This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Physiology & Histology, Subject name: Gynaecology & Obstetrics
[{'content': 'Function of inhibin: \nSelect and explain. \nA. Inhibin A/B is useful tumor marker for Sertoli-Leydig tumors., B. Inhibin-B Produces positive feedback for FSH, C. Inhibin-A decreases in trisomy 21 (Down syndrome), D. Inhibin-A decreases in trisomy 18 (Edwards syndrome)', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. d. Inhibin-A decreases in trisomy 18 (Edwards syndrome)Inhibin A/B is useful tumor marker for Granulosa cell tumors.FSH binds to Sertoli cells and activates a Gs --cAMPpathway. Sertoli cellsRelease inhibin B, which has negative feedback on FSH secretion.Trisomy 21 with down syndrome, levels for MS-AFP and estriol are decreased, but hCG and inhibin-A are, increased. Perform an amniocentesis for karyotype.Trisomy 18 With Edward syndrome, levels for all 4 markers (MS-AFP, estriol, inhibin-A, and hCG) are decreased. Perform an amniocentesis for karyotype.', 'role': 'assistant'}]