Practice question

Leydig cells originate from mesenchymal progenitors in interstitial compartment under Desert hedgehog signaling from Sertoli cells and transcription factor Sf1. They express steroidogenic acute regulatory protein and enzymes Cyp11a1, Hsd3b1, Cyp17a1 converting cholesterol to testosterone. Their principal product testosterone secreted in fetal life stabilizes Wolffian ducts differentiating into seminal vesicles, epididymis and vas deferens, supports masculinization of brain and later promotes spermatogenesis. Testosterone also serves as precursor for dihydrotestosterone in external genitalia and estradiol in brain. Insufficient function causes female phenotype.