If a patient is on testosterone therapy, what changes can one see in LH and FSH levels?

Appeared in: AIIMS Patna NO - 2020

Explanation

Exogenous testosterone (from therapy) increases blood testosterone levels, triggering a negative feedback loop.
High testosterone directly inhibits the hypothalamus from secreting Gonadotropin-Releasing Hormone (GnRH).
It also directly inhibits the anterior pituitary gland from secreting Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH).
This dual inhibition results in a decrease in the circulating levels of both LH and FSH.

Option A: This option is incorrect. Increased LH would stimulate more testosterone production, but high testosterone levels from therapy actually suppress LH.
Option B: This option is incorrect. While LH would be decreased, FSH would also be decreased due to negative feedback, not increased.
Option C: This option is incorrect. This would indicate a lack of negative feedback. Testosterone therapy enhances negative feedback, suppressing these hormones.

Clinical Relevance

Nursing practice connection: Use the key finding related to Endocrine feedback mechanisms, specifically the Hypothalamic-Pituitary-Gonadal (HPG) axis to guide bedside assessment, documentation, and the next nursing action.
Monitoring LH and FSH is a standard part of managing patients on testosterone replacement therapy (TRT). Suppressed levels confirm the systemic effect of the exogenous hormone.
Understanding this feedback is crucial for diagnosing different types of hypogonadism. High LH/FSH points to a testicular problem (primary), while low/normal LH/FSH with low testosterone points to a pituitary or hypothalamic issue (secondary).
The suppressive effect of exogenous androgens is the basis for their illicit use as male contraceptives and by athletes to manipulate hormone levels, which can lead to infertility and other health issues.

How to Approach the Question

First, identify the key components of the question: exogenous testosterone, LH, and FSH.
Recall the normal hormonal regulation pathway: Hypothalamus (GnRH) -> Pituitary (LH/FSH) -> Testes (Testosterone).
Remember the principle of negative feedback: the final product (testosterone) inhibits the production of the stimulating hormones (GnRH, LH, FSH).
Apply the principle to the scenario: adding external testosterone will significantly increase the blood levels of the final product.
Deduce the outcome: The high testosterone level will strongly inhibit the pituitary gland, causing a reduction in the secretion of both LH and FSH.
Select the option that matches this deduction: Decreased LH and decreased FSH.

Concept Tested & Keywords

Concept Tested: Endocrine feedback mechanisms, specifically the Hypothalamic-Pituitary-Gonadal (HPG) axis.
Stem keywords: testosterone therapy, LH levels, FSH levels
Lead-in keywords: what changes
Negative lead-in flag: false

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E6 Physiology Guyton 4SAE Part 3 p. 27-29

Practise the full AIIMS Patna NO - 2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.