Follicular growth

FSH Pituitary Stimulates follicular growth (female) Enhanced spermatogenesis (male)... 

Typically, 400 follicles will mature and fully ovulate during an average woman s reproductive lifetime. The remaining 99.98 per cent of her follicles begin to develop, but regress due to inadequate FSH stimulation. The molecular detail of how FSH (and FH) promotes follicular growth is described in the main body of the text. 

Gonadotrophins are also used in assisted reproduction procedures. Here the aim is to administer therapeutic doses of FSH that exceed individual follicular FSH threshold requirements, thus stimulating multiple follicular growth. This, in turn, facilitates harvest of multiple eggs, which are then available for in vitro fertilization. This technique is often employed when a woman has a blocked fallopian tube or some other impediment to normal fertilization of the egg by a sperm cell. After treatment, the resultant eggs are collected, incubated in vitro with her partner s sperm, incubated in culture media until the embryonic blastocyst is formed, and then implanted into the mother s uterus. 

Follicular Growth and Ovulation, Estrogen and Progestin Production... 

Menotrophin Urine of post-menopausal women Contains FSH with some LH activity. Used to induce human follicular growth... 

Ovarian follicular growth and maturation will occur during hMG or FSH treatment of gonadotropin-deficient women. Ovulation requires administration of chorionic gonadotropin when adequate follicular maturation has occurred. 

Hirshfield AN (1994) Relationship between the supply of primordial follicles and the onset of follicular growth in rats. Biol Reprod, 50 421-428. 

Ultrasound examination Follicular growth, ovarian cysts... 

Measuring serum FSH on cycle day 3 is probably the most widely used invasive test to measure ovarian reserve (S8, T4). When natural cycles are monitored, follicular growth rate is slower in young women with high FSH levels compared to controls with normal FSH levels (Al). In natural IVF cycles, raised FSH is associated with an increase in cancellation rates for poor follicular development, although... 

In adult women, a tightly coordinated feedback system exists between the hypothalamus, anterior pituitary, and ovaries to orchestrate menstruation. FSH serves to stimulate follicular growth and LH stimulates ovulation and progesterone secretion from the developing corpus luteum (see Figure 53-8). These actions are discussed in greater depth later in this chapter. 

The laboratory plays an important role in the process of ovulation induction. The principle involves administration of gonadotropins to stimulate follicular growth followed by hCG to stimulate ovulation. Clinical, laboratory, and ultrasound monitoring of the treatment cycle is necessary to (1) determine the dose and length of therapy,... 

For example, the induction of metabolizing enzymes by a chemical can greatly modify its PK and that of other substances, which is the subject of metabolic interactions [59], Intestinal barrier alterations due to intestinal toxicity can also affect PK [3]. Toxicity-induced retro-action mechanisms can also increase volumes of distribution The interaction of a chemical with aromatase can lead to a decrease in estradiol production and hence a decrease in FSH secretion, followed by a decrease in follicular growth and a reduction of the ovary volume [56], This should have implications for the design of in vitro assay systems. Integrated systems, such as those coupling metabolism and effect observations in human on chip micro-devices [5], offer a way to model experimentally the PK/PD continuum. 

The menstrual cycle consists of the follicular phase and the luteal phase, each lasting about 2 weeks. The follicular phase is a period of ovarian follicular growth (follicu-logenesis) that results in ovulation (release of secondary oocyte). This phase is dominated by estrogen produced by the growing follicle itself. During the follicular phase, the... 

Leinweber B, Colli C, Chott A, et al. Differential diagnosis of cutaneous infiltrates of B lymphocytes with follicular growth pattern. Am J Dermatopathol. 2004 26 4-13. 

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