1. Regulation of menstruel cycle “ovarian function and its endocrin control”
N.Cem FIÇICIOĞLU, M.D., Ph.D.AA.,MBA.
Professor and Director
Department of Gynecology & Obstetrics and IVF Center
Yeditepe University, School of Medicine
İstanbul

2. FEMALE REPRODUCTIVE SYSTEM
 HORMONAL REGULATION OF OOGENSIS AND OVULATION
HYPOTHALAMUS release of GnRF which stimulates release of LH and FSH from the adenohypophysis (ANTERIOR PITUITARY)

4. To understand the menstruel cycle , ıts helpful to divede cycle into 3 phases;
Folliculer phase
Ovulation
Luteal phase

5. Folliculer phase Recruitment
In the human ovary the end result of this folliculer development is usually one surviving matur follicle
This process, which occurs over the space of days

8. Folliculer phase cont..
Features a series of sequential actions of hormones and autocrine / paracrine peptides on the follicle, leading the follicle destined to ovulate through a period of initial growth from a primordial follicle , through the stages of the preantral, antral, and preovulatory follicle

9. FEMALE REPRODUCTIVE SYSTEM
 OVARIAN FOLLICLES
(1) PRIMORDIAL FOLLICLES
(2) GROWING FOLLICLES
(a) early primary follicle
- follicular cells still unilaminar but now are cuboidal in appearance
- oocyte begins to enlarge
(b) late primary follicle
- multilaminar follicular layer; cells now termed granulosa cells
- zona pellucida appears; gel-like substance rich in GAGs
- surrounding stromal cells differentiate into theca interna and theca externa
(b) secondary (antral) follicle
- cavities appear between granulosa cells forming an antrum
- follicle continues to grow
- formation of cumulus oophorus and corona radiata
(3) MATURE (GRAAFIAN) FOLLICLES

10. Primordial follicle
Primordial germ cells orginate in the endoderm of the yolk sac,allantois and hindgut of embryo and 5-6 weeks of gestation have migrated to genital ridge.
Rapid mitotic multiplication of germ cells… gestation weeks ..the maximal number of ooctes reached. 6-7 million in both ovaries. ( 2 million at birth and at puberty).
The primordial follicles consist of an oocyte, arrested in the diploten stage of meiotic prophase

11. Primordial follicle, cont.
The visible signs of recruitment or when the oocytes increases in size, in response to FSH, small gap junctions develop between the granulosa cells and the oocyte. The initiation of follicule growth is independent of gonadotropin stimulation.

12. Preantral follicle
Fsh stimulation propels follicles to the preantral stage
Fsh-induced aromatization of androgen in the granulosa results in the production of estrogen
Together, FSH and estrogen increase the FSH receptor content of the follicle
The success of a follicle depends upon its ability to convert an androgen micrenvironment to an estrogens micrenvironment

13. Antral follicle
Follicular phase estrogen production is explainedby the two cell, two gonadotropin mechanism
Selection of dominant follicle is established during days 5-7and consequently estradiol begin to rise significantly by day 7
Estradiol negative feed backs effects and supressive influence on FSH release

15. Antral follicle cont..
While directing a decline in FSH levels the mid folliculler rise in estradiol exerts a positive feedback influence on LH secretions ( 200 pg/ml, 50 hours )
LH levels rise steadily during the late luteal phase stimulating androgen production in the theca
Follicular response to gonadotropin is modulated by a variety of growth factors and autocrin and paracrine peptides

16. Preovulatory follicle
Acting through its receptor LH initates luteinization and progesteron production in the granuloza layer
The preovulatory rise in progesterone facilitiesthe positive feedback action of estrogen and may be required to induce the midcycle FSH peak
A midcycle increase in local and peripheral androgens occurs , derived from the thecal tissue of lesser, unsuccesful folicles

17. Ovulation
A threshold of LH concentration must be maintained for hours in order for full maturation of oocyte to occur
LH surge stimulate resumption of reduction division in the oocyte, luteinization of granuloza cells and synthesis of progesterone and prostaglandin within follicle
Progesterone enhances activity of proteolytic enzymes responsible for digestion and rupture of follicular wall

18. more than 200 pg /ml > 50 hours
Positive feed back of E2
more than 200 pg /ml
> 50 hours

19. 14-27hours for full maturation of the oocyte to occur
A threshold of LH
14-27hours
for full maturation of the oocyte to occur

20. Ovulation cont..
The progesterone – influenced midcycle rise in FSH serves to free the oocyte from follicler attachment, to convert plasminogento to the proteolytic enzyme plasmine, and to ensure that the sufficient LH receptor are present to allow an adequate normal luteal phase

21. Luteal phase
Normal luteal function requires optimal preovulataory follicle develepment
In early pregnancy HCG maintains luteal function until plasental steroidogenesis is well established. “9-10 gestation weeks”

22. Thank you,

24. Antral follicle cont.. İnhibin supress FSH secretion
Activin augments FSH secretion
IGF- I ; DNA synthesis, sterediogenesis, aromatase activity, LH receptor synthesis, inhibine secretion