During fetal development, testicular descent from the posterior abdominal wall to the scrotum occurs in two phases. Which hormone is primarily responsible for the first (transabdominal) phase of testicular descent?
- A Insulin-like 3 (INSL3) ✓
- B Anti-Mullerian hormone (AMH)
- C Testosterone
- D Human chorionic gonadotropin (hCG)
Correct answer: A. Insulin-like 3 (INSL3)
Explanation
INSL3 from fetal Leydig cells drives the transabdominal phase by causing swelling of the gubernaculum. Testosterone drives the inguinoscrotal (second) phase. INSL3 mutation causes cryptorchidism in animal models. This distinction between the two phases and their hormonal control is a well-established concept in reproductive endocrinology.
Reference: Ganong's Review of Medical Physiology, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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