Follicular maturation

In females, menotrophins and hCG are used for the treatment of anovulatory infertility. This condition is due to insufficient endogenous gonadotrophin production. Menotrophin is administered to stimulate follicular maturation, with subsequent administration of hCG to promote ovulation and corpus luteum formation. Mating at this point should lead to fertilization. 

Most superovulatory regimes utilizing p-FSH entail its administration to the recipient animal twice daily for 4-5 days. Regular injections are required due to the relatively short half-life of FSH in serum s.c. administration helps prolong the duration of effectiveness of each injection. The 4 or 5 days of treatment with FSH is followed by a single dose of LH, promoting final follicular maturation and ovulation. 

The pituitary releases a mid-cycle LH surge that stimulates the final stages of follicular maturation and ovulation. Ovulation occurs 24 to 36 hours after the estradiol peak and 10 to 16 hours after the LH peak. 

Pharmacology Medroxyprogesterone, when administered IM at the recommended dose to women every 3 months, inhibits the secretion of gonadotropins which, in turn, prevents follicular maturation and ovulation and results in endometrial thinning. These actions produce its contraceptive effect. 

During the follicular phase of the menstrual cycle, one or more follicles are prepared for ovulation. FSH and estrogens are the most important hormones for this developmental process. Complete follicular maturation cannot occur in the absence of LH. Rupture of a mature follicle follows the midcycle peak of LH and FSH by about 24 hours. In humans, usually one mature ovum is released per cycle. During the luteal phase of the menstrual cycle and under the influence of LH, the ovarian granulosa cells of the corpus luteum become vacuolated and accumulate a yellow pigment called lutein. 

Mechanism of Action A hormone that influences proliferative endometrium and transforms into secretory endometrium. Secretion of pituitary gonadotropins is inhibited which prevents follicular maturation and ovulation, TircrapeuticEffect Facilitates ureteral dilatation associated with hydronephrosis of pregnancy. 

Chang P, Kenley S, Burns T, Denton G, Currie K, DeVane G, O Dea L. Recombinant human chorionic gonadotropin (rhCG) in assisted reproductive technology results of a clinical trial comparing two doses of rhCG (Ovidrel) to urinary hCG (Profasi) for induction of final follicular maturation in in vitro fertilization-embryo transfer. Fertil Steril 2001 76(l) 67-74. 

Loumaye EEuropean Recombinant LH Study Group. Human recombinant luteinizing hormone is as effective as, but safer than, urinary human chorionic gonadotropin in inducing final follicular maturation and ovulation in in vitro fertilization procedures results of a multicenter double-blind study. J Clin Endocrinol Metab 2001 86(6) 2607-18. 

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. 

In hypothalamic hypogonadism and for in vitro fertilization, one or two ampules are administered daily for 5-12 days until evidence of adequate follicular maturation is present. Serum estradiol levels should be measured and a cervical examination performed every 1 or 2 days. When appropriate follicular maturation has occurred, hMG or FSH is discontinued the following day, hCG (5000-10,000 IU) is administered intramuscularly to induce ovulation. 

Ovidrel Choriogonadotropin alfa Serono 10/2003 Induction of final follicular maturation and early luteinization CHO... 

B7. Ben Rafael, Z., Kopf, G. S., Blasco, L., Flickinger, G. L., Tureck, R. W. et al., Follicular maturation parameters associated with the failure of oocyte retrieval, fertilization, and cleavage in vitro. Fertil. Steril. 45, 51-57 (1986). 

As reviewed before," differences in results obtained in IVEP systems are caused by various factors such as time taken to transport ovaries to lab after collection, temperature changes during ovary collection and transport to the laboratory, cow breed, oocyte quality and follicular, maturation, fertilization and embryo culture environments. In particular, cattle breed has been shown to influence developmental competence of oocytes and blastocyst rates. The effect of breed on oocyte quality is amplified by environmental conditions. For example, although Holstein cows Bos taurus) have bigger ovaries, they produce oocytes of lower quality compared to Brahman cows Bos indicus) However, for both cases, the in-vitro-fertilized embryos at the 4- and 8-celI stage when subjected to heat stress results in decreased blastocyst rate but the effect is more severe in Holstein embryos compared to zebu embyros. ... 

Megestrol acetate is a progestin that inhibits secretion of pituitary gonadotropins, thereby preventing follicular maturation and ovulation (contraceptive effect) inhibits spontaneous uterine contraction and transforms proliferative endometrium into secretory endometrium. It is indicated as a palliative treatment of advanced inoperable, recurrent, or metastatic carcinoma of breast or endometrium. 

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