Hypothalamic-Pituitary-Ovarian Axis — MCQs
Progesterone production in the ovary is primarily by:
The best drug to lower prolactin levels in a female with infertility is:
On which day LH & FSH should be measured?
Positive feedback action of estrogen for inducing luteinizing hormone surge is associated with which of the following steroid hormone ratios in peripheral circulation?
In the transition from a Graafian follicle to a functional corpus luteum, which of the following cellular events occurs?
By which mechanism do LH and FSH primarily return to baseline levels after ovulation?
Hypothalamus increases release of all hormones from the pituitary except ?
The menstrual cycle can be best assessed by:
A woman with two children presents with galactorrhea and amenorrhea for one year. The most probable diagnosis is:
A 35-year-old woman presents with 4 months of amenorrhea, increased FSH, LH, and decreased estrogen. What is the most likely diagnosis?
Hypothalamic-Pituitary-Ovarian Axis Indian Medical PG Practice Questions and MCQs
Question 1: Progesterone production in the ovary is primarily by:
- A. Corpora albicans
- B. Corpora lutea (Correct Answer)
- C. Stroma
- D. Mature follicles
Explanation: ***Corpora lutea*** - The **corpus luteum** forms after ovulation from the remnants of the ovarian follicle and is the primary source of **progesterone** during the luteal phase of the menstrual cycle and early pregnancy. - Its main function is to prepare the **endometrium** for implantation and maintain pregnancy. *Corpora albicans* - This is the **scar tissue** left after the degeneration of the **corpus luteum** when pregnancy does not occur. - It is **inactive hormonally** and does not produce significant amounts of progesterone. *Stroma* - The **stroma** is the connective tissue framework of the ovary that supports the follicles. - While it contains cells that can produce some **androgens**, it is not the primary site of **progesterone** production. *Mature follicles* - **Mature follicles** (Graafian follicles) primarily produce **estrogen** in preparation for ovulation. - Although they produce some progesterone just before ovulation, the **corpus luteum** is the main producer after ovulation.
Question 2: The best drug to lower prolactin levels in a female with infertility is:
- A. Bromocriptine (Correct Answer)
- B. GnRH
- C. Testosterone
- D. Corticosteroids
Explanation: ***Bromocriptine*** - **Bromocriptine** is a **dopamine agonist** that directly inhibits prolactin secretion from the pituitary gland [1]. - It is highly effective in lowering prolactin levels and restoring ovulatory function, making it the preferred treatment for **hyperprolactinemia-induced infertility** [1], [2]. *GnRH* - **Gonadotropin-releasing hormone (GnRH)** stimulates the release of LH and FSH, but it does not directly lower prolactin levels. - In cases of hyperprolactinemia, high prolactin can actually inhibit GnRH pulse frequency, so administering GnRH without addressing prolactin would be ineffective or counterproductive. *Testosterone* - **Testosterone** is a male androgen and has no direct role in lowering prolactin levels in women. - Administering testosterone to a female would likely cause virilizing effects and would not address the underlying cause of infertility. *Corticosteroids* - **Corticosteroids** are used to reduce inflammation and suppress the immune system, but they do not have a direct mechanism to lower prolactin levels. - While stress (which corticosteroids can sometimes help manage) can influence prolactin, corticosteroids are not a primary treatment for hyperprolactinemia.
Question 3: On which day LH & FSH should be measured?
- A. 1-3rd day (Correct Answer)
- B. 7th day
- C. 14th day
- D. 10th day
Explanation: ***1-3rd day*** - Measuring **LH** (Luteinizing Hormone) and **FSH** (Follicle-Stimulating Hormone) on cycle days 1-3 provides a baseline assessment of **ovarian reserve** and pituitary function. - At this early follicular phase, hormone levels are relatively stable and reflect the intrinsic **gonadal feedback** mechanisms before significant follicular development begins. *7th day* - By day 7, **follicular development** is usually well underway, and FSH levels might be decreasing as a dominant follicle is selected. - Measuring hormones on this day would not provide an accurate baseline assessment, as the levels are already influenced by **follicular growth**. *14th day* - Day 14 is often associated with the **LH surge** that triggers ovulation, making it unsuitable for a baseline assessment of ovarian reserve. - FSH levels would also be significantly different from the early follicular phase due to the ongoing **ovarian cycle events**. *10th day* - On day 10, **estrogen levels** are typically rising, which would already be providing negative feedback to the pituitary, affecting FSH and LH levels. - This timing would not be ideal for assessing baseline hormone levels for **fertility evaluations**.
Question 4: Positive feedback action of estrogen for inducing luteinizing hormone surge is associated with which of the following steroid hormone ratios in peripheral circulation?
- A. High estrogen : high progesterone
- B. High estrogen : low progesterone (Correct Answer)
- C. Low estrogen : high progesterone
- D. Low estrogen : low progesterone
Explanation: ***High estrogen : low progesterone*** - A sustained period of **high estrogen** levels, produced by the developing follicle, is crucial for triggering the **LH surge** through positive feedback. - At this pre-ovulatory stage, **progesterone levels remain relatively low**, as significant progesterone production only begins after ovulation from the corpus luteum. *High estrogen : high progesterone* - While high estrogen is required for the LH surge, **high progesterone levels** would typically occur *after* ovulation, suppressing LH rather than inducing its surge. - High progesterone usually exerts negative feedback on the hypothalamus and pituitary, preventing an LH surge. *Low estrogen : high progesterone* - **Low estrogen** levels are insufficient to exert the positive feedback necessary for an LH surge. - **High progesterone** during this phase would also inhibit GnRH and LH secretion. *Low estrogen : low progesterone* - Neither low estrogen nor low progesterone levels are conducive to the LH surge; this combination often characterizes the **early follicular phase** or the **late luteal phase/menstruation**, where ovarian activity is minimal. - The LH surge requires a specific hormonal milieu involving elevated estrogen.
Question 5: In the transition from a Graafian follicle to a functional corpus luteum, which of the following cellular events occurs?
- A. Granulosa cells begin to express estrogen receptors
- B. Granulosa cells begin to express LH receptors (Correct Answer)
- C. Theca cells begin to express androgen receptors
- D. Granulosa cells begin to express progesterone receptors
Explanation: ***Granulosa cells begin to express LH receptors*** - During the late follicular phase, under **FSH** stimulation, **granulosa cells** in the developing Graafian follicle acquire **LH receptors**. - This acquisition of LH receptors is essential for the transition to a corpus luteum, as it enables the **LH surge** to trigger ovulation and subsequently stimulate **luteinization** and **progesterone production** by the corpus luteum. - While the initial expression occurs before ovulation, the functional significance becomes apparent during the transformation to the corpus luteum, making this the most critical receptor-related event in this transition among the given options. *Granulosa cells begin to express estrogen receptors* - Granulosa cells already express **estrogen receptors** in early follicular stages, which are essential for their proliferation and **aromatase synthesis**. - Estrogen receptor expression is characteristic of developing follicles throughout folliculogenesis, not specifically associated with corpus luteum formation. *Theca cells begin to express androgen receptors* - **Theca cells** produce **androgen precursors** (androstenedione, testosterone) under LH stimulation during the follicular phase, which granulosa cells convert to estrogen. - While theca cells contribute to the corpus luteum (theca-lutein cells), androgen receptor expression is not the primary defining cellular event of this transition. *Granulosa cells begin to express progesterone receptors* - The corpus luteum is the major source of **progesterone** in the luteal phase, but granulosa cells do not significantly upregulate progesterone receptors as part of their luteinization. - The key functional change is the cells' ability to *produce* large amounts of progesterone in response to LH, not increased progesterone receptor expression.
Question 6: By which mechanism do LH and FSH primarily return to baseline levels after ovulation?
- A. Negative feedback on GnRH from testosterone
- B. LH surge
- C. Negative feedback on GnRH by estradiol
- D. Negative feedback on gonadotropin-releasing hormone (GnRH) by progesterone (Correct Answer)
Explanation: ***Negative feedback on GnRH by progesterone*** - After ovulation, the **corpus luteum** secretes **progesterone** (and estradiol), which exerts powerful **negative feedback** on the hypothalamus and pituitary - **Progesterone** is the **dominant hormone** in the **luteal phase** that suppresses **GnRH** pulsatility, leading to decreased secretion of both **LH** and **FSH** to baseline levels - This negative feedback maintains low gonadotropin levels throughout the luteal phase until corpus luteum regression *Negative feedback on GnRH by estradiol* - **Estradiol** does provide negative feedback, particularly in the **early-mid follicular phase**, where it primarily suppresses **FSH** secretion - In the luteal phase, estradiol works **synergistically with progesterone**, but **progesterone is the dominant feedback signal** for returning both LH and FSH to baseline after ovulation - Estradiol alone (without progesterone) triggers the **LH surge** via positive feedback at high concentrations *Negative feedback on GnRH from testosterone* - This mechanism is specific to **males**, where **testosterone** from Leydig cells provides negative feedback to regulate **GnRH**, **LH**, and **FSH** secretion - In females, testosterone plays only a minor role in feedback regulation of the hypothalamic-pituitary-gonadal axis *LH surge* - The **LH surge** is a **positive feedback** phenomenon triggered by high **estradiol** levels in the late follicular phase - This represents the **peak** of LH secretion that triggers ovulation, not a mechanism for returning LH and FSH to **baseline** levels - After the surge, LH falls due to negative feedback from progesterone and estradiol during the luteal phase
Question 7: Hypothalamus increases release of all hormones from the pituitary except ?
- A. ACTH
- B. TSH
- C. FSH
- D. Prolactin (Correct Answer)
Explanation: ***Prolactin*** - The hypothalamus primarily **inhibits prolactin release** from the anterior pituitary via **dopamine** (prolactin-inhibiting hormone). - All other hormones listed (ACTH, TSH, FSH/LH, GH) are stimulated by their respective hypothalamic releasing hormones. *ACTH* - The hypothalamus **increases ACTH release** by secreting **corticotropin-releasing hormone (CRH)**, which acts on the anterior pituitary. - CRH stimulates corticotrophs to synthesize and release ACTH, which then acts on the adrenal glands. *TSH* - The hypothalamus **increases TSH release** by secreting **thyrotropin-releasing hormone (TRH)**, which stimulates thyrotrophs in the anterior pituitary. - TRH also has a minor stimulatory effect on prolactin release, but its primary role is TSH stimulation. *FSH* - The hypothalamus **increases FSH release** (along with LH) by secreting **gonadotropin-releasing hormone (GnRH)** in a pulsatile manner. - GnRH stimulates gonadotrophs in the anterior pituitary to produce and secrete both FSH and LH.
Question 8: The menstrual cycle can be best assessed by:
- A. Fern test
- B. Spinnbarkeit phenomenon
- C. Sex steroid profile (Correct Answer)
- D. Cytology of endometrium
Explanation: ***Sex steroid profile*** - A **sex steroid profile** directly measures the levels of key hormones like **estrogen** and **progesterone** throughout the cycle, providing the most comprehensive and accurate assessment of ovarian function and phases [2]. - Changes in these hormones dictate the events of the menstrual cycle, including ovulation and endometrial preparation [2]. *Fern test* - The **fern test** assesses cervical mucus crystallization patterns, primarily indicating high estrogen levels, but it doesn't give a full picture of the entire cycle or progesterone influence [1]. - It's mainly used to confirm **rupture of membranes** in pregnancy or indicate the ovulatory phase [1]. *Spinnbarkeit phenomenon* - **Spinnbarkeit phenomenon** refers to the stretchiness of cervical mucus, which primarily indicates high estrogen levels around ovulation [1]. - While useful for ovulation detection, it does not provide a comprehensive assessment of the entire female sexual cycle or hormonal fluctuations [2]. *Cytology of endometrium* - **Endometrial cytology** involves examining cells from the uterine lining, which can show the effects of hormonal exposure but doesn't directly measure hormone levels or provide a dynamic assessment of the entire cycle [3]. - It is more commonly used to detect **abnormal cellular changes**, such as hyperplasia or malignancy.
Question 9: A woman with two children presents with galactorrhea and amenorrhea for one year. The most probable diagnosis is:
- A. Ectopic pregnancy
- B. Prolactinoma (Correct Answer)
- C. Pituitary apoplexy
- D. Hypothalamic dysfunction
Explanation: ***Prolactinoma*** - The classic presentation of **galactorrhea** (milk production unrelated to pregnancy or breastfeeding) and **amenorrhea** (absence of menstruation) in a non-pregnant woman strongly suggests hyperprolactinemia, most commonly due to a **prolactin-secreting pituitary adenoma** (prolactinoma). - High prolactin levels can inhibit GnRH pulsatility from the hypothalamus, leading to decreased LH and FSH secretion, which in turn causes **anovulation** and thus amenorrhea. *Ectopic pregnancy* - This condition presents with symptoms like **abdominal pain**, vaginal bleeding, and a **positive pregnancy test**, which are not mentioned here. - While an ectopic pregnancy is a cause of amenorrhea, it does not typically cause galactorrhea. *Pituitary apoplexy* - This is an acute, life-threatening condition caused by hemorrhage or infarction of the pituitary gland, presenting with **sudden severe headache**, visual disturbances, and altered mental status. - While it can affect pituitary function, its acute onset and severe symptoms are inconsistent with the one-year history of galactorrhea and amenorrhea. *Hypothalamic dysfunction* - Although hypothalamic dysfunction can cause amenorrhea due to impaired GnRH release, it typically presents with **low or normal prolactin levels**, not elevated prolactin causing galactorrhea. - Conditions like **functional hypothalamic amenorrhea** (due to stress, excessive exercise, or low body weight) would involve a different hormonal profile.
Question 10: A 35-year-old woman presents with 4 months of amenorrhea, increased FSH, LH, and decreased estrogen. What is the most likely diagnosis?
- A. Premature ovarian insufficiency (Correct Answer)
- B. Menopause
- C. Late menopause
- D. Perimenopause
Explanation: ***Premature ovarian insufficiency (POI)*** - The patient's age (35 years) combined with 4 months of **amenorrhea**, increased **FSH** and **LH**, and decreased **estrogen** is characteristic of premature ovarian insufficiency (also called premature ovarian failure). - The hormonal profile (**hypergonadotropic hypogonadism**) indicates ovarian failure occurring before the age of **40 years**, which defines POI. - POI affects approximately **1% of women under 40** and can present with amenorrhea, infertility, and symptoms of estrogen deficiency. *Menopause* - Menopause is diagnosed after **12 consecutive months of amenorrhea** in a woman, typically occurring around age **51 years** (natural menopause). - While the hormonal profile of elevated FSH/LH and low estrogen is consistent with menopause, the patient's **age of 35 years** and **only 4 months of amenorrhea** do not meet the criteria for natural menopause. *Late menopause* - Late menopause refers to menopause occurring at a later age than average, typically after age **55 years**. - This diagnosis is completely inconsistent with the patient's age of 35 years. *Perimenopause* - Perimenopause is the transitional phase leading up to menopause, characterized by **irregular menstrual cycles** and **fluctuating hormone levels**. - While FSH levels may be elevated at times, perimenopause typically shows **variable hormone levels** rather than the sustained pattern of high FSH/LH with low estrogen seen in this case. - The **sustained amenorrhea** and pronounced hormonal shifts indicate ovarian failure (POI) rather than perimenopausal transition.
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