21. Although similar in some ways to mixed gonadal dysgenesis, the conditions can be distinguished histologically. 22. They also regulate many hormones including pituitary, gonadal and hypothalamic hormones as well as insulin. 23. About the seventh week the distinction of sex in the gonadal ridge begins to be perceptible. 24. On the right, the gonadal veins and suprarenal veins drain into the inferior vena cava directly. 25. FSH is subject to oestrogen feed-back from the gonads via the hypothalamic pituitary gonadal axis. 26. Once gametogonia enter the gonadal ridge, however, they attempt to associate with these somatic cells. 27. The sex ratios are female biased because xenoestrogens interrupt gonadal configuration causing complete or partial sex reversal. 28. In contrast to FSH, LH has little role in male fertility outside of inducing gonadal testosterone production. 29. At this point it is usually possible for a physician to make a diagnosis of XX gonadal dysgenesis. 30. Inhibin has been shown to regulate gonadal stromal cell proliferation negatively and to have tumor-suppressor activity.
