Mullerian inhibiting substance is produced by?

NHM UP Staff Nurse - 2016

Applied Physiology

Easy

Appeared in: NHM UP Staff Nurse - 2016

Explanation

Mullerian Inhibiting Substance (MIS), also known as Anti-Müllerian Hormone (AMH), is produced by the Sertoli cells within the fetal testes.
This hormone is essential for normal male development.
Its primary function is to cause the regression (involution) of the Müllerian (paramesonephric) ducts, which are the precursors to female internal reproductive organs like the uterus and fallopian tubes.
This process of Müllerian duct regression is typically completed by 10 weeks of gestation.

Option A: Stroma is the supportive connective tissue of an organ. It does not have a primary role in producing Mullerian Inhibiting Substance.
Option C: Leydig cells are responsible for producing testosterone, not MIS. Testosterone is vital for the development of the male internal duct system (Wolffian ducts) and external genitalia.
Option D: This option is incorrect because only Sertoli cells produce MIS. Leydig cells and stroma have different functions.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal control of fetal sexual differentiation as background academic context rather than a clinical decision trigger.
A deficiency in MIS production or a defect in its receptor in a 46,XY male fetus results in Persistent Müllerian Duct Syndrome (PMDS). Individuals with PMDS have normal male external genitalia but also possess a uterus and fallopian tubes.
Measuring serum AMH levels is a valuable diagnostic tool. In pediatrics, it helps confirm the presence of functional testicular tissue in infants with ambiguous genitalia or undescended testes. In gynecology, it is used to assess ovarian reserve in women.
What if? If a male fetus has a defect in the AMH receptor, MIS will be produced but cannot act on the target tissues. The clinical outcome would be the same as an MIS deficiency: Persistent Müllerian Duct Syndrome (PMDS), with the presence of a uterus and fallopian tubes in a genotypic male.

How to Approach the Question

First, identify the key term in the question: 'Mullerian inhibiting substance' (MIS). Recognize this is a specific hormone involved in development.
Recall the basic embryology of the reproductive system. Remember that early embryos are bipotential, possessing both Müllerian (female precursor) and Wolffian (male precursor) ducts.
Associate the key hormones with their specific cell types and functions in male differentiation.
Link MIS (also called AMH) to the Sertoli cells and its function: to inhibit the Müllerian ducts.
Link testosterone to the Leydig cells and its function: to promote the Wolffian ducts.
Evaluate the options based on this knowledge. Sertoli cells are the direct source of MIS. Leydig cells and stroma have different roles. Therefore, 'Sertoli cells' is the only correct choice.

Concept Tested & Keywords

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E6 Gynecology Williams p. 434-436

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1292-1294