Ovulation modulation

Figure 50-9 The regulatory feedback loop of the hypothalamic-pituitary-gonadal axis. Neural and sensory input from the brain elicits the release of Gn-RH. Gn-RH in turn stimulates the synthesis and release of the gonadotropins FSH and LH, which act on the gonads (ovary and testes) to elicit the ripening and ovulation of the ovary and steroidogenesis (estradiol and progesterone) in the female and spermatogenesis and testosterone production in the male. Inhibin formed by the ovaries and testes along with estradiol and testosterone negatively feeds back to the hypothalamic-pituitary axis to modulate Gn-RH, FSH, and LH release.

Hesla, J.S., Preutthipan, S., Maguire, M.P., Chang, T.S.K., Wallach, E.E., and Dharmarajan, A M. (1997). Nitric oxide modulates human chorionic gonadotropin-induced ovulation in the rabbit. Fertil. Steril. 67 .548-552. 

Tamoxifen Variants The earliest triphenylethylene identified as an ER modulator is clomiphene (Clomid ) and was identified by Merrell in 1958. The compound was intended to be used as a contraceptive, based on its contraceptive activity in rat. However, it behaved exactly the opposite in woman, inducing ovulation and improving subfertility. The compound was therefore marketed as a therapy for infertility. The commercial preparation consists of a mixture of enclomiphene and zuclomi-phene, the latter acting as an agonist. Yet, even 50 years after it discovery, clomiphene... 

Times indicated (in hphCG) are based on ovulation of the oocyte donors approximately 12 hr after hCG administration. Because highest rates of enucleation and fusion occur in recently ovulated oocytes, the times indicated may have to be modulated depending on the time of ovulation after hCG injection. The interval between hCG and ovulation is subject to seasonal variation and breed differences. 

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