows receptor to dimerize, but does not activate JAKSTAT signaling cascade or stimulate IGF-1 secretion; used to tx acromegaly
Pegvisomant
43
Urofollitropin (uFSH) is purified human FSH extracted from urine of postmenopausal women (no LH activity)
Follitropin alpha and beta are recombinant forms of FSH (rFSH) with amino acid sequences identical to that of human FSH. rFSH preparations have a shorter half life but stimulate estrogen secretion equal to or greater than uFSH (they are more expensive though)
What are the clinical uses of these compounds?
Ovulation induction in pts who previously received pituitary suppression (uFSH)
Ovulation induction in pts in whom the cause of infertility is functional and not caused by primary ovarian failure (rFSH alpha and beta)
Spermatogenesis induction (rFSH alpha)
Development of multiple follicles with assisted reproductive technologies
44
Lutropin alpha is the recombinant form of human LH and is only used in combination with ________ for stimulation of follicular development in infertile women with profound LH deficiency
Follitropin alpha
45
hCG may be extracted and purified from the urine of pregnant females. Choriogonadotropin alpha (rhCG) is a recombinant form of hCG. What is the clinical use of hCG and rhCG?
hCG: Used to induce ovulation and pregnancy in anovulatory, infertile females; tx of hypogonadotropic hypogonadism, spermatogenesis induction with follitropin alpha
rhCG: induces ovulation in infertile females who have been pretreated with FSH; induces ovulation and pregnancy in infertile females when the cause of infertility is functional
46
AEs of tx with hCG or rhCG
Uncomplicated ovarian enlargement (usually resolves spontaneously)
Ovarian hyperstimulation syndrome — characterized by ovarian enlargement, ascites, hydrothorax, hypovolemia, sometimes resulting in shock
Risk for multiple pregnancy is 15-20% in ART pts; multiple pregnancies increases risk for gestational diabetes, preeclampsia, and preterm labor
47
Pulsatile vs. continuous administration of GnRH analogs (like leuprolide)
Pulsatile IV administration every 1-4 hrs induces FSH and LH secretion
Continuous administration induces biphasic response: During the first 7-10 days, an agonist effect results in increased concentrations of gonadal hormones. After that, the continued presence of GnRH results in an inhibitory action that manifests as a drop in the concentration of gonadotropins and gonadal steroids
48
T/F: GnRH analogs are more commonly used for suppression of gonadotropin release
True (although they can occasionally be used for stimulation of gonadotropin production)
49
Clinical situations where stimulation of gonadotropin production by GnRH analogs is useful
Infertility (male or female)
| Diagnosis of LH responsiveness
50
Clinical situations where suppression of gonadotropin production by GnRH analogs is useful
Controlled ovarian hyperstimulation (e.g., to prevent premature ovulation by endogenous LH in IVF pts)
Endometriosis
Uterine leiomyomata (uterine fibroids)
Prostate cancer
Central precocious puberty
51
AEs associated with GnRH analog tx
Continuous tx of women with GnRH analog causes typical sx of menopause including hot flashes, sweats, and headaches. In men, continuous administration causes hot flashes, sweats, edema, gynecomastia, decreased libido, decreased hematocrit, reduced bone density.
Additional AEs include depression, diminished libido, generalized pain, vaginal dryness, breast atrophy, and decreased bone density and osteoporosis with long term use
52
Contraindications to GnRH analogs in women
Pregnancy and breastfeeding
53
T/F: GnRH agonists have been shown to more completely suppress gonadotropin production compared to GnRH antagonists
False, GnRH antagonists more completely suppress
54
Clinical uses for GnRH antagonists Ganirelix and Cetrorelix
Controlled ovarian hyperstimulation procedures
[AEs of GnRH receptor antagonists are similar to GnRH agonists]
55
Clinical uses for GnRH antagonists Abarelix and Degarelix
Used to tx advanced prostate cancer — reduces concentrations of gonadotropins and androgens significantly more rapidly than GnRH agonists and avoids the testosterone surge
[AEs of GnRH receptor antagonists are similar to GnRH agonists]
56
Bromocriptine and cabergoline are dopamine D2 receptor agonists. Which one has longer half life?
Cabergoline (65 hrs vs. 15 hrs)
57
Clinical uses for cabergoline or bromocriptine
Standard tx for hyperprolactinemia
Shrink pituitary PRL-secreting tumors, lower circulating PRL levels, and restore ovulation in 70% of women with microadenomas and 30% of women with macroadenomas
Used alone or in combo with pituitary surgery, radiation therapy, or ocreotide administration to tx acromegaly
58
AEs of dopamine agonists
Nausea, HA, lightheadedness, orthostatic hypotension, fatigue
Psychiatric manifestations occur occasionally
Pulmonary infiltrates with chronic high-dose therapy
59
Contraindications to dopamine agonist therapy
Patients with microadenomas who are pregnant discontinue therapy because microadenoma growth during pregnancy is rare [pts with MACROadenomas who are pregnant will continue therapy]
Not recommended to suppress postpartum lactation d/t increased incidence of stroke or coronary thrombosis
60
Clinical use of oxytocin
Administered IV for initiation and augmentation of labor, and IM for control of postpartum bleeding
61
______ is a long-acting synthetic analog of vasopressin with minimal V1 receptor activity and an antidiuretic-to-pressor ratio 3000x that of vasopressin; also has longer half life
Desmopressin
62
MOA of desmopressin and vasopressin
Activates GPCR V1 receptors (found in vascular smooth muscle cells and mediate vasoconstriction) and V2 receptors (found in renal tubule cells and reduce diuresis through increased water permeability and water resorption in the collecting tubules
Extrarenal V2-like receptors regulate the release of coagulation factor VIII and von willebrand factor (receptor activation leads to release)
63
Desmopressin may be used for tx of coagulopathy in ____ and ____
Hemophilia A; von willebrand disease
64
AEs of desmopressin and vasopressin
HA, nausea, abdominal cramps, agitation, and allergic reactions occur rarely
Overdose —> hyponatremia, seizures
Vasopressin should be used with caution in pts with CAD d/t vasoconstriction
65
MOA of conivaptan and tolvaptan
Antagonists of vasopressin receptors [aka “aquaretics” bc they increase renal free water excretion with little or no change in electrolyte excretion]
Tolvaptan is selective for V2 receptors
Conivaptan is nonselective and blocks V1 and V2
66
In short-term clinical trials in pts with CHF and reduced ejection fraction, _____ decreased body weight and improved dyspnea with no effect on all-cause mortality, CV death, or hospitalization for heart failure
In CHF pts, ______ increases renal free water excretion without a change in systemic vascular resistance
Tolvaptan
Conivaptan
67
Conivaptan and tolvaptan are metabolized by ____
CYP3A4
68
A 38 y/o female presents to the reproductive endocrinologist for ovarian hyperstimulation. She is administered follitropin alpha, a FSH analog. Activation of which of the following signaling pathways most likely mediates the therapeutic efficacy of this drug?
a. cAMP synthesis
b. IP3 production
c. cGMP synthesis
d. tyrosine residue phosphorylation
e. gene transcription
a. cAMP synthesis
69
An 8 y/o healthy female is referred to a pediatric endocrinologist for short stature. Physical examination and karyotype analysis lead to the diagnosis of Turner syndrome. Which of the following agents would be most appropriate?
a. somatotropin
b. somatostatin
c. testerone
d. octreotide
e. cabergoline
a. somatotropin
70
An 8 y/o healthy female is referred to a pediatric endocrinologist for short stature. Physical examination and karyotype analysis lead to the diagnosis of Turner syndrome. She is prescribed appropriate therapy. Activation of which of the following signaling pathways most likely mediates the therapeutic efficacy of this drug?
a. cAMP synthesis
b. IP3 production
c. cGMP synthesis
d. tyrosine residue phosphorylation
e. gene transcription
d. tyrosine residue phosphorylation
71
A 41 y/o male presents to the hospital for irradiation of the hypophysis due to a parasellar tumor. After treatment, therapy with somatropin is started. Which of the following adverse effects is most likely?
a. arthralgias
b. hypoglycemia
c. weight loss
d. osteoporosis
e. dehydration
a. arthralgias
72
A 37 y/o female recently diagnosed with pituitary adenoma undergoes ablative radiation therapy, but the treatment fails to control the patient’s symptoms. Lab tests still show a high level of insulin-like growth factor 1 (IGF-1). Octreotide is prescribed. Which of the following actions most likely mediates the therapeutic effects of the drug in this patient’s disorder?
a. stimulation of GH metabolism
b. inhibition of GH release
c. inhibition of insulin release
d. blockade of GH receptors
e. blockade of TSH receptors
b. inhibition of GH release (somatostatin analog)
73
A 56 y/o male recently diagnosed with carcinoid tumor of the lung started treatment that includes octreotide. He is most likely at increased risk of which of the following adverse effects?
a. drowsiness
b. gallstones
c. hypoglycemia
d. heat intolerance
e. flushing
b. gallstones
74
A 36 y/o male presents with elevated serum levels of IGF-1. A thorough workup results in a diagnosis of acromegaly and he undergoes radiation therapy. Since then, he has been taking octreotide. Addition of which drug would be most appropriate to combine with his current medication?
a. desmopressin
b. leuprolide
c. mecasermin
d. methimazole
e. pegvisomant
e. pegvisomant
75
An 8 y/o male is referred to a pediatric endocrinologist because of growth retardation. Lab tests show increased serum growth hormone levels but very low serum levels of insulin-like growth factor 1 (IGF-1). He is diagnosed with Laron dwarfism. Which of the following drugs would be most appropriate?
a. somatotropin
b. octreotide
c. mecasermin
d. oxandrolone
e. cabergoline
c. mecasermin
76
A 36 y/o female presents with a 2 month history of amenorrhea and a white discharge from her breasts for the past month. Imaging shows a pituitary adenoma. A drug with which of the following mechanisms would be most appropriate?
a. stimulation of dopamine synthesis
b. stimulation of GH metabolism
c. blockade of GH receptors
d. blockade of D2 receptors
e. activation of D2 receptors
e. activation of D2 receptors
77
We prescribe bromocriptine for a woman with primary amenorrhea. Normal menstruation returns about a month after starting therapy. Which of the following statements best describes the mechanisms by which bromocriptine caused its desired effects?
a. blocked estrogen receptors, enhanced gonadotropin release
b. increased FSH synthesis
c. inhibited PRL release
d. stimulated ovarian estrogen and progestin synthesis
e. stimulated GnRH release
c. inhibited PRL release
78
A 55 y/o female is admitted to the emergency department in septic shock. Despite fluid therapy and norepinephrine, she remains hypotensive (80/50 mmHg) and tachycardic (120 bpm). An additional drug is given via IV infusion and her blood pressure increases to 106/75 mmHg. Her pulse is 88 bpm. Which of the following was most likely given to the patient?
a. epinephrine
b. desmopressin
c. phenylephrine
d. dobutamine
e. vasopressin
e. vasopressin
79
A young couple (25-year-old male, 23-year-old female) wants to start a family. They have not conceived after 1 yr of unprotected intercourse. Infertility evaluation revealed no abnormalities in the female partner and low sperm count in the male. Which of the following is a drug that is purified from the urine of postmenopausal women and is used to promote spermatogenesis in infertile men?
```
A. Desmopressin
B. Gonadorelin
C. Goserelin
D. Somatropin
E. Urofollitropin
```
E. Urofollitropin
Spermatogenesis in males requires action of FSH and LH. Urofollitropin, which is purified from urine of postmenopausal women, is used clinically to provide FSH activity
80
A 29-year-old woman in her 41st wk of gestation had been in labor for 12 h. Although her uterine contractions had been strong and regular initially, they had diminished in force during the past hour. Which of the following agents would be used to facilitate this woman’s labor and delivery?
```
A. Dopamine
B. Leuprolide
C. Oxytocin
D. Prolactin
E. Vasopressin
```
C. Oxytocin
Oxytocin is an effective stimulant of uterine contraction that is routinely used to augment labor.
81
A 3-year-old boy with failure to thrive and metabolic disturbances was found to have an inactivating mutation in the gene that encodes the growth hormone receptor. Which of the following drugs is most likely to improve his metabolic function and promote his growth?
```
A. Atosiban
B. Bromocriptine
C. Mecasermin
D. Octreotide
E. Somatropin
```
C. Mecasermin
This child’s condition is d/t the inability of GH to stimulate the production of insulin-like growth factors, the ultimate mediators of GH effects. Mecasermin, a combination of recombinant IGF-1 and the binding protein that protects IGF-1 from immediate destruction, will help correct the IGF deficiency. Because of the inactive GH receptors, somatotropin will not be effective
82
An important difference between leuprolide and ganirelix is that ganirelix
A. Can be administered as an oral formulation
B. Can be used alone to restore fertility to hypogonadal men and women
C. Immediately reduces gonadotropin secretion
D. Initially stimulates pituitary production of LH and FSH
E. Must be administered in a pulsatile fashion
C. Immediately reduces gonadotropin secretion
Leuprolide is an agonist of GnRH receptors, whereas ganirelix is an antagonist. Although both drugs can be used to inhibit gonadotropin release, ganirelix does so immediately, whereas leuprolide does so only after about 1 wk of sustained activity
83
A 27-year-old woman with amenorrhea, infertility, and galactorrhea was treated with a drug that successfully restored ovulation and menstruation. Before being given the drug, the woman was carefully questioned about previous mental health problems, which she did not have. She was advised to take the drug orally. Which of the following is most likely to be the drug that was used to treat this patient?
```
A. Bromocriptine
B. Desmopressin
C. Human gonadotropin hormone
D. Leuprolide
E. Octreotide
```
A. Bromocriptine
??
84
A 3-year-old girl was referred to the genetic counselor by her pediatrician. She presents with short stature (height is 85 cm, –3 standard deviations) and appears to have loose skin on her neck. Cytogenetic testing reveals an XO karyotype. Which of the following drugs will allow her to achieve a higher adult height?
```
A. Adrenocorticotropin (ACTH)
B. Corticotropin-releasing hormone (CRH)
C. Growth hormone-releasing hormone (GHRH)
D. Gonadotropin-releasing hormone (GnRH)
E. Somatropin
```
E. Somatotropin
ACTH is used diagnostically in suspected adrenal insufficiency. CRH is used to distinguish Cushing’s syndrome from ectopic ACTH secretion. GHRH is rarely used as treatment. Its main use is as a diagnostic tool. GnRH can be used to treat infertility. Somatotropin, recombinant human GH, promotes growth in children with Turner’s syndrome (an XO genotype) or chronic renal failure. It also helps with AIDS-associated wasting syndrome
85
A 3-year-old girl presented with hirsutism, breast enlargement, and a height and bone age that was consistent with an age of 9. Diagnostic testing revealed precocious puberty. Which of the following is the most appropriate drug for treatment of this patient’s precocious puberty?
```
A. Atosiban
B. Follitropin
C. Leuprolide
D. Octreotide
E. Pegvisomant
```
C. Leuprolide
In precocious puberty, the hypothalamic-pituitary-gonadal axis becomes prematurely active for reasons that are not understood. Tx involves suppressing gonadotropin secretion with continuous administration of a long-acting GnRH agonist such as leuprolide
86
A 47-year-old man exhibited signs and symptoms of acromegaly. Radiologic studies indicated the presence of a large pituitary tumor. Surgical treatment of the tumor was only partially effective in controlling his disease. At this point, which of the following drugs is most likely to be used as pharmacologic therapy?
```
A. Cosyntropin
B. Desmopressin
C. Leuprolide
D. Octreotide
E. Somatropin
```
D. Octreotide
Octreotide is a somatostatin analog that has some efficacy in reducing the excess GH production that causes acromegaly
87
A 37-year-old woman with infertility due to obstructed fallopian tubes was undergoing ovulation induction in preparation for in vitro fertilization. After 10 d of treatment with leuprolide, the next step in the procedure is most likely to involve 10–14 d of treatment with which of the following?
```
A. Bromocriptine
B. Follitropin
C. Gonadorelin
D. hCG
E. Pergolide
```
B. Follitropin
Once the pts endogenous gonadotropin production ha sbeen inhibited through continuous administration of the GnRH agonist leuprolide, the next step in ovulation induction is the administration of a drug with FSH activity to stimulate follicle maturation. Follitropin is recombinant FSH. The only other drug listed that is used in ovulation induction is hCG, but this is an LH analog
88
A 7-year-old boy underwent successful chemotherapy and cranial radiation for treatment of acute lymphocytic leukemia. One month after the completion of therapy, the patient presented with excessive thirst and urination plus hypernatremia. Laboratory testing revealed pituitary diabetes insipidus. To correct these problems, this patient is likely to be treated with which of the following?
```
A. Corticotropin
B. Desmopressin
C. hCG
D. Menotropins
E. Thyrotropin
```
B. Desmopressin
Pituitary diabetes insipidus results from deficiency in vasopressin. It is treated with desmopressin, a peptide agonist of vasopressin V2 receptors
