Welcome to Part 52 of the ASCP MLS Exam Practice Series, covering Hormones and Endocrine Function Tests. Hormones are powerful chemical messengers that regulate metabolism, growth, reproduction, and stress response. This section explores endocrine system physiology, hormone regulation mechanisms, and the clinical laboratory tests used to diagnose endocrine disorders such as thyroid disease, adrenal dysfunction, and diabetes mellitus.
📘 Key Topics Covered
- Classification of hormones (peptide, steroid, amino acid–derived)
- Mechanism of hormone action and feedback regulation
- Hypothalamic and pituitary hormones
- Thyroid hormones (T3, T4, TSH) and thyroid function testing
- Adrenal hormones (cortisol, aldosterone, catecholamines)
- Pancreatic hormones (insulin, glucagon)
- Gonadal hormones (estrogen, progesterone, testosterone)
- Laboratory testing methods: immunoassay, ELISA, chemiluminescence
- Interpretation of endocrine function profiles
- Clinical correlation in endocrine disorders (hyper/hypo conditions)
🧠 Learning Objectives
By the end of this part, you should be able to:
- Explain the types, functions, and regulation of hormones.
- Identify major endocrine glands and their secreted hormones.
- Interpret results from endocrine function tests.
- Recognize common hormonal disorders and their biochemical markers.
60 MCQs (4061-4120):
- Hormones are best described as:
a) Enzymes that catalyze biochemical reactions
b) Chemical messengers secreted by endocrine glands
c) Vitamins required for metabolism
d) Structural proteins in the cell membrane - Which gland is known as the “master gland”?
a) Thyroid gland
b) Pituitary gland
c) Adrenal gland
d) Pancreas - The primary function of the thyroid gland is to:
a) Regulate calcium levels
b) Control metabolism through hormone secretion
c) Maintain water balance
d) Stimulate immune function - The main thyroid hormones are:
a) T3 and T4
b) TSH and ACTH
c) FSH and LH
d) Insulin and glucagon - The pituitary hormone that stimulates the thyroid gland is:
a) FSH
b) ACTH
c) TSH
d) GH - The adrenal medulla secretes:
a) Cortisol and aldosterone
b) Epinephrine and norepinephrine
c) Insulin and glucagon
d) T3 and T4 - The adrenal cortex secretes all of the following except:
a) Cortisol
b) Aldosterone
c) Epinephrine
d) Androgens - Insulin is produced by:
a) Alpha cells of the pancreas
b) Beta cells of the pancreas
c) Delta cells of the pancreas
d) Adrenal cortex - The primary function of insulin is to:
a) Increase blood glucose
b) Decrease blood glucose
c) Convert glycogen to glucose
d) Stimulate lipolysis - Glucagon increases blood glucose by stimulating:
a) Glycolysis
b) Glycogenolysis and gluconeogenesis
c) Fatty acid synthesis
d) Protein synthesis - Cortisol is secreted by the:
a) Thyroid gland
b) Adrenal cortex
c) Adrenal medulla
d) Pituitary gland - The function of cortisol includes:
a) Decreasing blood glucose
b) Increasing protein synthesis
c) Increasing blood glucose during stress
d) Stimulating insulin secretion - Aldosterone acts mainly on the:
a) Brain
b) Kidney
c) Liver
d) Pancreas - Aldosterone increases:
a) Sodium excretion
b) Potassium retention
c) Sodium reabsorption
d) Water loss - Parathyroid hormone (PTH) regulates the level of:
a) Sodium
b) Calcium
c) Potassium
d) Chloride - Calcitonin and parathyroid hormone (PTH) have:
a) Similar effects on calcium levels
b) Opposite effects on calcium regulation
c) No effect on calcium
d) Identical target organs - Growth hormone (GH) is secreted by the:
a) Thyroid gland
b) Adrenal cortex
c) Anterior pituitary
d) Posterior pituitary - The posterior pituitary stores and releases:
a) ACTH and GH
b) ADH and oxytocin
c) T3 and T4
d) FSH and LH - The primary function of ADH (antidiuretic hormone) is to:
a) Increase water reabsorption in kidneys
b) Stimulate urine production
c) Decrease sodium reabsorption
d) Promote sweating - A deficiency of ADH results in:
a) Diabetes mellitus
b) Diabetes insipidus
c) Addison’s disease
d) Cushing’s syndrome - Which hormone stimulates milk production?
a) Oxytocin
b) Prolactin
c) LH
d) FSH - Which hormone triggers ovulation?
a) FSH
b) LH
c) Estrogen
d) Progesterone - Which hormone maintains pregnancy and prepares the uterus for implantation?
a) LH
b) Estrogen
c) Progesterone
d) Oxytocin - The main male sex hormone is:
a) Progesterone
b) Estrogen
c) Testosterone
d) Cortisol - Cushing’s syndrome is associated with:
a) Decreased cortisol
b) Increased cortisol
c) Decreased aldosterone
d) Increased insulin - Addison’s disease is caused by:
a) Hyperfunction of adrenal cortex
b) Hypofunction of adrenal cortex
c) Hyperthyroidism
d) Pituitary tumor - Hypothyroidism results in:
a) Increased metabolic rate
b) Decreased metabolic rate
c) High body temperature
d) Weight loss - Hyperthyroidism is characterized by:
a) Fatigue, weight gain, cold intolerance
b) Weight loss, heat intolerance, tremors
c) Edema and hypoglycemia
d) Bradycardia and low body temperature - Laboratory diagnosis of thyroid disorders commonly includes measurement of:
a) T3, T4, and TSH
b) Cortisol and ACTH
c) Insulin and glucagon
d) GH and prolactin - In the endocrine system, feedback control ensures:
a) Random hormone release
b) Constant hormone overproduction
c) Regulation and balance of hormone secretion
d) Permanent suppression of hormones - A patient has the following thyroid profile: decreased total T4, decreased free T4, positive thyroid peroxidase antibody, and increased TSH. This patient most probably has:
a) Hyperthyroidism
b) Hypothyroidism
c) A normal thyroid
d) Graves’ disease - The hormone that triggers ovulation is:
a) Follicle-stimulating hormone (FSH)
b) Luteinizing hormone (LH)
c) Thyroid-stimulating hormone (TSH)
d) Human chorionic gonadotropin (HCG) - During a normal pregnancy, quantitative human chorionic gonadotropin (HCG) levels peak at how many weeks after the last menstrual period?
a) 2–4
b) 8–10
c) 14–16
d) 18–20 - A 68-year-old female patient tells her physician of being “cold all the time” and recent weight gain. A TSH level is 8.7 μU/mL (reference range = 0.5-5.0). This most likely indicates:
a) Primary hypothyroidism
b) Graves’ disease
c) A TSH-secreting tumor
d) Primary hyperthyroidism - The majority of thyroxine (T4) is converted into the more biologically active hormone:
a) Thyroglobulin
b) Thyroid-stimulating hormone (TSH)
c) Triiodothyronine (T3)
d) Thyrotropin-releasing hormone - The recommended initial thyroid function test for a patient with symptoms which may be related to a thyroid disorder is:
a) Free thyroxine (free T4)
b) Thyroid-stimulating hormone (TSH)
c) Total thyroxine (T4)
d) Triiodothyronine (T3) - The screening test for congenital hypothyroidism in newborns is based upon the level of:
a) Free T4
b) Thyroid-binding globulin
c) Thyroid-releasing hormone
d) Total thyroxine (T4) or TSH - A 45-year-old woman has symptoms of muscle weakness, racing heart, and sweating. Total and free T4 are abnormally high. If the TSH is markedly decreased, this is consistent with:
a) Graves’ disease
b) An adenoma of the thyroid
c) Panhypopituitarism
d) Primary hypothyroidism - TSH is produced by the:
a) Hypothalamus
b) Pituitary gland
c) Adrenal cortex
d) Thyroid gland - The most common form of congenital adrenal hyperplasia (95%) is 21-hydroxylase deficiency, which is detected by elevated plasma levels of:
a) Cortisol
b) Aldosterone
c) 17-OH-progesterone
d) 11-deoxycortisol - The screen for adrenal cortical hyperfunction with the greatest sensitivity and specificity is:
a) 24-hour urine free cortisol
b) Plasma cortisol
c) Urinary 17-hydroxycorticosteroids
d) Plasma corticosterone - Plasma for cortisol determinations is collected at 7 AM and 10 PM. A higher cortisol level in the morning sample is consistent with:
a) A normal finding
b) Cushing syndrome
c) Addison disease
d) Hypopituitarism - The major action of angiotensin II is:
a) Increased pituitary secretion of vasopressin
b) Increased vasoconstriction
c) Increased parathormone secretion
d) Decreased adrenal secretion of aldosterone - Aldosterone is released by the adrenal cortex upon stimulation by:
a) Renin
b) Angiotensinogen
c) Angiotensin I
d) Angiotensin II - A diagnosis of primary adrenal insufficiency (Addison’s disease) requires demonstration of:
a) Decreased urinary 17-keto- and 17-hydroxysteroids
b) Decreased cortisol production
c) Impaired response to ACTH stimulation
d) Increased urinary cortisol excretion after metyrapone - How is primary hypocortisolism (Addison’s disease) differentiated from secondary hypocortisolism (of pituitary origin)?
a) ACTH is decreased in primary and elevated in secondary.
b) ACTH is elevated in primary and decreased in secondary.
c) Low aldosterone and hypoglycemia are present only with secondary.
d) Normal cortisol levels are seen with primary. - The urinary excretion product measured as an indicator of epinephrine and norepinephrine production is:
a) Dopamine
b) Dihydroxyphenylalanine (DOPA)
c) Homovanillic acid (HVA)
d) Vanillylmandelic acid (VMA) - 24-hour homovanillic acid (HVA) is usually ordered to help in the diagnosis of:
a) Cushing disease
b) Malignant neuroblastoma
c) Conn disease
d) Graves disease - The biologically most active, naturally occurring androgen is:
a) Androstenedione
b) Cortisol
c) Epiandrosteronee
d) Testosterone - Which of the following is secreted by the placenta and used for the early detection of pregnancy?
a) Follicle-stimulating hormone (FSH)
b) Human chorionic gonadotropin (HCG)
c) Luteinizing hormone (LH)
d) Progesterone - During pregnancy, the form of estrogen that predominates and may be useful in prenatal screening is:
a) Estradiol
b) Estriol
c) Estrone
d) Pregnanediol - A patient has the following laboratory findings: increased serum calcium, decreased serum phosphate, and increased parathyroid hormone. This patient most likely has:
a) Hyperparathyroidism
b) Hypoparathyroidism
c) Nephrosis
d) Steatorrhea - Test methodology for monitoring parathyroid glandular function should be focused on assessing:
a) Intact PTHrP molecule
b) The C-terminal PTH
c) Intact PTH (amino acids 1-84)
d) N-terminal PTH (amino acids 1-7) - A patient with signs and symptoms suggestive of acromegaly would be confirmed if they had which of the following?
a) An elevated serum phosphate concentration
b) A decreased serum growth hormone releasing factor
c) No decrease in serum growth hormone 90 minutes after oral glucose
d) An increased serum somatostatin concentration - Which sample collection would give an accurate assessment of potential excess cortisol production (hypercortisolism)?
a) Collect plasma at 8 AM only.
b) Collect a 24-hour urine free cortisol.
c) Collect plasma at 8 AM and 8 AM the next day.
d) Collect plasma 1 hour after metyrapone administration. - Estrogen and progesterone receptor assays are useful in identifying patients with which cancer who are likely to benefit from endocrine therapy?
a) Ovarian cancer
b) Breast cancer
c) Endometriosis
d) Amenorrhea - A patient with a 16-week MSAFP level that is significantly lower than the median is most at risk for:
a) A neural tube defect
b) Multiple birth (twins)
c) A trisomy disorder like Down syndrome
d) A normal pregnancy - Which of the following sets of results is consistent with primary hypothyroidism (e.g., Hashimoto thyroiditis)?
a) TSH decreased, free T4 decreased, antithyroglobulin antibody positive
b) TSH increased, free T4 increased, antithyroglobulin antibody positive
c) TSH normal, free T4 decreased, antithyroglobulin antibody negative
d) TSH increased, free T4 decreased, antithyroglobulin antibody positive - The common substrate used in the biosynthesis of all adrenal steroids, including androgens and estrogens, is:
a) Cortisol
b) Catecholamines
c) Progesterone
d) Cholesterol - Which adrenal cortical hormone is a potent mineralocorticoid that regulates sodium and potassium balance?
a) Cortisol
b) Aldosterone
c) Corticosterone
d) Dehydroepiandrosterone (DHEA)
📌 How to Use This Practice Set
- Answer each question before checking the key.
- Focus on why the correct answer is right and the others are wrong.
- Use this set as timed practice to simulate the real exam environment.
Answer Key
Answer Key:
- b) Chemical messengers secreted by endocrine glands
- b) Pituitary gland
- b) Control metabolism through hormone secretion
- a) T3 and T4
- c) TSH
- b) Epinephrine and norepinephrine
- c) Epinephrine
- b) Beta cells of the pancreas
- b) Decrease blood glucose
- b) Glycogenolysis and gluconeogenesis
- b) Adrenal cortex
- c) Increasing blood glucose during stress
- b) Kidney
- c) Sodium reabsorption
- b) Calcium
- b) Opposite effects on calcium regulation
- c) Anterior pituitary
- b) ADH and oxytocin
- a) Increase water reabsorption in kidneys
- b) Diabetes insipidus
- b) Prolactin
- b) LH
- c) Progesterone
- c) Testosterone
- b) Increased cortisol
- b) Hypofunction of adrenal cortex
- b) Decreased metabolic rate
- b) Weight loss, heat intolerance, tremors
- a) T3, T4, and TSH
- c) Regulation and balance of hormone secretion
- b) Hypothyroidism
- b) Luteinizing hormone (LH)
- b) 8–10
- a) Primary hypothyroidism
- c) Triiodothyronine (T3)
- b) Thyroid-stimulating hormone (TSH)
- d) Total thyroxine (T4) or TSH
- a) Graves’ disease
- b) Pituitary gland
- c) 17-OH-progesterone
- a) 24-hour urine free cortisol
- a) A normal finding
- b) Increased vasoconstriction
- d) Angiotensin II
- c) Impaired response to ACTH stimulation
- b) ACTH is elevated in primary and decreased in secondary.
- d) Vanillylmandelic acid (VMA)
- b) Malignant neuroblastoma
- d) Testosterone
- b) Human chorionic gonadotropin (HCG)
- b) Estriol
- a) Hyperparathyroidism
- c) Intact PTH (amino acids 1-84)
- c) No decrease in serum growth hormone 90 minutes after oral glucose
- b) Collect a 24-hour urine free cortisol.
- b) Breast cancer
- c) A trisomy disorder like Down syndrome
- d) TSH increased, free T4 decreased, antithyroglobulin antibody positive
- d) Cholesterol
- b) Aldosterone
Top 8 Medical Laboratory Scientist (MLS) Exams:
Top 8 Medical Laboratory Scientist (MLS) Exams that are recognized globally and can help professionals validate their credentials and enhance their career opportunities:
1. ASCP – American Society for Clinical Pathology (USA)
- Exam Name: MLS(ASCP)
- Eligibility: Bachelor’s degree with clinical laboratory experience.
- Global Recognition: High
- Purpose: Certifies Medical Laboratory Scientists in the United States and internationally.
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- Exam Name: MLT(AMT) or MT(AMT)
- Eligibility: Academic and/or work experience in medical laboratory technology.
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- Exam Name: AIMS Certification Exam
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- Recognition: Required for practice in Australia.
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4. CSMLS – Canadian Society for Medical Laboratory Science
- Exam Name: CSMLS General or Subject-specific Exams
- Eligibility: Graduation from a CSMLS-accredited program or equivalent.
- Recognition: Canada
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