Ovary follicle maturation

Like urofollitropin, it is marketed for enhancing the development of multiple follicles that can then be induced to ovulate, via hCG administration, so that the oocytes can be collected for IVF. It also is used in treating women who wish to become pregnant and are anovulatory because of polycystic ovary syndrome, in whom it can enhance follicle maturation before hCG administration for final ovulation. All commercial products can be administered by SC injection. The RFF notation signifies Revised Formulation Female, and the RFF Pen notation indicates a prefilled, ready-to-use device designed to make self administration easier. 

The sex steroid hormones are produced by the mature cells of the gonad. Estrogens are produced mainly by the ovary during maturation of the follicles and by the placenta. Progesterone is secreted during the elaboration of the corpus luteum and by the placenta. The interstitial cell of the testicle is the main source of testosterone. 

Ovulation Periodic ripening and rupture of a mature follicle and the discharge of an ovum from the cortex of the ovary. 

LH secretion which induces rupture of the follicle and release of the mature egg into the fallopian tube. In the ovary a corpus luteum forms, which secretes progesterone (maximal at about day 21) to prepare the endometrium for implantation of an early embryo. If pregnancy does not occur, the corpus luteum involutes, progesterone levels fall, and the thickened endometrium is shed giving rise to menstrual bleeding, which is defined as starting on day 1 of the next cycle. 

Contraceptive. An agent that diminishes the likelihood of or prevents conception. Corpus luteum. A yellow glandular mass in the ovary formed by an ovarian follicle that has matured and discharged its ovum. If the ovum has been impregnated, the corpus lu teum increases in size and persist for several months. 

In females, the target organs are the ovaries where it increases the number and size (maturation, development and ripening) of Graafian follicles and prepare them for ovulation. During its development, the ovarian follicles secrete its own hormone estrogen. In males, it stimulates spermatogenesis. Under the influence of this hormone, seminiferous tubules produce spermatozoa. 

Receptor sites for angiotensin II, the main active peptide of the renin-angiotensin system, have been found in the ovaries (Lightman et al., 1989). Ovarian renin-angiotensin may also have an autocrine role in angiogenesis, steroidogenesis and oocyte maturation. Inhibin is produced by the ovarian follicle and corpus luteum (Tsonis et al.,... 

The LH surge is the primary impetus for ovulation. During ovulation, the mature follicle ruptures, releasing the ovum from the ovary. At this point, the ovum should begin to travel toward the uterus via the fallopian tubes. The ruptured follicle remains in the ovary and continues to play a vital role in the reproductive cycle. After releasing the ovum, the follicle becomes infiltrated with lipids and is referred to as the corpus luteum (yellow body). The role of the corpus luteum is described next. 

Ovarian follicles, the basic unit of the ovary, consist of an outer layer of theca interna cells which encircle inner layers of granulosa cells. Granulosa cells, in turn, surround the innermost oocyte-cumulus complex. This complex array of cell layers is essential for the maturation and ovulation of the ovum. Significantly, the granulosa cell, by virtue of its close interaction with the outer theca and inner oocyte-cumulus compartment, serves to integrate information necessary for the achievement of successful follicular development. 

The ovaries perform two major functions (i) the storage, maturation, and expulsion of healthy haploid germ cells (i.e., oocytes) for fertilization, and (ii) the synthesis and secretion of hormones to prepare the reproductive tissues for the establishment and maintenance of pregnancy, to properly regulate gonadotropin secretion from the hypothalamic-pituitary axis, to induce appropriate sexual behaviors, and to provide lactation. The two primary functional units in the ovaries are the maturing follicles and the corpora lutea. 

Q1 The primordial follicles in which ova develop, form in the embryo and the maximal number 1-2 million, is present at birth. Follicles are located in the cortex of the ovary and each contains a primary oocyte. Following sexual maturation at puberty about 200 000 follicles remain, some of these will develop into primary follicles. During reproductive life a number of the primary follicles develop further, leading to ovulation, the remainder decline (a process known as atresia). 

The number of ovarian follicles capable of maturation is fixed at birth. They are depleted by age, and in older women approaching the menopause few follicles remain. At around the time of the menopause (perimenopause) oestrogen levels fall and the ovaries also gradually lose their responsiveness to FSH and LH so that the process of ovulation and fertility is impaired. 

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