Hormones I

The placenta secretes numerous hormones, both protein and steroid. Which of the following hormones is not secreted by the placenta?

 

Human placental lactogen (HPL)

 

Progesterone

 

Estrogen

 

Luteinizing hormone (LH)

 

Human chorionic gonadotropin (HCG)

• Luteinizing hormone (LH)

The FINAL metabolite of epinephrine that is measured in urine is:

 

Dopamine

 

Homovanillic acid

 

Metanephrines

 

Vanillylmandelic acid

• Vanillylmandelic acid

The test for adrenal cortical hyperfunction that has the greatest diagnostic sensitivity is measurement of:

 

Plasma cortisol

 

Plasma corticosterone

 

Urinary free cortisol

 

Urinary 17-hydroxycorticosteroids

• Urinary Free Cortisol

As a screening test for Cushing's syndrome, the physician wishes to see whether a patient exhibits normal diurnal rhythm of his cortisol secretion. At what time should the specimens be drawn for plasma cortisol determination? (Assume a daytime work schedule for the patient.)

 

Noon, midnight

 

8 AM, 8 PM

 

6 AM, noon

 

Noon, 6 PM

 

8 AM, 2 PM

• 8 AM, 8 PM

In a patient who is suspected of having pheochromocytoma, measurement of which of the following urinary compounds would be the most useful?

 

Catecholamines

 

Vanillylmandelic acid

 

Homovanillic acid

 

Metanephrines

 

Dopamine

• Metanephrines

Measurement of urinary metanephrine and vanillylmandelic acid (VMA) assesses the amount of hormone secreted by the ................ and is done to detect the presence of ................ .

 

gastrointestinal (GI) tract; carcinoid tumor

 

adrenal medulla; pheochromocytoma

 

adrenal cortex; Cushing syndrome

 

medulla of the brain; neuroblastoma

• adrenal medulla, pheochromocytoma

Which one of the following substances is measured in urine to determine the presence of a gastroenteropancreatic neuroendocrine tumor in an individual with carcinoid syndrome?

 

Metanephrine

 

Homovanillic acid (HVA)

 

5-Hydroxyindole acetic acid (5-HIAA)

 

VMA

• 5-Hydroxyindole acetic acid (5-IAA)

In the assessment of equivocal results in pheochromocytoma testing, the clonidine suppression test is used to differentiate between:

 

increased serotonin production by the GI tract versus serotonin from the brain.

 

adrenal gland and sympathetic nervous system increases in catecholamine synthesis.

 

adrenal gland and GI tract increased synthesis of dopamine.

 

elevated blood pressure caused by pheochromocytoma versus that caused by carcinoid tumor.

• adrenal gland and sympathetic nervous system increases in catecholamine synthesis

Pheochromocytomas:

 

produce hypotension (decreased blood pressure).

 

tend to secrete serotonin in increased amounts.

 

are tumors derived from enterochromaffin cells.

 

are benign in the majority of cases.

• are benign in the majority of cases

The amino acid precursor for the neurotransmitter serotonin (5HT) is:

 

tryptophan.

 

cytosine.

 

threonine.

 

tyrosine.

• tryptophan

Metabolism of norepinephrine and epinephrine in adrenal chromaffin cells requires the presence of which one of the following enzymes for conversion into normetanephrine and metanephrine?

 

Dopamine-beta-hydroxylase

 

Monoamine oxidase

 

Tyrosine hydroxylase

 

Catechol-O-methyltransferase

• Catechol-O-methyltransferase

An overnight fast is recommended for individuals being tested for carcinoid syndrome because:

 

dietary interference, particularly with foods that contain 5-hydroxyindoles, will produce a false increase in plasma 5-HIAA measurement.

 

no food should be present in the GI tract for 12 hours before analysis of catecholamine metabolites.

 

certain foods interfere with the methods of analysis used for serotonin analysis, particularly the high performance liquid chromatography (HPLC) assays.

 

monoamine systems are targets of certain components of foods that contain tyrosine, and a false-negative result will occur in HVA testing.

• dietary interference, particularly in foods that contain 5-hydroxyindole, will produce a false increase in plasma 5-HIAA measurement

The urinary metabolite measured as an indicator of dopamine synthesis is:

 

metanephrine.

 

vanillylmandelic acid.

 

homovanillic acid.

 

catechol-O-methyltransferase.

• Homovanillic acid

The rate-limiting step in the biosynthesis of catecholamines is the:

 

conversion of tryptophan to 5-hydroxytryptophan by tryptophan hydroxylase.

 

metabolism by catechol-O-methyltransferase (COMT) to MHPG.

 

conversion of 3-methoxy-4-hydroxyphenylglycol (MHPG) to VMA by alcohol dehydrogenase.

 

conversion of tyrosine to 3,4-dihydroxyphenylalanine by tyrosine hydroxylase.

• conversion of tyrosine to 3,4-dihydroxylphenylalanine by tyrosine hydroxylase

Currently, the most common method of analysis for plasma catecholamines is:

 

HPLC.

 

spectrophotometry.

 

liquid chromatography (LC) with electrochemical (EC) detection.

 

mass spectrometry.

• liquid chromatography (LC) with electrochemical (EC) detection

All of the following represent metabolic effects caused by the action of epinephrine secreted from the adrenal gland except:

 

bronchodilation.

 

glycogenolysis.

 

increased protein synthesis.

 

increased lipolysis.

• increased protein synthesis

The follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are important in the reproductive function of the male and female and are released in response to:

 

oxytocin.

 

corticotrophin-releasing hormone (CRH).

 

gonadotropin-releasing hormone (GnRH).

 

TSH.

• gonadotropin-releasing hormone (GnRH)

Which one of the following hormones is classified as a glycoprotein?

 

Prolactin

 

Follicle-stimulating hormone

 

Adrenocorticotropic hormone

 

Growth hormone

• Follicle-stimulating hormone

Androgen secretion by the testes is stimulated by:

 

Testosterone

 

Gonadotropins

 

Follicle-stimulating hormone (FSH)

 

Luteinizing hormone (LH)

• Luteinizing hormone (LH)

A genetic disorder causing a deficiency of certain enzymes in the synthetic pathways leading to cortisol and aldosterone production is referred to as:

 

Cushing's syndrome

 

Congenital adrenal hyperplasia

 

Conn's syndrome

 

Addison's disease

• Congenital adrenal hyperplasia

The anterior portion of the pituitary gland synthesizes many protein hormones. Another name for this part of the pituitary gland is the:

 

hypophysis.

 

hypothalamus.

 

adenohypophysis.

 

neurohypophysis.

• adenohypophysis

The hypothalamic hormone that inhibits prolactin is referred to as prolactin-inhibiting hormone but is actually:

 

dopamine.

 

thyrotropin.

 

interleukin 1.

 

adrenaline.

• dopamine

Which one of the following hormones causes the hypothalamus to trigger the surge of luteinizing hormone (LH) from the anterior pituitary just before ovulation?

 

Follicle-stimulating hormone (FSH)

 

Gonadotropin-releasing hormone (GnRH)

 

Progesterone

 

Estrogen

• Estrogen

What would the laboratory results be in a male patient exhibiting characteristic symptoms of hypogonadotropic hypogonadism?

 

Decreased testosterone, decreased FSH

 

Elevated testosterone, decreased FSH

 

Decreased testosterone, elevated FSH

 

Elevated testosterone, elevated FSH

• decreased testosterone, decreased FSH

During the luteal phase, which hormone, when decreased in the absence of conception, releases its inhibition on pituitary gland synthesis and release of FSH?

 

Chorionic gonadotropin

 

Estrone

 

Progesterone

 

Estradiol

• Estradiol

Which one of the following hormones shuts off synthesis and release of LH from the male pituitary gland?

 

Testosterone

 

Prolactin

 

FSH

 

Inhibin

• Testosterone

Inhibin:

 

augments release of LH from the male pituitary gland.

 

inhibits release of FSH from the male pituitary gland.

 

increases in males with elevated GnRH.

 

promotes synthesis of testosterone by the Sertoli cells.

• inhibits release of FSH from the male pituitary gland

For the past 3 weeks, serum estriol levels in a pregnant woman have been steadily increasing. This is consistent with:

 

Congenital cytomegalovirus infection

 

A normal pregnancy

 

Fetal death

 

Hemolytic disease of the newborn

• a normal pregnancy

Which of the following is secreted by the placenta and used for the early detection of pregnancy?

 

Human chorionic gonadotropin (HCG)

 

Luteinizing hormone (LH)

 

Progesterone

 

Follicle-stimulating hormone (FSH)

• Human chorionic gonadotropin (HCG)

In nonpregnant women, progesterone is synthesized and secreted by the:

 

pituitary gland.

 

corpus luteum.

 

placenta.

 

Both a and b are correct.

• Corpus luteum

Typical findings in a woman in menopause include:

 

decreased serum LH/FSH.

 

hirsutism.

 

increased progesterone.

 

decreased estrogen and inhibin.

• decreased estrogen and inhibin

Which one of the following statements regarding FSH/LH is incorrect?

 

FSH acts on the cells of the follicle to increase responsiveness of LH receptors.

 

Progesterone produced by the corpus luteum causes LH levels to increase.

 

LH acts to stimulate Leydig cells in the testes to synthesize testosterone.

 

FSH, secreted by the anterior pituitary, induces follicular maturation.

• progesterone produced by the corpus luteum causes LH levels to increase

Early activation of the hypothalamic-pituitary-gonadal axis in a young child will lead to:

 

GnRH-independent precocious puberty.

 

pseudohermaphroditism.

 

GnRH-dependent precocious puberty.

 

pseudoprecocious puberty.

• GnRH-dependent precocious puberty

In measurement of testosterone in blood:

 

assessment of serum 17-ketosteroids is included.

 

specimens must be collected in EDTA anticoagulant.

 

5-androstenediol derivatives are actually measured.

 

morning specimens are preferred because of the diurnal release of testosterone.

• morning specimens are preferred because of diurnal release of testosterone

Dehydroepiandrosterone sulfate (DHEA-S):

 

is an important screening test used to evaluate women with hirsutism and virilization.

 

concentration is increased in 17-hydroxylase deficiency-caused amenorrhea.

 

analysis is performed using heparinized plasma.

 

concentrations exhibit a circadian rhythm that reflects the secretion of adrenocorticotropic hormone (ACTH).

• is an important screening test used to evaluate women with hirsutism and virillization

The analytical method that provides better analytical sensitivity in hormone detection than other methods such as immunoassay or receptor-based assays is:

 

bioassay.

 

immunometric assay.

 

spectrophotometry.

 

tandem mass spectrometry.

 

• tandem mass spectrometry

The analytical method that provides better analytical sensitivity in hormone detection than other methods such as immunoassay or receptor-based assays is:

 

bioassay.

 

immunometric assay.

 

spectrophotometry.

 

tandem mass spectrometry.

 

Correct answer

• pheochromocytoma

Which one of the following statements concerning steroid hormones is correct?

 

Steroid hormones, because of their structure, are not bound to carrier proteins as they circulate in the As a screening test for Cushing's syndrome blood.

 

Steroid hormones have a very short half-life (usually <30 minutes) in the circulation.

 

Steroid hormones are hydrophobic when free and bind to intracellular receptors in the nucleus.

 

Steroid hormones attach to a receptor on the surface of a cell, which eventually induces enzyme phosphorylation within the cell.

• steroid hormones are hydrophobic when free and bind to intracellular receptors in the nucleus