WBR0336

Author	[[PageAuthor::Rim Halaby, M.D. [1] (Reviewed by Alison Leibowitz)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Physiology
Sub Category	SubCategory::Genitourinary
Prompt	[[Prompt::The image below illustrates the normal development of male genitalia, initiated following the expression of testis-determining factor by the SRY gene on the Y chromosome. In human males, there is a clear relationship between levels of testosterone and Mullerian inhibitory factor (MIF) or anti-Mullerian hormone (AMH). Which of the following statements best describes the relationship between testosterone and AMH? ]]
Answer A	AnswerA::Only serum testosterone inhibits anti-Mullerian hormone in the puberty period but not in the neonatal period.
Answer A Explanation	AnswerAExp::Serum testosterone does not have a major role in the inhibition of anti-Mullerian hormone.
Answer B	AnswerB::Only Serum testosterone inhibits anti-Mullerian hormone in the puberty period and in the neonatal period.
Answer B Explanation	AnswerBExp::Serum testosterone does not have a major role in the inhibition of anti-Mullerian hormone.
Answer C	AnswerC::Only intratesticular testosterone inhibits anti-Mullerian hormone in the puberty period but not in the neonatal period.
Answer C Explanation	AnswerCExp::In the neonatal period, Sertoli cells lack any androgen receptors. Thus, AMH is not inhibited by testosterone in the neonatal period. However, intratesticular testosterone inhibits AMH in the pubertal period.
Answer D	AnswerD::Only intratesticular testosterone inhibits anti-Mullerian hormone in the puberty period and in the neonatal period.
Answer D Explanation	AnswerDExp::Intratesticular testosterone does not inhibit AMH in the neonatal period.
Answer E	AnswerE::Both serum and intratesticular testosterone inhibit anti-Mullerian hormone in the puberty period and in the neonatal period.
Answer E Explanation	AnswerEExp::Serum testosterone does not have a major role in the inhibition of anti-Mullerian hormone. AMH is not inhibited by testosterone in the neonatal period.
Right Answer	RightAnswer::C
Explanation	[[Explanation::Anti-mullerian hormoner (AMH) or mullerian inhibitory factor (MIF) is secreted by the immature Sertoli cells. In the neonatal period, AMH levels are elevated and are not inhibited by the action of testosterone because Sertoli cells in the neonatal period lack any receptors for androgens. In converse, when males reach puberty, AMH levels are significantly decreased, suggesting pubertal development of the Sertoli cells. Remarkably, the decrease in AMH levels are seen before the rise of serum testosterone levels is seen in male subjects at puberty. This observation led to the discovery that intratesticular testosterone is the real inhibitor of AMH at puberty. This physiological process is absent in patients with androgen-insensitivity, whereby AMH levels remain elevated by the function of FSH without any inhibitory effects of androgens. Educational Objective: Intratesticular testosterone inhibits AMH (or MIF) in the pubertal period, but not in the neonatal period. Treatment with FSH increases AMH, whereas treatment with exogenous testosterone decreases AMH due to the inhibition of endogenous intratesticular testosterone. References: Al-Attar L, Noel K, Dutertre M, et al. Hormonal and cellular regulation of Sertoli cell anti-Mullerian hormone production in the postnatal mouse. J Clin Invest. 1997; 100(6):1335-1343.]]
Approved	Approved::Yes
Keyword	WBRKeyword::testosterone, WBRKeyword::intratesticular, WBRKeyword::neonatal, WBRKeyword::puberty, WBRKeyword::anti-Mullerian, WBRKeyword::hormone, WBRKeyword::hormones, WBRKeyword::inhibitory, WBRKeyword::Sertoli, WBRKeyword::cells, WBRKeyword::androgen, WBRKeyword::androgens, WBRKeyword::receptors, WBRKeyword::SRY, WBRKeyword::genes, WBRKeyword::testes
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