Podcast
Questions and Answers
What is the primary function of luteinizing hormone (LH) in the reproductive system?
What is the primary function of luteinizing hormone (LH) in the reproductive system?
Which hormone is primarily responsible for inhibiting prolactin secretion?
Which hormone is primarily responsible for inhibiting prolactin secretion?
What is the role of follicle stimulating hormone (FSH) in the reproductive system?
What is the role of follicle stimulating hormone (FSH) in the reproductive system?
What is the main androgen secreted by the ovaries?
What is the main androgen secreted by the ovaries?
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Which cell type is responsible for synthesizing androgens in the ovaries?
Which cell type is responsible for synthesizing androgens in the ovaries?
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How does the liver contribute to the metabolic process of ovarian hormones?
How does the liver contribute to the metabolic process of ovarian hormones?
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Which of the following hormones primarily stimulates breast epithelial cell proliferation?
Which of the following hormones primarily stimulates breast epithelial cell proliferation?
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What condition results from an impairment of hypothalamic control over prolactin secretion?
What condition results from an impairment of hypothalamic control over prolactin secretion?
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What role does progesterone play in early pregnancy?
What role does progesterone play in early pregnancy?
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Which hormone is implicated in negative feedback regarding luteinizing hormone (LH)?
Which hormone is implicated in negative feedback regarding luteinizing hormone (LH)?
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What can be a consequence of hyperprolactinaemia?
What can be a consequence of hyperprolactinaemia?
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What stimulates the production of testosterone in the testes?
What stimulates the production of testosterone in the testes?
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Which statement about sertoli cells is true?
Which statement about sertoli cells is true?
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How does chronic kidney disease affect prolactin levels?
How does chronic kidney disease affect prolactin levels?
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Which of the following is a potential cause of amenorrhoea related to hyperprolactinaemia?
Which of the following is a potential cause of amenorrhoea related to hyperprolactinaemia?
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Which hormone is linked to the development of secondary sexual characteristics in males?
Which hormone is linked to the development of secondary sexual characteristics in males?
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Which condition is primarily defined by excessive hair growth in a male distribution in women?
Which condition is primarily defined by excessive hair growth in a male distribution in women?
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What is the most important androgen involved in hirsutism and virilism?
What is the most important androgen involved in hirsutism and virilism?
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Which of the following conditions is NOT typically associated with virilism?
Which of the following conditions is NOT typically associated with virilism?
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What is commonly elevated in the plasma of individuals with polycystic ovary syndrome?
What is commonly elevated in the plasma of individuals with polycystic ovary syndrome?
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Which of the following symptoms is NOT associated with hyperandrogenism in polycystic ovary syndrome?
Which of the following symptoms is NOT associated with hyperandrogenism in polycystic ovary syndrome?
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In the context of female infertility, what distinguishes primary infertility from secondary infertility?
In the context of female infertility, what distinguishes primary infertility from secondary infertility?
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Which of the following conditions is associated with insulin resistance and elevated plasma insulin concentrations?
Which of the following conditions is associated with insulin resistance and elevated plasma insulin concentrations?
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What percentage of clinically normal menstrual cycles are typically ovulatory in women experiencing infertility?
What percentage of clinically normal menstrual cycles are typically ovulatory in women experiencing infertility?
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What plasma progesterone concentration on day 21 of the luteal phase indicates normal ovulation?
What plasma progesterone concentration on day 21 of the luteal phase indicates normal ovulation?
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Which of the following results suggests hypergonadotrophic hypogonadism?
Which of the following results suggests hypergonadotrophic hypogonadism?
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In a gonadotrophin-releasing hormone (GnRH) test, failure of plasma LH and FSH levels to rise indicates what?
In a gonadotrophin-releasing hormone (GnRH) test, failure of plasma LH and FSH levels to rise indicates what?
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What condition can high plasma prolactin concentrations lead to in females?
What condition can high plasma prolactin concentrations lead to in females?
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What does low serum concentrations of Anti-Müllerian hormone (AMH) indicate?
What does low serum concentrations of Anti-Müllerian hormone (AMH) indicate?
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When conducting thyroid function tests, what common effect is associated with primary hypothyroidism?
When conducting thyroid function tests, what common effect is associated with primary hypothyroidism?
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Which condition should be excluded when monitoring follicular development and ovulation via ultrasound?
Which condition should be excluded when monitoring follicular development and ovulation via ultrasound?
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What is indicated by decreased plasma concentrations of FSH and LH?
What is indicated by decreased plasma concentrations of FSH and LH?
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What is the minimum volume of semen required for proper analysis in male infertility investigations?
What is the minimum volume of semen required for proper analysis in male infertility investigations?
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Which combination of plasma hormone concentrations indicates hypogonadotrophic hypogonadism?
Which combination of plasma hormone concentrations indicates hypogonadotrophic hypogonadism?
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What is a possible indication if the plasma FSH concentration is higher than LH concentration?
What is a possible indication if the plasma FSH concentration is higher than LH concentration?
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If the plasma LH and FSH levels double after a GnRH test, what does this suggest?
If the plasma LH and FSH levels double after a GnRH test, what does this suggest?
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What might be measured to exclude the presence of hyperprolactinaemia in male infertility investigations?
What might be measured to exclude the presence of hyperprolactinaemia in male infertility investigations?
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What is the possible result of an exaggerated response in plasma LH and FSH levels after administering GnRH?
What is the possible result of an exaggerated response in plasma LH and FSH levels after administering GnRH?
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During an hCG stimulation test, what does a rise in plasma testosterone within 72–120 hours suggest?
During an hCG stimulation test, what does a rise in plasma testosterone within 72–120 hours suggest?
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Which specific hormone levels would require a GnRH test due to their low concentrations?
Which specific hormone levels would require a GnRH test due to their low concentrations?
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Study Notes
The Reproductive System
- The reproductive system is responsible for hormone production and maturation of germ cells in the gonads.
- Hypothalamus secretes GnRH (gonadotrophin-releasing hormone) which regulates the release of LH (luteinizing hormone) and FSH (follicle stimulating hormone) from the pituitary gland.
- Dopamine, a neurotransmitter, is also secreted by the hypothalamus and controls prolactin secretion.
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Pituitary gland secretes LH and FSH via basophil cells.
- LH primarily stimulates hormone production in the gonads.
- FSH stimulates the development of germ cells.
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Prolactin, secreted by pituitary acidophil cells, stimulates breast epithelial cell proliferation and induces milk production.
- Prolactin secretion is inhibited by dopamine, unlike other pituitary hormones.
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Ovaries secrete estrogens, progesterone, and androgens.
- Androgens (C19 steroids) are synthesized by theca cells and converted to estrogens (C18 steroids) in granulosa cells.
- Oestradiol is the most important ovarian estrogen
- Oestrogens are important for female secondary sex characteristics and menstruation.
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Progesterone is secreted by the corpus luteum during the luteal phase of the menstrual cycle and during pregnancy.
- It prepares the endometrium for a fertilized ovum.
- It helps maintain early pregnancy.
- It can cause a rise in basal body temperature.
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Testes secrete testosterone.
- Testosterone is produced by Leydig cells and stimulated by LH.
- Testosterone inhibits LH secretion through negative feedback.
- Inhibin, produced by Sertoli cells, controls FSH secretion through negative feedback.
- Testosterone is crucial for male sexual differentiation, secondary sex characteristics, spermatogenesis, and anabolism.
- In target cells, testosterone is converted to dihydrotestosterone, a more potent androgen, by the enzyme 5-α-reductase.
Hyperprolactinaemia
- High plasma prolactin levels can lead to amenorrhea, sexual dysfunction, infertility, and potentially breast cancer.
- High prolactin levels inhibit GnRH release, reducing gonadotropin (LH and FSH) production and inhibiting gonadal hormone synthesis, resulting in infertility.
- Causes can be physiological (e.g., stress, pregnancy), hypothalamic (e.g., damage to pituitary stalk), pituitary tumors (microadenomas, macroadenomas), or drug-induced.
Hirsutism and Virilism
- Increased plasma free androgens or increased tissue sensitivity to androgens can lead to hirsutism (increased hair growth in male pattern) or virilism (masculinization).
- Testosterone is the main androgen.
- Causes of hirsutism include familial, PCOS, adrenal or ovarian tumors, Cushing’s syndrome, and exogenous androgens.
- Virilism features include increased male pattern hair growth, voice deepening, and breast atrophy.
- Common causes of virilism include adrenal or ovarian tumors, Cushing’s syndrome, and exogenous androgens.
Polycystic Ovary Syndrome (PCOS)
- PCOS is characterized by hyperandrogenism, anovulation, and abnormal ovarian morphology.
- It is the most common cause of anovulatory infertility.
- Symptoms include hirsutism, menstrual disturbances, enlarged polycystic ovaries, and infertility.
- Increased plasma testosterone and androstenedione levels are common.
- LH may be elevated, with normal FSH.
- Reduced SHBG levels can lead to increased free testosterone.
- Plasma prolactin levels may also be high.
- Ultrasound reveals multiple small subcapsular ovarian cysts.
- Associated with insulin resistance, obesity, elevated insulin levels, hyperlipidemia, glucose intolerance, and hypertension.
Infertility
- Primary infertility refers to a couple who have never conceived after a year of unprotected intercourse.
- Secondary infertility refers to a couple who have conceived previously but are unable to do so now.
- Even with a regular menstrual cycle, ovulation and luteal development should be evaluated.
Female Infertility Investigations
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Plasma progesterone levels during the luteal phase (day 21) can indicate ovulation.
- Normal levels suggest ovulation.
- Low levels (< 30 nmol/L) suggest ovulatory failure.
- High levels (> 100 nmol/L) suggest pregnancy.
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Plasma FSH, LH, and estrogen levels can help determine the cause of infertility.
- High FSH and LH with low estrogen indicate hypergonadotrophic hypogonadism (ovarian failure).
- Low FSH, LH, and estrogen indicate hypogonadotrophic hypogonadism (pituitary or hypothalamic disease).
- A GnRH test can evaluate pituitary and hypothalamic function.
- Normal response is a doubling of LH and FSH levels after injection.
- Pituitary hypofunction is indicated by a lack of rise in LH and FSH.
- An exaggerated response can indicate hypothalamic disease.
- Plasma prolactin levels should be checked to exclude hyperprolactinemia.
- Thyroid function tests should be conducted to rule out thyroid disease.
- Ovarian ultrasound can monitor follicular development and ovulation and exclude PCOS.
- Anti-Müllerian hormone (AMH) levels can assess ovarian reserve; low levels indicate poor reserve.
Male Infertility Investigations
- Semen analysis evaluates sperm count, motility, and morphology.
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Plasma testosterone, LH, and FSH levels should be measured.
- High FSH and LH with low testosterone indicate hypergonadotrophic hypogonadism (testicular issues, like Leydig cell failure).
- Low FSH, LH, and testosterone indicate hypogonadotrophic hypogonadism (pituitary or hypothalamic disease).
- High FSH compared to LH may indicate seminiferous tubular failure (Sertoli cell failure).
- A GnRH test can evaluate pituitary and hypothalamic function as described above.
- Plasma prolactin levels should be checked to exclude hyperprolactinemia.
- Thyroid function tests should be conducted to rule out thyroid disease.
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A human chorionic gonadotrophin (hCG) stimulation test can assess Leydig cell reserve.
- hCG shares a subunit with LH and stimulates Leydig cells to produce androgens.
- It has a long half-life and can elevate plasma testosterone after 72-120 hours.
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Description
Test your knowledge on the reproductive system, including hormone production and the roles of the hypothalamus and pituitary gland. This quiz covers key concepts such as GnRH, LH, FSH, and prolactin secretion. Challenge yourself with questions about the functions of ovaries and androgens.
