Sexual differentiation in humans development can only occur when the fetal testis secretes key hormones at a critical period in early gestation. The testes begin to secrete three hormones that influence the male internal and external genitalia: they secrete anti-müllerian hormone (AMH), testosterone, and dihydrotestosterone (DHT). Anti-müllerian hormone causes the paramesonephric ducts to regress. Testosterone converts the mesonephric ducts into male accessory structures, including the epididymis, vas deferens, and seminal vesicle. Testosterone will also control the descending of the testes from the abdomen into the scrotum. Many other genes found on other autosomes, including"WT-1", "SOX9", "SF-1" also play a role in gonadal development. Females:
Trophic hormone causes hyperplasia of enterochromaffin cells which may transform into carcinoid tumors. Trophic hormone Trophic hormone is a hormone that has a growth effect, hyperplasia or hypertrophy, on the tissue it is stimulating. The term "trophic" is from Ancient Greek τροφικός ("trophikós") meaning "pertaining to food or nourishment", here used to mean "growth"; this is the same origin as "atrophy." This should not be confused with "tropic," as in the similar-sounding tropic hormone – the words and concepts are both unrelated. A key example of this is thyroid-stimulating hormone stimulating the thyroid; excess thyroid-stimulating hormone can create a goitre. Trophic hormones