KEY POINTS

Development of the Reproductive System

1, Organization of the gonads is under genetic control.

2. Sexual organization of the genitalia and brain depends on the presence or absence of testosterone.

Hypothalamopituitary Control of Reproduction

1. The hypothalamus and anterior pituitary (adenohypophysis) secrete protein and peptide hormones, which control gonadal activity.

2. The adenohypophysis (pars distalis) produces follicle-stimulating hormone, luteinizing hormone, and prolactin, all of which control reproductive processes.

Modification of Gonadotropin Release

Ovarian Follicle Development

1. Gamete development occurs initially without gonadotropin support and subsequently with pulsatile gonadotropin secretion.

2. In the preantral follicle, gonadotropin receptors for luteinizing hormone develop on the theca, which results in androgen synthesis; follicle-stimulating hormone directs the granulosa to transform the androgens to estrogens.

3. Late in the ovarian follicular phase, luteinizing hormone receptors develop on the granulosa, which permits the preovulatory surge of luteinizing hormone to cause ovulation.