Endocrine System MCAT Practice Question
A clinical trial evaluates a novel GnRH antagonist administered to treat prostate cancer in men. GnRH antagonists rapidly block GnRH receptors on gonadotroph cells. Patients receive the antagonist continuously for 12 weeks. Which of the following correctly describes the expected hormonal changes resulting from sustained GnRH antagonism?
Answer choices
- AIncreased FSH and LH, followed by decreased testosterone due to loss of Leydig cell stimulation
- BImmediate and sustained suppression of FSH and LH, leading to decreased testosterone productionCorrect answer
- CIncreased GnRH production by the hypothalamus due to loss of negative feedback from gonadotropins
- DSustained elevation of testosterone as Leydig cells become supersensitive to residual LH
- EDecreased LH but increased FSH due to selective antagonism of FSH receptors on Sertoli cells
- FInitial suppression of FSH and LH followed by rebound elevation due to upregulation of GnRH receptors on gonadotroph cells
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