Ovarian endocrine function is devolved to the follicle cells surrounding the oocyte during its development and from which will form the corpus luteum.
As the gamete formation, the endocrine function of the ovary is cyclical secretion of ovarian hormones occurs at a pace that is superimposed on the reproductive cycle.
Ovarian castration has different effects depending on the age at which it is used:

  • before puberty, it causes the persistence of infant genital tract, absence of puberty, obesity;
  • After puberty, it causes regression of the genital tract, mitigation of secondary sexual characteristics, the suppression of reproductive function cycle arrest genital obesity.
  • The administration of ovarian hormones corrects the effects of castration. At excessive doses, they cause the child early development of the genital tract and its annexes.

The ovary secretes four groups of hormones estrogen, progesterone, a small amount of androgens and the group of inhibin and cybernines. Unlike other hormones, inhibin and cybernines are not steroid.

Estrogens.
They are three in number, produced by cells of the theca interna; estradiol, the most active, estrone and estriol
Their physiological actions are as follows;

  • actions on the reproductive tract and sexual characteristics;
    • they lead hypercontractility horns;
    • at the uterine body, they promote the development of uterine muscle and endometrium;
    • in the vagina, they cause the appearance on the smear of surface cells;
    • in the breast they cause hypertrophy of the mammary gland;
  • metabolic actions, estrogen promotes the calcium binding protein on the frame of bone and lean early growth plates. They also promote fluid retention (hence problems with osteoporosis at menopause);
  • other actions in women, estrogen facilitates the development of fibroids and cancers of the breast in humans, they cause atrophy of sex organs (penis, epididymis, seminal vesicles), a decrease of spermatogenesis and production testosterone.



Estrogens, partly destroyed by the liver, are mainly excreted through urine as estriol.

Progesterone.
It is developed outside of pregnancy by the granulosa cells (yellow body), and during pregnancy by the placenta.
The physiological role of progesterone focuses on the preparation and maintenance of pregnancy and the destruction of the corpus luteum in early pregnancy leads to stop it.
It exerts its action;

  • genital tract;
    • level of the uterus, it softens the muscle where it inhibits uterine contractions, and it complements the action of estrogens on the mucosa.
    • in the vagina, it changes the appearance of smears (the appearance of cells Plicata);
    • in the breast, she enlarged mammary glands;
  • during pregnancy, it inhibits the contractility of the uterus and prevents the expulsion of the ovum.
  • Other activities: it facilitates the metabolism of estrogen and has an elevation of temperature.

Progesterone is excreted in urine as pregnanediol.
It now manufactures synthetic progestins, which, by blocking ovulation, are used for contraceptive purposes.

Androgens.
The ovary secretes a small amount of androgen secreted primarily by the ovarian stroma.
They act primarily on the pubic and axillary hair.

Inhibin and cybernines
The ovarian inhibin has similar actions at the pituitary and hypothalamus that testicular inhibin. In the ovary, inhibin is involved in follicular maturation.
Cybernines modulate the actions of FSH and LH in the follicle. Several cybernines are currently known:.
The study of ovarian hormones showed some secretory specialization of the different constituents of ovarian parenchyma since:

  • the theca cells secrete estrogen;
  • the granulosa cells secrete progesterone, inhibin and cybernines;
  • Finally, the stromal cells develop ovarian androgens.

The ovarian hormone cycle.
From the first to fourteenth day cycle: follicular maturation occurs under the influence of FSH secreted by the pituitary gland. The secretion of pituitary FSH is itself triggered by a hypothalamic control center that develops a hormone called LHRH. which stimulates the pituitary secretion. The hypothalamic control center has a cyclical activity and its secretion is dependent on circulating estrogen levels and the secretion of inhibin and cybernines.
As and when the maturation of the follicle, its cells secrete estrogen which increases the rate throughout this period. Estrogens cause changes in uterine and vaginal mucous membranes studied in the previous chapter. They also act on LHRH secretion which in turn causes the secretion of pituitary LH;
In the fourteenth day of the cycle, the secretion of pituitary LH peaked determines spawning ovular;
During the second half cycle, the activity of the corpus luteum is controlled by the pituitary gland secretion of F. SH is lower and the LH is dominant, taking under its control hormonal secretion of the corpus luteum. It simultaneously secretes estradiol and progesterone and the association controls the transformation of endometrium (uterine lace) and vagina. The closure of these different hormonal secretions marks the end of the cycle and the onset of the rules. Atrophy of the corpus luteum is under periodic dependence of inhibitor binding LH receptors.
During the second half cycle, there is also a secretion of pituitary prolactin explains congestion premenstrual breast but does not affect the course of the ovarian hormone cycle. In contrast, during pregnancy, prolactin secretion increases dramatically which determines the changes of pregnancy-the mammary gland and, subsequently, postpartum lactogenesis.
The onset of ovarian activity occurs at puberty in hypothalamic-pituitary control, and that the emergence of endocrine secretions of the ovary is responsible for changes in the reproductive tract and the appearance of characters secondary sex.
The cessation of ovarian endocrine activity takes place about fifty years it is menopause.

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  2. The Pituitary
  3. The Hypothalamus
  4. The Adrenal
  5. Thyroid