Diabetes Mellitus USMLE Step 1 Practice Question
A 33-year-old man with poorly controlled type 2 diabetes presents with decreased libido and infertility. He has used metoclopramide chronically for severe gastroparesis. Vital signs are normal (BP 128/82, HR 72, RR 16, Temp 98.6°F). Laboratory studies show prolactin 85 ng/mL (normal <20), testosterone 180 ng/dL (normal 300-1000), and LH 2.1 mIU/mL (normal 1.7-8.6). HbA1c is 9.2%. Erectile dysfunction testing is normal. Which mechanism best explains his hypogonadism?
Answer choices
- AInhibition of hypothalamic GnRH releaseCorrect answer
- BOverproduction of adrenal androgens
- CDirect destruction of Leydig cells by prolactin
- DUpregulation of Sertoli cell inhibin B
- ESuppression of TSH receptor signaling
- FCompetitive antagonism of androgen receptors in the testes
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